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ABSTRACTS
1. A n unexpected associatwi~of factors b d o n g h g to t h r e e lziilage groups &n
Princeton University.
Oenothera and Cts explanation. GEORGEH. SHULL,
I n a family of Oenothera which was segregating for the three pairs of factors,
rubricalyx vs. green hypanthia, long styles vs. brevistylis, and yellow vs. old-g01d
flowers, representing, respectively, the first, second, and third linkage groups,
thrre was found a deficiency in the rnbriotllyx groups, dur apparently to the
linkage of the rubricalyx factor with a factor for somichloralbinism, together
with the retarding effect on development, of the factor for old-gold flower color
and short styles. There was, notwithstanding this partial elimination, a marked
excess of the class showing the association of the three dominnnt traits, rubricalyx
Buds, long styles, and yellow ff owers, representing a combination of three factors
which had been associated in the maternal grandmother. This unexpected and
striking excess of the traits of one grandmother seemed to imply the linkage
of factors belonging to three different linkage groups-a condition which ought
t o be expected if the linkages in Oenothera are due to the end-to-end cohesion of
non-homologous chromosomes. When preparing t o test this suggrsted linkage,
it was found that fifteen of the twenty-nine rubricalyx long-styled yellows were
triploids produced by 14-chromosome eggs, which had failed to go through the
reduction division, fertilized by 7-chromosome sperms. Omitting these triploids,
the ratio of different phenotypes in the family no longer suggests a linkage
between factors previously found t o be independent.
2. A c m e of douhling of chromosom~sin the genus Nicotinna. W. R. SINGLETQN,
Bussey Institution, Harvard University, and Connecticut Agricultural Experiment Station. (Iatroduced by E. M. East.)
A cross was mado between h’icotinna rustica liumilis Sclirnnk and K. paiiiculata
The seeds from this cross germinate
nearly 100 per cent, wheretis the seeds from the reciproeal hybrid all fail to
gormina te.
The F, hybrid is intermediate, resembling more closely the rustiea parent,.
It is only a fraction of a per cent fertile. Only a few of the flowers produce
any sccds, and these never more than ten seeds per capsule.
About 200 P, plants were grown and examined f o r fertility and chromosome
number. They ranged in fertility from 0 t o 100 per cent. The chromosome
numbers also proved interesting. K. paniculata has 1 2 (haploid), N. rustica
hag 24, and the F, has 12 pairs a n d 15 univ:ilentq, a total of 36 chromosomes.
Several of the F2plants were apparently regular in both first and second reduction
twice the number
divisions and h a d 36 pairs, a total of 72 chromosomes-.just
in the Fl plants.
These plants were in the most cases nearIy completely fertile when selfed, or
crossed by the rustica parent, but were completely sterile with the other parent,
N. paniculata.
93
Id., using the former as the female parent.
94
AMER.ICAK SOCIETP OF ZOOLOGISTS
:?. Xfw miderrcc beuriit,,q upole t h e j ~ r o b l e no~f the c*ytologic.al basis for (rr.netic’n1
i?j, the oeriotkrms. RALPHE. (;LELAND A N D FR.OEHIXERS,(;onelicr
College.
The authors hsve midc u study of the cytology and breeding 1)ehnvior of :I.
large number of F, hybrids betwccn several species of 0enot.hera. They find
tlt:.it hybrids possessing e.i.rcles composed of twelve or fourteen cliroi
true in pr:ict,ic:illy evcrg particular, vdiereas those with smaller
nomlier of piired ehroniosomes show ;L ccrt.ain amount of splitting. 1.t is thus
shown t h a t t h e chronioso~nesof a singlc circle constitute the basis f o r a singlt.
linkage group. It is further demonstrated that genes governing visible c.haract.ers
:ire scattered throughout t.hc various chromosomes and :irc not confined f o r t.he
most p a r t to a single chromosome, :is postulated by Shull.
.#. I.rLherit n ~ i c e of sentis t e r
i,n rrtuisc. R. A. BRINKA N D C. K. HURNIIAII,
University of Wisconsin.
Semisterile maize pla.nts appear identical with their normal sibs except t.h:it
they produce 50 per cent abort.ed pollen grains and ovules. Tlie niatings normal
2 x semisterile $, semisBerile 0 x nornial$, a.ud semisterile sclfed give equal numlisrs of normal :ind semisterile offspring. It was suggested tlritt in semisterile
plxnts :i section of one nicmber of :t cliromosonic! p i r is removcd from its normil
position and nffixed to a non-homologous chromosome. The modificd eliromosomes
apparont,ly assort at random i n meiosis, resulting i n 25 pcr cent of the sporcs
lacking the detached section and 25 per c.ent receiving it in dup1ieat:e. Tliese
c.lasses abort. I n one-half of the functional spores the section responsible f o r
the at.ypira.1 behavior of t.he stock is a.ttached to a non-homologous cliromosome.
Tlicst! sporcs transmit semisterility. According to hypothesis, the normal individuals in a givcii progeny from a normal x semisterile combinntion slioulil g i w
only normal offspring when crossed among themselves. Twenty-four such rnatings
have given only normal offspring, with o m exception probably duc t o contarnination. The normal offspring from a selfed semisterile plant. should comprise t.wo
c.lassrs of individuals in equal numbers, standard normals and x-normals. Crossrli
wi.thin cncli of these g r o u p slioiild give only normal offspring like the parents ;
intergroup comliina tions Should produce all semisterile plants. Of ninet,y-one
mztings hetween norma.1 sibs from selfed semisterile plants, forty-nine gure
all normals and forty-t.wo ga.ve all semisterilcs. The x-norma.1 r.ln.ss is iissumed
to be ‘1iomox.vgous ’ for t.he t.ranslocation. Semisterility is of particular interest
:is one of the mec.liaiiisms bp whivh interspccific st.erility may arise.
5. A Auploitl mu%on.li,~.t h tomato.
~
JC. W. LINDSTROM,
Iowa, St,at.e College.
I n an F, gcneration of 337 plants there occurred a singlc sterile tomato plant
with an unusuiil morphological appenra.nce. An exuminat,ion of the pollen inotlier
cclls proved that only bwelve univalent r.hromosomes were present,, which w~is
later verified by observations of somatic tissue of root tips. The genotype and
phenotype of this exrcpti.ona1 plant showed it t o be the result of the p:irt.henogenetic derelopmcnt of XI, siiigle, crossover gamct,e (factors in first chromosome).
T h u s f a r the haploid h a s proved eompletelp sterilc on the stamiiiate side, b u t
shows 1 to 3 per cent fert.ility when uscd a.s u female parent.. The progeny from
such crosses a r e diploid in nature, with one exception, a n d indicat.e that the
funetional meg:ispores :ire 1:irgely those cont:iining the full quota of twelve
(’11 romosomes.
95
ABSTRACTS
6. The r6le of inhibiting factors in shape inh&tance of squash fruits.
EDMUND
W. SINNOTI-,
Ba.rnard College, Columbia Universit.y.
Evidence is preseiited that in five lines of Cucurbita pepo, in which there is
present. one of t.he two major factors operating to flatten the shape of the fruit,
there also occurs a dominant factor which hihibits tlie operation of either of the
flatteners. This inhibitor is itself without direct effect upon shape and is not
to be confused with fact.ors which produce elongation directly.
7. A lethal factor in Crepis effective ondy
it&
mi. interspccific hybrirl.
LILLIAK
IIOLLIXGSHEAD,
University of California.
Interspccific hybrids of Crepis ciipillaria and Crepis toctorurn reported by
Bahcock and Collins ( ’20) developed only t.o t.he eot.yledon &age. I n renewed
attempt.s to secure. via.ble hybrids using different strains of t,he parenta.1 species
one hybrid population was obtained, half of which were invia,ble, hut ha.lf
matured normally. 1nvest.igations sliom~ed that t.he tect.orum parent had been
heteroxygous f o r a lethal whic.h hnlted the development, of hybrids into which
it entered at the cotyledon stage. Sclfed progeny of the tectorum plant showed
no signs of the lethal, but on crossing the viirious plimts t o c.apillaris it was
evident Dhat the progeny were segregat.ing for the lethal in a 1:2: 1 ratio.
Plants :homozygous for t.hc lethal (11) ga.ve only inviable hybrids, those heterozygons for it (LI) ga.ve hybrids half viable, half inviable, and those homozygous
for its allelomorph (LL) gave only viable hybrids. Progenies from p1ant.s of
each genotype werc grown and their constitution tested by crossing with wpillaris.
All the progeny of 11 proved t o be 11, giving inviable hybrids only. All the
progeny of LL were LL, giving only viable hybrids. Progeny of L1 segregated
in a 111: 21~1:1 LL ratio giving hybrid populat.ions of three kinds, 1 ) all inviable,
2) half viable, half inviable, 3 ) all via.ble.
The viability of the hybrids was independent of the capillark parent and thore
wa.s no differentia.1 germination with respect t.o the lethal.
There is evidence that the same lethiil is effective in hybrids hot,weon tectorum
and t.wo ot.her species, but hybrids with :I third species are unaffected by it.
8. The orcurreme of chroniosonial variants in Nkotiana alatn. T. H. GOODSPEXD
AND PEISCILLA
AVRBY,University of California.
Chromosome counts of soinc one hundred plants show that iiinc pairs is the
CharacterisBic number in R’icotiana a1at.a. Differences in size, the position of
constrictions, and the oecnrrence of sate.llites provide morphological distinctions
between the nine pairs of somatic c.hromosomes. From a monosomic plant,
obtained through controlled pollination, two populations, totaling seventy-niue
plants, have been grown and examined cptologieally. Of fifty-seven plants from
normal 0 X monosomic 8, only two showed Chromosome numbers ot.her t.han 18,
both plants having 1 9 somatic chromosomes. Of twenty-two p1ant.s from monosomic 9 X normal 6,five showed deviating chromosome numbers: 22, 25, 26, 27, 36.
Of the scven plant8 with supernumerary chromosomes, only two, those with 22
and 25 chromosomes, showed marked distinctions from normal in extern:tl
morphologg. Y.M. C. counts confirmed the chromosome number determined in
root tips. Tctraploidy seen in the root tips of one plant was purely somatic, for
96
AXERIGAN SOCIETY OF
zooLoc,is.rs
9 , , ocrurred a t I-M. I n one 19-chromosome plant, non-conjunction of one or
two pairs of chromosomes frequently oceurrcd, resulting in 11-N counts of
8-11, instead of 9-10.
This suggests that the high percentagr of 8-10 11-31
c+ounts reported in N. :iI:ita mag be due to non-conjunction :is well a s noutlis,julwtion. At 11-M considerable numbers of P. AI. C. coiit:iinetl :t single large
spindle with 19 chroinosornes, and diads constituted 13 per ccut of the P. M. C.
:it the tetrad stage. I t is suggested that non-conjunction, non-disjunction, :rnd
diploid gametes aro responsible for the dcviating cliromosomc~numlicrs found.
Y. The frequency of sonmtic muta.tion in aariegatrd pericurp in (:ros.se.s of cnri.r?-
gated .with colorless
9ti.a.aize.
R. A. EMERSON,
Cornell Universit.p.
1.11F2 of crosses of variqyited with colorless m:lizr, somatic, mutotions frnm
vnricgatcd t.o sclf-colorctd pericarp occur more frequently in the hcterozygous,
'VW,than in the homozygous, VV, ears. Different colorless races show differential
effects on the mutability of t.he variegation gene. Colorless segregates from
lietcrozygous light. variegated plants increase t.lw mutability of the mriegation
gent! in crosses less t.1ian d o the colorless raees t,ested. Reciprocal crosses of
rnriegated wit.h colorless a,nd of dark with light variegated storks are not
significantly different, in mut:ltion rate. In crosses of light wit,li d:l.rk variegated
stwks, F1is interniedint,e in variegation gr:tiic, neit,iier p:went, t,ype being dominant.
These observations :ire interpreted by the assumption of rnodifging genes
linkcd with t.hc variegation gene, which affect the mutnbilit.y of t.he latter.
XI. Linkage between qziuntitatiae and qualitative grnes in maize.
of rows and cob color. X. W. LINDSTICOM,
Iowa, State College.
I. Ximbrr
The entire 1:iek of eight-rowctl varirties of corn with red cnl~sled tllr writer
to test f o r association between row number and cob color. A vcrg large series
of crosses of many varieties shows that, in F, and biw.kcross generations, the
distribution for row number on plants with red cobs is statistically different
from those with white cobs. There is also P significant tendency for the eightrowed segregates to possess white cob color. I n view of other investigations
with a similar situation this is interpreted t o mean that one of the many grnes
vontrolling row number is located on the same chromosome (no. 6) with the
gc1rwr:il coli (and pericarp) gene.
21. Some physicochemicnl aspects of tife, m:ictntion, awl evoktiow. eJmom
.~T.EXANDERAND CALVINE. BRIDGES,
Piew York C'itp and California Institute of
Tcchnologg.
Many of the difficulties confronting those who have attcniptcd t.o understand
t,ho nature of life and 'life processes a r o ~ efrom t h e fact that at,tention it-m not
focused o n sufficiently aimple vital unit,s. Ercn thc smdlrst, ccll or inoiiocc~llular
being is an exceedingly complicated st,ructure. In ardcr t.o form a precise
nieehanieal picture of what oc.c.urs in life, we must dissect. down t.hrough tho
layered struct.urc of its matter until we reach t.he simplest unit that can be
regarded as living. The bchavior of t.he tiny ultinmte vital units map then be
interpreted in term8 of phpsieochwiiical concepts.
ABSTRACTS
97
Starting with man as a unit genera.lly eonceded t o be living, the microscope
penetrates to the eel1 as a vital subunit. Cyt.ology reveals as successively lower
unit.s, t.he nucleus and t.he chromosomes. Genetics demonstrat.es that the chromosomes arc composed of hundreds or thousands of genes and suggests the possibility
that the genes are compounded from gene elements or genels. The genes or
genels are of the order of size and structure of small molecular groups or large
molecales. The visible behavior of chromosomes in reproduction (mitosis), c,oupled
with the genetic evidence, indicates that each gene forms a duplicate of itself next
t.o itself, so t.hat. when the t.wo gene strings split a.part, under normal eonditions
each is an exact counterpart of the other.
The view is taken that genes are specific catalytic particles, which, in addition
to having the power specifically to direct chemical change, have also the power
t o adsorb and fix selectively the subunits from which they arc. synthesized, and
thus reproduce or duplicate themselves. This is accomplished by substantially
the sa.me method as ordinary catalysis, except that the catalyst is also the material
whose formation is catalyzed.
If, prior to the self-duplicat.ion of a gene, the gene itself is modified by some
non-lethal agent (x-rays, chemical substances), the gene or genes thus affeeOcd
may reproduce steadilr in the modifird form, and the cell containing such modified
mut.eria1, as well as the clone or living being (biont) formed from it, will show
c,onsequences following on the change in nature and action of its controlling
catalysts, the genes.
The exist.ence of the so-called filter-passing or ultrafiltrable viruses and of
bacteriophages indicates that there are whole series of subeellular bionts and
points t o the possibility that free-living particles may in some cases be of
molecular rank. The first living thing was probably a molecule of this selfreproducing or autocatalytic type.
12. The rate of i n a w e d mutation in relation t o dornaanay, temperatwe, and
dosage.. L. J. BTADLER, University of Missouri.
About 90 per cent of the recognizable mutations induc.ed bg x-ray treatment
of barley may be detected in the seedling stage. By using these as an index of
mutation frequcnc,y, mutation rates f o r large populations may he determined.
The conelusions here reported are based on mutation rates so determined in
about 20,000 head progenies.
Mutation induced in dormant tissue: Mutation was induced by irradiation of
dormant seed, but the mutation rate was much lower than that following similar
treatment. of germinat.ing seed. Dormant seed are much more tolerant of irradiation than germinating seed, and under high dosage yielded mutations at a rate
fully as high as that from germinating seed a t their limiting dosage.
Mutation was induced i n dormant seed whether or not the seeds were planted
immediately after trea.tment.
R,elation of mutation rate to temperature: No significant difference in rate
of mutat.ion was found in samples treated a t loo, 20", 30", 40", and 5OoC., in
eit.her dormant, seed or germinating seed.
Relat.ion of mutation rate t o dosage: The rate of mutation, both in dormant
seed and germinating seed, varies approximately in direct proportion t o the
intensity of irradiation. The average yield of mutations per Roentgen unit is
about eight times as great in germinating seeds as in dormant seeds.
T H E ANATOXICAL BF.COBI), VOL. 41, NO. 1
98
-4MERTCAN SOCIETY OF ZOOLOGISTS
1.3’. Radium expnri.nienlv with Dat.ura. I . The identification and transm.i,ssion o f
lethals of pollewtcibe growth i n F1’sf i o m radium-treated parents. J. T. BucrrROLZ A N D A. F. HLAICESLEE,
IJniversi.ty of Texas and Department of Genetics,
Carncgie Institution.
Radium-treated plants may carry lethal genes whose elimination takes place
after pollination on t.he stigma or in the style. Many such plants were found
and several selected for detailcd study. An F, arising from treated pollen, normal appearing and having twelve bivalent chromosome pairs, was found t o produce pollen in which more than half of the pollen grains remained ungerminated
o n thc st,igma. Tn sonic of the tests of this pollen a larger proportion of the
pollen germinated, but was associated with a high proportion of burst pollen tubes
in the style. Thus thrre was always an elimination of over half of the pollen.
The F2 progcny from this plant appeared normal. When their pollcn was
txsted, about three-fifths of twenty-eight off spring examined were found t o be
heterozpgous for t.his gene. This is approximately a 1: 1 ratio and represents a
condition inherited through t.he female gametophyte, though eliminated in the
male gametophyte during pollen-t,ube growth, preventing the production of
homoxggotes in the F, generation.
Test.s were made on nearly 200 Flplants from radium-treated parents. Vany
were found t o be heterozggous f o r let,hnl genes affecting pollrn germination or
pollen-tube growth, and a number of other F2progcnies were investigat.cd. Controls: El plants from treated stock which did not givo tests for the presence of
pollen-tube lethal genes gave rise to F, progenies which were likewise free from
lethals. Pollen from unt.reated plants in the field in related strains were found t o
be normal.
14. Radium rxperinients with Datura. 11. Pollen abortion, in F,’s from radiumtrcated parents. J. LINCOLN
CAETLEDGEAND A. F. BLAKESLEE,
Unirersity of
Pittsburgh and Dt~partnicntof Genetics, Carnegie Tnstitution of Washington.
Prom a total of 367 F, offspring from radium-treated daturas, the pollen of
which was rxaniined, two wrrc new rhromosomal types with, respectively, + 5 0
and k 75 per cent aborted pollen grains. Of the remainder which were normal
in appearance, eleven showed .t 50 per cent abortion, one showed & 85 per cent
abortion, three had pollen in which about half of the grains were either distinrtly
smaller siec or aborted, and one had half the grains lighter-colored from lark
of starch. Thus, 4.9 per cent of the F, individuals showed a t least half of the
pollen grains abnormal. 1x1 addition, two plants had f 25 per cent of the pollen
aborted. Three normal-appearing plants with k 50 per cent abnormal grains
and one plant with & 25 per cent abortion were tested by selfing. They all
produced F, progenies which segregatcd for plants with normal and with abnormal
pollen. As controls, 934 normal-appearing plants, the off spring of untreated
parents, were tested. Only two of these showed as much as 2 2 5 per cent
ahorted pollen. Pollen abortion following radium treatment may be due to gcnw
or to chromosomal ahnormalitirs.
99
ABSTRACTS
15. Badium experiwients with Datwra. I I I . Chromosomal abnormalities in Fl’s
f r o m radium-treated parents. A. ’DOBOTHYBEBGNER,
SOPHIA
SATINA,
AND A. F.
BLAKESLEE,
Department of Geneties, Carnegio Institution of Washington.
Following radium treatment by Gager in 1921, nearly 18 per cent chromosomal
mutants including thc compound type Nubbin were identified. I n line lA, 0.47
per cent chromosomal mutants have appeared a.mong over 15,000 individuals.
Of fifty-two offspring grown in 1927 from radium-treated parenbs, two were
new types, distinct morphologically, with deficiencies and other chromosonial
abnormalities. Of the remainder which were normal in appearance, two had
1 0 bivalents plus a single ring of 4 chromosomes (1 X) and (1 m) and one
a ring of 4 (M m) plus a chain of 4 (L M). This is a tot.al of nearly
10 per cent with visible chromosomal abnormalities. I n addition, from 333 similar plant,s in 1988, one out of seven examined had a ring of 6 chromosomes, and
three plants not examined cytologica.lly were morphologically distinct and probably abnormal c.hromosomally. The configurations of 4 attached chromosomes
were identified in the F, in three ca.ses. As controls, twenty-two offspring from
an untreated parent showed only twelve bivalents. The attachment of chromosomes is attributed to induced interchange of parts between non-homologous
chromosomes. Similar attachments have been induc,ed in Fl’s between a standa.rd
line and various races from nature.
+
+
+
+
16. B a d h n experimcntx witti I)utrwa. I J7. Fixible gene imtations in radiumtreated and control material. A. G. AVERYAND A. %.’ RLAKESLEE,Dcpa.rtnicnt
of Genetics, Carnegie Institutsion of Washington.
Two recessive genes (swollen and yollow cotyledons) were obtained out of
eighteen Fl’s tested from a capsule which had been treat.ed with radium emanation by Gager in 1921. One recessive (pale leaves) was obtained out of fifty
F1’s from treatment of pollen or pollen tubes in 192i, making for the two
experiments a total of 4.4 prr cent of Fl plants heteroeygous for new genes.
Two new recessive genes have heen obtained following wounding (adherent and
virescent). Haploid? seems to induec gene mutations, since out of 316 F1’s from
a haploid, 7, or 2.8 per cent, were heterozygous f o r new genes. A s controls, from
568 line-1A plants in F, on later generations from a haploid, only one (0.18
per rent) was found heteroqgous for R new genc. Except for this single pla.nt,
F,’s from. a haploid and tho offspring of treated parcnts, no ncw genes have
been discovered in normal plants in any of our cultures.
WINKLEMAS,
Washington Uni17. Visible mutations from radium rays. ELVEXE
versity. (Int.roduced by Caswell Grave.)
18. An analysis of the effects of the different rajls of radium in, producing lethal
mutations i n Drosopliiln. I?R.ANKBLAIR
HANSON,
Washington ‘University.
ICxposure of fruit flies t.0 radium rays produees bot.11 visible a.nd lethal niutat.ions. Un.der heavy exposure, the lethals are so numerous as t o lend themselves
t o exact quantitative work. A series of 1ea.d screens was interposed between the
radium and flies. The thickest screen was 8 mm. thick and the thickness was
halvcd each time unt.il the thinnest screen was & mm. thick. The percentage of
lethal mutations decreased with increasing t.hicknesses of lead, and the resulting
100
AMERICAW SOCIETY OF ZO~LOGISTS
q u i ~ ewas t h r same as thxt of the absoiptioii power of Iead screens for radium
(Ruthcrford). Radium rays were then passed through the same series of lead
screenq into a n ionization chaniber and electroscope. and the amount of ionization
measured. This is the physicist’s method of measuring the amount of ahwrlition
taking place. The ionization curve and the mutation cur\(> ~ F O to
V bc
~
practl
c*all! identical a t all points, showing t h a t the corrrspondencc brtween the nuiiiber
of mutations and the amount of elt.ctrical energy is very exact.
~ ~ m d < J C ~ l f ~ O Ipro&lrctZ
L . S
b y x ruys tn Ilrosophila. 11. J. MULLEK,
Yui\ eruity of Texas, A N D EDGAK
AL‘J ENHTJRG, Rice Institute.
>:xpeI inients wrre arranged to test the frequency with uhich translocations
1)rtwern non homologous (~liioirrosnmesare produced by x-rays in Drosophila. I t
was found that thev arise with nearly thc frequenr? of detectahle gene mutations.
T h q may involve attac~hmf~irts
between a n y two or more of the C ~ ~ O I I I O S ~ I:I ~ C S
X or Y, and 11, ITI, and I V . Thc differcnt breaks in a given chromosonie may
oecur a t diffcreiit levels, a s gcmetically deterinined.
ological stud? of them
has p r o w d that, as previously suspected, different r
ns of the grnetic ninp
I eprrsent the chromosome to cliff errnt scales, the map regions more crowded with
genc’s reprrsenting relatn rIy greater chromosomc lrngths ; this dors not, howri r ~ ,
affect the mlidity of the Irncar order of the genes. When sniall pieces tire translocntccl, inili\idu:rls inheriting thc loss nithout tlir translocation, or \ ice Trrsa
(thus hating chromatin deficirncv or excess), soinetimes lire, showing vharacter
changes that reflect thc, gmic7 unbalance. Such cases h a w made it possible t o
prn\ c that t h r lcft half of the X-chromosoinc is not sex-determining ; probably,
tlicn, scx diffcrentiation is accomphshetl chiefly hy a single gene locus. Trans
locations (even when genically halancrtl) are commonly accompanied hp lrthal
or dc~leteriousc#haracter changes, likr those of gene inutations, which in:Lke it
difficult t o ohtain them honiozygous. I n one case a curious eversporting effrct,
involving more than on(’ locus, arose in the tianslocated region, coincident all^
with the translocation. ‘rransloc.ations r a n l i e produced with such regularity that
sc\eral useful, prcspecifird translocation stocks, needcd as t o d s in other Dro
sophila work, h;i\ e alrrady been conqtructrd to order.
10. Chrontosotiie
rffects of r-rcr!ln and othrr r ~ r r i ~ o i i n i m t nccgrnf<.
l
ALEYAKDFR
WEIX
of M~nnesota.
Among tlicx inutationx and translocat ions produced h!: x rays a r e sereral of
spccial griic+ic intrrest. One of the translocations inrol\ ep. a t least three chroniosonies-the X and the two large autosonies. Of the mutant genes, one, a secwnd
c~lrroinoxomc~
doniinant, causes a mottling of the eye, due apparently tn mutation
tluiing ilex c ~ l o ~ i n i ( ~ n tTlie
.
ficqut~ncyof the mutation renders possible an anal) s i s
(if how the prwrss i s affectcd I)? gcnrtic influences (including SPX) and IJT
1 arious eu\ ironuirntal agents.
ic
STEIPIT,Gniveisity
e f f c r t s of tiir w t m r q ~ t i e \ 1 1 1 dtffertwl q ? i m i f a t i e ~ .
NABOI:RS,
Kansas S t n t r Agricultural C’ollcge.
‘ 1 . Tlic e o n i p t a f i w
ROBERT
I<.
Goldschmi~lth a s recrntly rrviewcd the studies, mainly hiq own, of t h r rffccts
of t h e \amv gencx in different quantities. A clcar case, not included in Golclschniiilt ’s list, of the effects of single genes, and (louhle quantitirs of theni,
ABSTRACTS
101
respectively, among the color charact.eristics of Apotettix eurycephalus, is illustrated in Kansas Teeh. Bull. 1 7 , colored plate, niatings 447, 455, et al., but
otherwise not adequately elaborated. The factors, Y for a dominant large white
spot on and T for a dominant mahogany red over the pronotum, h a w a linkage
relation of about 7 per cent. Therefore, comparisons among the various comY ..-.
binations of these become c!wy. ..+.-$, a singlc gene of each, shows the
Y
T
white spot of Y plainly modified by the mahoga.ny of T ;
+,
doubling
the gene Y , with single T, exhibits t.he white spot conspicuously, with a mere
tinge of thc mahogany in it.; Y
,: doubling of T mit.h single Y, shows
t.ho white spot greatly obscured by the iliahogany. Many eases of this kind have
been not.ed in the breeding of the grouse locusts.
32. Wing productwa i n aphids as affected b y light und temperature. A. FBANKLIN SUULL,
University of Michigan.
I f wingless females of Macrosiphuni solanifolii are alternated daily between
vr-eak light and darkness, the curve of wing production in their offspring rises
with increase of the duration of light t o o maximum a t about eight hours of light,
falls slightly thence up t o twelve hours of light, drops almost to zero a t fourteen
hours, and remains low for all longer daily periods. I n stronger 1i.glit the curve
is higher for the short periods of light, but is nea.rly identical for t.he longer
pcriods. Alternalion between intense and weak light ca.uses marked wing production onl;y if the weak light is of very low int.ensitp. Single exposures t o light. or
darkness have small a.nd irregular effects; repctit.ion is necessary to obtain the
above results.
Characteristic curves of wing production result from, 1) alternating between
light and darkness in the t,ime ratio of 1 t o 2 ; 2) alt,ernating t,welve hours of
darkness with various periods of light, and, 3 ) alternating six hours of light.
with va.rious pcriods of da.rkness.
Tcmperatures must be not o w r 20°C. f o r at least part of the time t.o obtain
these results. As the tempcrature rises above SO", the effec.t of alterna.ting light
and darlmess rapidly decreases until at. 26°C. no wings are produccd.
The explanation tentatively adopted is that some subst.ance produced in the
light is converted into another substance i n darknws, and that this latt,er substance must be present in a eert.ain amount t.o produce wings. Temperature
modifies some part of the process.
33. Eadium experh.ent8 with Uatu.ra. P . Effect8 of rudiztm on pollen-tu.be growth
rats, cmd the seed oritput fo22o?uiag trcat'tirent. J. T. Bucnrior,~AND A. 3'.
BLAKFXLEE,
Unirersity of Texas and Department of Genetics, Carnegie 1nst.itution.
Pollen from normal Sn plants of Datura stramonium was subjected t o treatment with radium-emanat,ion tubes, using different. dosages, and tested for ratr
of pollen-tube gr0wt.h. There was found to be a decrease in growth rate eonsistcntly proportional to the dosage employed, the highest dosages resulting in a
complete failure in the germination of the, pollen. Data werc oht.ained comparing
the effec.t.5of a similar dosage in millicurie hours given by two tubes, one having
four times the strength of the other,
102
AMERICAN
SOCIETY OF ZOOLOGISTS
Seed capsules rcsulting from pollinations with treated pollen were aborted
without enlargement a t high dosages and werc abortcd in stages after enlargement as the dosage was decreased. When still smaller dosages were employed,
matured seeds were obtained and their number per capsule was increased with
:t decrease of dosage. Marked differences in seed output per capsule were obt:iirwd with dosage steps of 0.16 millicuric hour.
11. SNYDER,
?\Tort,h
24. A recessive factor for pol!/dac.f?lZinlr~in ,man. LAUREKCE
Carolina State College.
Polydaetylism, consisting of an extra fift.h finger on ea.eh hand, was found
among the ncgro populat.ion of Pamlieo County, North Carolina. The three
fmnily histories given includc 1 7 1 individwls, fifty-four of whom show the
polydactylisni. The charar.t.cr appears to be inherited as a recessive. It frequent.ly skips generations. There are found eleven families in which polydact,ylous children occurred where both parents were normal. I n one family, where
both parent.s were polydactylous, all ten children had the c.haracter. The possihilitp of imperfect dominance has been considered but does not seem to apply.
There was no indication of sex linkage. Blood-group determinations were made
on 120 of the individuals. These results were analyzed from the standpoint of
linkage. The gene for polydactylism seems t.o he inherited indcpendcntly of t.he
blood groups.
25. Types of mpemumerary chromosom.es itr maizc.
L. F. RANDOLPH,Cornell
University.
:In maize have bccn found supcrnunierary chromosomes of t,hroc types : A )
I)uplicates of members of the typical set.. B) Chromosomes nf approximat.cly
the same size as the smallest members of the typical set, but differing from
t.hrm in form and behavior. C) Diminutive ehromosomes. Type-A chromosomes
appear i n the progeny of triploids crossed with diploids. Individuals possessing
t.hrm are less vigorous than normal plants. Jn meiosis these chromosomes unite
f r w l y with the typica,l hivalents to form trivalent chromosomes. In root,-tip
c.c.llx thcy are indistinguishable from their homologucs. Type-13 chromosomes
are present i n many commercial varieties and genetical cult.ures and seem not
to affect t.he visible characters of the p1a.nt: individuals with as many as ten
or more of thesc chromosomes are vigorous and fcrtile. Chromosomes of this
typc rarely unitc wit.h the typical bivalrnts, but tend to form bi- and inult~ivalent.
groups among themselves, and their meiotic distribution is extremely irregular.
I n root-tip cells they are club-shaped, t,hicker than the nt.hrr ehroninsomes, and
have a terminal fiber attachment. Tho appearance and bcharior of these chromosomcs indicat,e that they arc homologous. Type-C chromosomes, discovered in
tilack Mexic.an sweet corn, resemble those of t.ype B in having uniformity of size!
no marked effect on the plant, a similar meiotic behavior and manner of inheritance. They arc larger than the sat.ellites present in the typical set. Within the
typical sct aro chroniosomes with subt,crminal fiber at,ta,chment,sa,nd with a long
arm similar in length t o the type-B chromosome, and a short. arm similar to the
t.ype-C chromosome. A separation of the arms of such chromosomes may h a w
produced t.hese two types of supernumerary chromosomes.
103
ABSTRACTS
26. Studirs on pigeon hybrids. I I . The ChTO9nOSOln? conditions (ls an index of
differential mortality of embT,IJOS. L. J. COLE, T. 8. PAINTER,
AND AGNES
ZEIMET, University of Wisconsin and Uniyersity of Texas. (Microscopic
preparations.)
Hybrids were studied for the determination of their sex-chromosome constitution. Careful study of the germinal and somatic tissue of pigeons and doves
(Streptopilia risoria) showed them very similar in thcir chromosome makeup,
each species having among some sixty elements six large chromosomes in the
male and five in the female. No other chromosomes approach these in size.
Males have two pairs of V-shaped chromosomes, one pair being larger than the
other, and one pair of rod-like elements. The sex chromosomes are the larger
of the V-chromosomes. The female has only one of the larger V’s and a pair each
of the smaller V’s and rod-like chromosomes.
Testes of nineteen adult hybrids have been studied. All these have the sexehromosome constitution of males.
Cole’s data show that some 60 per cent of the hybrids die after the first few
days of incubation, such embryos undergoing certain well-marked changes prior
t o death. Out of a total of eleven embryos available and preserved t o date,
three showed characteristic signs of dying. Cytologically, these embryos possess
the sex-chromosome constitution of females, i.e., they have on17 one of the large
V-shaped sex chromosomes. The rest of the embryos are chromosomally males.
These results indicate, first, that the adult hybrids are genetically males and
that none of them are transformed females, as has been claimed in some quarters.
Secondly, that females are produced in the cross, but that they die in early
embryonic stages.
27. Chromosome morphology in nine- and ten-parred species of Nicotiana. PRISCILLA AVERY,LILLIANHOLLINGSHEAD,
AND LILLIAN
J. RAUP, University of
California.
N. alata has 18 somatic chromosomes, distinguished by length, position of
constrictions, and the occurrence of satellites: 2 pairs, long, with median constrictions ; 2 pairs, medium, proximal satellites and subterminal constriction ;
3 pairs, medium, with median or submedian constriction; 1 pair, medium, with
subterminal constriction; 1 pair, shorter, with deep subterminal constriction.
In plants with supernumerary chromosomes (19, 22, 25, 26, 27, 36), it is possible
to recognize some of these chromosomal types duplicated. The somatic chromosomes of N. longiflora total 20 and show a characteristic arrangement at metaphase. Several chromosomes lie i n a horizontal plane, arranged like the spokes
of a wheel, the remaining chromosomes standing on end in the center of the
plate. The chromosomes are rod-shaped, with only slight differences in length.
Two pairs have constrictions forming distal heads. The fiber attachment on
each chromosome appears t o be truly twminal. These morphological distinctions
in the somatic, chromosomes of N. alata and N. longiflora are of interest because
the sterile hybrid between these species forms 9,* 1, a t I-M. N. Langsdorffii has 18 somatic chromosomes, which can be separated into four groups,
as follows: 2 pairs, long, with median constriction; 1 pair, medium, with small
proximal satellite; 1 pair with verF large proximal satellites; 5 pairs showing
slight differences in length. The large satellited chromosomes represent a striking
morphological distinction between the somatic sets of N. alata and N. Langsdorffii. The F, brtween them is fertile and shows 9,, a t I-M.
+
104
AMERICAN SOCIETY OF ZOOLOGISTS
28. Linkage of the characters albinism und shaker in the house wou8e. W I L L I A N
H. GATES, Louisiana State University.
In testing the new eharaeter shaker, reported by Lord and Gates (in press),
f o r its linkage relationship to the other characters of the house mouRr, a pinkeyed, short-eared, normal mouse was crossed with an albino shaker. The F2
generation showed strong linkage with albinism. Out of an F2generation of 254,
where cupcctancy i s 144 colored non-shaker: 48 colored shaker: 48 albino nonshakcr : 16 albino shaker, there were actuall3- obtained 187 colored non-shakers :
3 colored shakers : 10 albino nnn-shakers: 54 albino shakers. The non-cross-over
classes show a n excess of 50 per ccnt and the cross-over elasses a deficiency of
X 6 per cent. Thc diffrrrnccs are 15.3 and 15.9, respectively, times thch probahle
error, and thereforc quite significant.
Ttic wsnlts of tlic back cross of the F, gcneration t o the doublr recessive,
albiuo simker, arc not complete, but up to datc show a linkage nf over 90 per cent.
This linkage relation gives thc R W O I U ~ group of thrcc linked characters rvported in the house mouse. The data, while extremely meager, srem to indicate
that linkage is weaker between pink-eye and shaker than between albinism and
shaker; and, therefore, it is likely that the chromosome map will show albinism
Iring betwccn pink-cyr and shaker.
?9. A coinparison o f the G r c t of ratra c1iroinosoinP.s 091 pollen-twbe growlh from
pollcn of ?mrioiis ( 3 n
1 ) t y p m of Datiirrc stramonium. .T. T. BUCIIIIOLZ
ABU
A. 3’. 13LAI<RSLEE, Gnirersity of Texas and Departmcwt of Genetics, Cariiegie
+
lnsti tut ion.
+
1) types arc known in which, u ) the extra ehromosonieh
A nuniber of (%
ma? be transmitted through the pollen under favorable conditions. These usually
tiax a 1)iniotlal distribution of tlic nornial-appearing pollen tubes in thr style,
anti gcnc.tic twts confirm the intcrprc~tationt i r a t the slowcr-growing group rPprPscnts pollcn tubes with ( n
1) chromosomcs.
I n othrr types, ZI) the pollen tuhcs are represented by t w o groups differing in
appearance, a forward normal-appearing group and a group of abnormal-appcar(1
+
ing t a l m (swollen or ruptured).
pollen.
I n othrr (2n
This eondition is not transmitted through the
+
1) typrs, c ) half or slightly more than half of the pollen fails
t o germinate.
Pollen from Rolled, n ( 3 n 1) primary, gii-es the conditions descrihrd
under h. One of its secondarics, Sugar-loaf, gives four elasses of gametophptes,
thnsc whirh grow narmally, a second normal-appearing, but inore retarded group,
a third group resembling in appearance and position the (12
1) tubes of
Rolled, and a fourth group rcpresentcd by the 16 t o 18 per cent aborted pollen.
The first and second groups are the largest and occur in nearly equal proportions,
whilc the third and fourth groups are smaller.
Polyearpic, thr other secondary of Rolled, may have four groups, but only one
(the first, with n chromosomes) is capable of reaching the ovary. Thc Rolled
group is recognizable by the appearance and position of the a1)normal pnllrn
tuhcs, whilc the pollen grains which might produce Polgearpic remain ungerminated on thr stigma, and the ahortcd pollen constitutes a fourth group.
+
+
ABSTRACTS
$(I.
Hybrid vigor in poultry.
I).
105
C. WARREN,Kansas State Agricultural College.
For a romparison of the vigor of two pure breeds with that of hybrids resulting from their crossing, reciprocal matings were made between the single-comb
White Leghorn and the single-comb Rhode Island Red breeds. Matings were so
arranged that hybrid and pure-bred offspring were produced from the same
females during eac,h of tJhe eight hatches. One hundred ninety-seven pure White
Leghorns, 338 R,hode Island R.eds, 173 hybrids from t.he cross Rhode Island Red
male by White Leghorn female, and 176 from the reaiprocal cmss were produced.
The percent.age of mortality to the age of t1irc:e weeks was 5.6 f o r White
Leghorns, 6.3 for Rhode Isla.nd Reds, and 1.4 for t.hc two reciprocal crosses
combinrd. Hybrid males and fcniales each outgrew thc pure-bred offspring (of
the sa.me sex) from their mot.hcrs. Rliodc Island Reds grcw more rapidly than
White Leghorns, and the cross of Leghorn male by R,hodc Islsnd Red fernale
grctw more, rapidly than its reciprocal. The lattcr fact is of interest, since the
slower-growing hybrids are from the cross in which the maternal parent was
from the slower growing of the two breeds crossed. Tho R,hode Island Red hreed
reaches sexual maturity a.t a much greater age than White Leghorns. Females
from the cross Leghorn ma.le by Rho& Island Red female reached maturity a t an
a.g. slightly grcater than the White Leghorns, while the females of t,he reciprocal
cross were more nearly intermedistc with respect t o age at maturity.
31. Innate limitattons of growth ratr C the R I O Z ~ S P . E. C. MACDOU’ELL,W. 11.
GATES, AND C. G . IVIACI)OKELL, Department of Genetics, Carnegie Institution
of Washington, Cold Spring IIarbor, Long Island, New York, and Louisiana
State University.
The study of innate limitations of growth rnte necessihtrs eliminating the
effects of the secondary variables. To accomplish this, averages are usually
relied upon, and much theorizing on the fundamental chemistry of growth has
been h:~scd on averages of populations. But averages do not balance out the
secondnrv variables, since these are of the nature of limitations and to the
extent that any of these is working the nature of the innate processes is concealed. To remove the influence of these serondary limitations optimum eonditions must be maintaincd.
A s prcriously pointed out, prenatal life providrs the niost accurately controlled
conditions for the study of growth in a mammal, and the growth rurve of the
mouse during this period forms a straight line on lognrithmic paper when age
is counted from the appearance of the anlage of thc embryo. After birth, by
increasing the amount of mothers ’ milk available and maintaining favorable
conditions, we have been able to reduce the effect of the secondary limitations
to such an extent that, for fourteen days after birth, curves for individual mice
have been obtained that are nearly mathematically smooth, and rise t o 15 grams,
as against 4.5 to 7 grams in published data. These curves approach a straight
line on logarithmic papcr when age is counted from the anlage of the embryo.
After fourteen days, a sudden break accompanied by a widr scatter among individuals indicates a change in the conditions of life. This is intimately associated
with the first eating of solid food.
106
AMERICAN SOCIETY OF ZO~LOGISTS
,38. Heredit!{ of nziriiuturc ( b o d y ) , an 2 - m y mnlutatwn i n Habmbracon.
WBITING, University of Pittsburgh.
P. W.
Daughter of x-rayed male by untreated female gave rise to two mutations,
short (wings) and miniature (body). Miniature is recessive and semilethal :
females are sterile. Ahout half of miniature males expected from hetcroxygous
mothers fail to mature, but of these about 1 7 per cent develop into naked
pupae, which can be classified with respect to eye color. Miniature shows linkage
with orange (eye), giving nhont 10 per cent crossovers, as shown by maturr
n o r r d , mature miniature, or pupac. There is some evidence that miniature is
hecoming more viable. Heredity of short is under investigation.
33. In.legum.en.ta.1grafting of the Leghorn. fowl.
A . W.
K.OZELX.4,
Univrrsitg
of Pittsburgh.
Secondary sexual structures from day-old chicks were t,ransplanted onto various
1;iart.s of hoily of same individiml and of other individuals under t h e e days of
:tge. Aut.oplastic feather tissues differentiated normally on any part of 1)ody.
Comb appeared to grow best in situ, but was usually somewhat smaller on ot,lier
parts of body. While normal symmetry was maintained in most ca.ses, shape of
some of the graft.ed combs mried from irregular mass t o a roset.te. No innorvation ha.s taken placo in grafted portions. Normal diff erent.iation of autoplastic female spur took place only 011 scaly tissue of shank, rema.ining part.ially
or wholly juvenile on other parts of body. I n mdo, characteristic development
of spur took place on any part of body, wit.h one exception occurring among
twenty-three grafts, where spur remained juvenile. Contra.ry to general belief,
ovary appeared t.0 have no inhihit.ing effoct upon development of male spur. Of
t,hirteen homoioplastic grafts with female as recipient, seven spurs from male
donors differentiated into characteristic male spurs, while thosc from femalo
hehaved like autoplastic spurs. This would seem to indicate that there is genetic
tliffcronw between spurs of two sexes. Work is now in progress t,o :iscwt,ain
infl nonce of sex hormones upon various secondary sexusl characters.
34. A third linkage group i n the killijisk, Plntylpoecilus.
'MYRON GORDON, Cornell Universit~y.
ALLENC. FRASER
AND
Previous reports have recorded a sex-linked group containing tliree fact.ors:
Sp, for b1ac.k sp0t.s all over the body, It for red body color, and N, for the nigra
pattern, a band of black (Bcllamy, '22 and '28; Gordon, ' 2 7 ) . Tlic latt,er had
also reported upon a.n autosomal factor St,, for stippling, an olive gray coloration.
Since 1925, st.udies have been ma.de on four other fsetors for certain melanic
patterns occurring on the caudal peduncle of the fish: T, for t.win-spot, Tb, for
t.win-blotch, 0, for one-spot, and C, for crescent.
By a series of direct. and reciproc.a.1c.rosses and many h:i.ck-crosses, the faet.ors,
T, Tb, 0, and C indicate n o linkage to St for stippling and are not sex-linked.
Thc?y show in some cases definite linkage with one anotlier.
Twin-spot by one-spot yields TtOo (or three spots). TtOo back-crosscd t,o
recessive (ttoo) gave 126 twin-spot.5, 109 one-spots, and a single moss-over TtOo.
The lntter is being tested further.
Evidence, a1t:hough incomplet.e, indicstes that C (crescent,) a.nd Tb (twinlilotch) Iwlong to the same group as t.win-spot and onc-spot.
ABSTRACTS
107
55. A survey of flower colors in the garden balsam ant1 of the geries affecting
them. DONALDW. DAVIS AND LUCYANN TAYLOR,College of William and
Mary.
Flower colors in the garden balsam occur in two series. Of the non-cream
series our homozygous strains include the following colors associated with wholly
green stems: white, nearly white (very slightly tinged with pink), nearly white
with pink spur, pale pink with white spur, pink with pale spur (two types), pink
with deep pink or purplish spur (two types), lavcnder (two types); and, associated with more or less pigmented stems, the following types: pink of various
grades with deep colored spur (two types), scarlet (two types), purple, red,
czoppery red. In the cream series our homozygous stocks include pure cream,
pale cream pink with cream spur, and cream lavender-all associated with green
stems; and cream pink with deep spur (thrce types) associated with colored
stems.
Sixteen crosses have been made involving ten of these twenty-five color types.
Except in a fcw c:tses, these have been cayried through the second, third, 0 1
fourth gencration. Among thc progeny of the crosses and from other sources
eleven additional distinguishable color types are described.
White is a simple dominant to cream. Each of the other non-cream types,
except the scarlets, red, and coppery red, has a recognizable corresponding cream
type which differs from it by the snnie factor as differentiates whitc from cream.
Scarlet is produced by a combination of the factors present in certain palespurred pinks with factors found in certain deep-spurred pinks. Purple results
from a combination of factors found in lavender with those of certain decp
spurred pinks. Red is due t o a combination of certain factors found in scarlet
and purple. Details of crosses and their progeny give indications as to specific
factors and their rchtions.
36. A new t y p e of congemitd hypodactylism of t h e front limbs occurring in
the mkternth t o nineteenth generations of the descendants of x-rayed mice.
HALSEY
J. BAOQ,
Cornell University Mcdical College and Memorial Hospital.
Four thousand three hundred sixteen animals were carefully examined for
foot abnormalities before a sixteenth-generation individual was found with two
digits of a front limb completely missing. In the next three generations (1279
additional mice examined) 37 individuals showed this general type of defect :
males, 1 7 ; females, 20. There were 2 1 feet with one and 19 with two digits
missing, respectively. The anatomical location was as follows: right front limb,
30 instances; left front limb, 4 instances, and three animals with both front
limbs hypodactyl, respectively. Blindness was associated with this defect in
31 animals. Twenty-nine feet, excluding those that were hypodactyl, showed
either clubbing or syndactglism. The solitary kidney condition was present in
T animals and in 3 both kidneys were missing a t birth. An examination of the
breeding records shows that this type of hypodactylism new t o the strain has
arisen apparently in the grandchildren of two fourteenth-generation mice. These
grandparents each had a clubbed foot, respectively, and the strain had been
especially selected for this type of abnormality through the preceding six
generations. It is possible that this is a distinct structural abnormality which
arose possibly as a result of a new genetic recombination. The inheritance of
this defect is being tested.
ioa
37. On
AMERICAN SOCIETY O F ZO6LOGISTS
thP
to siw
several generations of daughters from repeated matings of daughters
H. D. GOODALE,Mount Hope f i r m , Williamstown, hIass:tchusetts.
Tlie daughters of three White Leghorn m:iles have been mated back to their
sire, and the new generation of daughters in turn again mated to their sire.
In out’ init:Lncc this 11:~s been repeiited four times, the last generation of tlnuglrters
tlieoretically averaging thirty-one thirty-seconds of the genes of their sire. Data
relating to the body weight, fertility, nnd egg production of these daughters
~
will I Jpresented.
58. Livi,ng mice a.ml museum .vpecim.mns showing morpkologi.ca1 ab.nomnalities o f
the vi,r.cerck, eye.?, nnd limbs. HALSEY5. BAGG,Cornell TTniversity Medical
College :inti Memorial Hospital.
C.‘h:irts arc shown i.llustrating the inheritance a.nd association of the above
clc*fwts, together with the results of :I, statist.ica.l staciy of :L relativc frequency
in :tnatomica.l location, obtained from the esaminnt.ion of 5636 c1esceildant.s of
s-r:iyed mice. t.hrough nineteen generatioils.
of g m c s and .sex fa.c!tors in intergeneri,c liillifislb hgbritls.
PRASER
ASD MYRONGOBDON, Cornell Unirersity.
J!?. Itlrir.ti.tg
ALLEN C‘.
Kosswig ( ’28) states that in crosses of Xiphophorus helleri and Platgpoecilus
mwulatus t.he scx-linked factms Sp, spot.s, and N, nigra, follow eloso1)- the
nomial hereditarl: 1)cliavior described for Platypoecilus, i.e., WZ type (if scs
inherit:~nc~
; but ses-linked factor 12 was not sonsistent..
T h e gold Pl:ttypoecilus, onc tylic! .Kosswig W C ~ , nltliougli having fins ant1
1,xc.k somewhnt red, docs not contain tlie dominant sex-linked factor H , for
red b o d - color (Fraser itnil Gordon, in press of Genetks). The seeondarp red,
IIC‘U’ f:ietnr Ibf for rcd fiiis, wlieir brought int,o eombinrition with Xipllopliorus
factors, is intensified in F,. R.f resembles R phenot.ypic:ally, h i t is tmsilp di8t.inguisIied even when Rf i s intensified. Rf Ixis not us ?-et lieen sl~own in our
vxprimeiits t,o be sex-liukcd.
Ta our txwk-crosses, two :iutosomnI genes were t.estec1: St, for stippling, :uid 0,
for one-spot on c:iudal peduncle, toget.her wi.t.11 t.wo sex-linked genes, B and 8p
:issoei:itetl with the W cliromosome. Platypoeeilus (WlIx,,Z, Stst 00)by F,
Il.?l)ri(l 8 (Z, Z, 51, Rtst no) gavi?: females, 11 red-sI.’otted-stippled and 4 redspotted ; males, 4 stippled-onc-spotted, 4 st.ippler1, 1 one-spotted, nnd 1 recessive.
Other back-erosscs were made.
The h:iek-erosses show stability of tlrc WEsl, combina.tiou ancl simple mcndelian
inheritance of t.he autosomnl factors.
fO. j l l i t l f r_n7e Jisaiort
in Ertrronfmtr a u s .
BOBEKTC. RHODES,Ninory TJniversity.
Typical binary fission in IIeteronemn arus is langitudinal. The reservoir system
is halved, dividing from its posteriad region, ncar the anteriorly migrated nucleus.
Uoubt is held a s to the method of perpetunting the two flagcllae, but tlie oltlw
oncs probably persist, one going to each daughter organism and two new ones
originating by division of the basal granules. The old staborgan or mouth is,
liowcver, loosened, 1)asses posterind, and is resorbcd, while new oiies :ire diffcrentiated from near the dividing reservoir opening.
Ti1 multiple fission, two, three, and sometimes four suecassire divisions of
uucle:ir and cytoplasmic structures are :iccomplishcd withont the complete scp:~
ABSTRACTS
109
ration of the cytoplasm of the daughter organismfi. I n some stages eight
reservoirs are found with only six nuclei, two nuclei having probably been
resorbed.
H. acus has been under continuous observation for eight years, and only once
has multiple fission occurred, and this under unusual environmental conditions.
We have not yet been able to induce i t again. This occurrence may. be abnormal
and these somatellae largely monster forms ; but whatever its explanation, it
has not been previously recorded, so f a r as we know. The reduplication of
reservoirs, flagellae, and mouth parts is significant, in that the daughter or
newly originated cytoplasmic organelles are usually dirertly associated with
nuclear division.
41. Heritability of the effects of ultraviolet arul znfrared waves upon. the f i S S w S
rate within the clone of Purameciwn caudatwrn. AUSTIN R. MIDDLETON, Uni-
versity of Louisville.
Of sixty Paramecium caudatum, all of the same generation from a single
animal, twenty were exposed to ultraviolet light for fifteen days; twenty to
infrared light for fifteen days, and twenty were cultivated as controls. The
medium used was %2 per cent Horlick’s malted milk, prepared with distilled
water. The fission rate was determined by bdanced selection. The animals
were ‘washed ’ daily.
The three groups were continued for a second fifteen-day period under control
conditions.
During exposure the ultraviolet group divided a t the average rate of 8.15
fissions per line during fifteen days, with a range of from 3 to 1 2 fissions per
line. During the following fifteen-day period they divided a t the rate of 6.85
fissions per line, with a range of from 0 to 10 fissions.
During exposure the infrared group dirided at the average rate of 30.15 fissions
per line, with a range of from 28 t o 32 fissions per line. During the following
fifteen-clay period they divided a t the average rate of 18.6 fissions per line,
with t~ range of from 11 to 16 fissions per line.
During the first fifteen-day period the control set divided a t the average
rate of 26.63 fissions per line, with a iange of 23 t o 31 fissions. During the
sccond fifteen-day period they divided tit the average rate of 13.3 fissions per
line, with a range of from 10 to 20 fissions per linc.
Therefore, in this clone, ultraviolet light apparently modified hereditarily the
fission rate.
42. Four-strand crossing over.
ALEXANDERWEINSTF:IN,University of ilhnesota.
Crossing over has been shown to occur as originally described by Janssens:
each chromosome is split lengthwise, but only two strands undergo interchange
a t any level. This necessitates a reexamination of the theory. The number of
points of crossing over in the original strmds of a tetrad and in the emerging
strands do not necessarily correspond with each other or with the number in the
tetrad as a whole. F o r example, a triple crossover tetrad might result in strands,
none of which was more than a double crossover; and a triple crossover strand
might result from a tetrad in which no original strand had crossed over a t more
than two points. The true frequency of crossing over for either strands or
tetrads would on certain assumptions be-
110
AMERICAN SOCIETY OF ZOOLOGISTS
This formuh would, in general, give values of crossing over different from
the ordinary ones; but the theory of linear arrangement would remain valid.
One type of eoincidenre would on certain assumptions remain invariant; but
otlirr types would not. The application of the formula to experiment:il (kit:(
(including ordinary cases and cases involving non-disjunction, attached X ' 8 , and
polrploids) makes possible a test of the assumption on which it is based and
slinws that the :issociation of strands in crossing over is not a matter of pnw
rhance.
H E M A N L. IBSE?: AND 1 ~ .11). BUSHNELI,, KansaN
,C;t:tt.e Agricult.ura1 College.
In 102.1. me began our attempts to duplieate the work of Guper hy treating
r:tbbit females (and males) for tlie purpose of affecting t.he eyes of their offspring. Ten females were. injected with rabbit anti-lens serum obtained from.
liens ; they producad fifby-eight normal-eyed offspring and one with a slight
elondiness a t the base of a lens (observed with an ophthalmoscope). I n the
reniaini.ng experimeribs one or both eyes of tlie females, and in certain cases bot.11
eyes of tlic ni:iles, were needleil. When only the females' eyes were needled,
t.liere w r e 1.30 offspring produced, all with normal eyes. When both parents had
t.heir eyes needled, fifty-five of the offspring were norma.1-eyed a.nd one had il
sni:ill spot on tlie surface of each eorliea near t,lie crnt,er of t.he pupil (vi.sil.)leto
thc! naked rye). Xany of the iiormal-eyed .offspring from treated parents were
1n:ttt:d. The records on their 1.58 descendants show t.h:it all of t.liem mere normal-
43. E!ye def'c'cls i n rabbilx.
eyeti.
A t about the timc the above exyerinient.~were begun, two animal8 with not.ic:cbly defec-tire eyes were born in tlie Iaboratorp from untreated stock. Duriiig
the progress of the cxperinients three more of similar parentage 'cv(1re born.
ii
Oiie of t.lic latter was produced when
:i defeetive-.eyed male was mated to his
~ ~ o r . r n : ~ ~ -sistm.
e y c ~ l All of the firr :thove mentiont?ii were much niore noticeably
tlefrct.ire than the two obtn,ined from treated stock.
3J. Twiwniaff in scmc fresh-water s w i l s .
I'enns y 1.r-a11is..
.EDWARD
I). CRaan, IJnivtrrsity of
The object. af this investigation WRR t.o gain iiiformat.ion on the question o f
nion-ovul:u or Iii-ovular origin of twills. The maximum numlwr of vitelli, or
t!ml)ryos, found in a single egg W:IS two in the J a p snail (Viviparus malleatus),
Plrysa sq-ii, iind P. ancillaria : fivr in the Potomac snail (V. contectoides) ;
riglit in l~yi1111:telt p:ilustris, ltiid forty-sir in I,. st,:igiiilliv nppressa. Over 200
polyvitelline Lj-miia.ea eggs wcre incdiated to adva.nced stages or used in brcctling experiments without obta;ining a siilgle mirrored-image, or sinistral, inr1iridu:il
or aiiy intliciitioii that laying tliese eggs is a lieritablc character. I n L. Y.
ilppressa tlie peleentage of polyvitclline to normti1 eggs was 273 : 19,863 ; in L.
palustris, 15: 6939 (in another instanw, 2.7: 65 cc. of 'dry' egg masses), and
in Physa sayii, 2 : 9061. The abiioniial ~ g g swere studied txtire :i,nd in sections.
There are two instances in which two f u w d mat.ure vit.elli, in stages before the
first eleav:ige, were found. The presence of polar bodies on 1)ot.h fused ritelli
slinwvx that (w:h of thcse poteutktl conjoint4 twins arose from two o m . Stiitiics
ABSTRACTS
111
of whole and sectioned eggs show that maturation in each vitellus was normal
and that clea.vage was quite as independent as in normal eggs. There is no
evidence for mon-ovular origin of the twins studied.
45. The detcmination of identity in twins. S. J. HOLNES,University of Calif ornia.
The determinat,ion of identity in twins cannot be made with much probability
from any one character or even by an enumeration of points of resemblance
unless these are of an exceptional kind. I n order to secure a more reliable
index of identity, the measurements of particular parts in each pair of twins
were reduced to a quotient by dividing the smaller by the larger measurement.
The nearer this quotient approaches unity the closer the resemblanee of the
twins in the trait in question. Quotients were calculat,ed for thirteen characteristics t.hat were measured. Then all of these quotients were multiplied
together t.o secure a general index .of resemblancc. This procedure gives weight
to all factors involved, and at the same time it tends t o compensate, to a
certain extent., for any unusual difference in the measurements of any one characteristic.
Applying the test. of this c,omposite coefficient of resemblance t o a group
of twins makes it apparent t.liat t.he several pairs tend t o fa.11 into two fairly
contrasted categories. I n early years there is litt,le overlapping of the two
groups, but the differences become less sharp as the twins increase in age. By
the use of this coefficient one may ascertain from the extent of divergence a.ccompanying age something of the relative potency of environ.menta1 factors i n
the production of t.he similarities and dissimilarities between human beings.
46. Sea determination and sex-ratio determination in Sciara. CH.~RLESW. METZ,
Department of Genetics, Carnegie 1nst.itution of Washington.
I n some species of Sciara, pair matings regularly give unisexual’ progenies and
in other species ‘bisexual’ progenies. Genetic experiment.s on former type show
that female is responsible for the sex ratio. Female-producing female regularly
gives female-producing and male-producing daught,ers in equal numbers, suggesting the hypot.hesis that genetic constitutions are as follows : female-producing
female, Aa; male-producing female, a a ; male, aa. This is supported by the
fact that ‘exceptional’ females from. male progenies are male producers (twentytwo tested.)
Genetic evidence from sex-linked muta.nt character in S. coprophila indicat.es
presence of sex-chromosome pnir-XX’ female XY male. Hence 6ex is presumably ‘determined’ by sperms, of which each male produces b0t.h Ginds. Since
females give ‘ unisexual’ progenies and since preliminary egg counts indicate
absence of selective mortalit-y, evidence suggests presence of selective fertilization
--eggs of female-producing females being susceptible t.o fertilization by X
bearing sperms only, and vice versa.
As previously noted, cytological study of several species of Sciara shows that
males typically have two more chromosomes t.han females-the
large ‘sexlimited’ chromosomes. These apparently pass int.0 all sperms. I n production
of fema.les they are presuma.hly eliminated a t or after fertilization. That they
are not primary agent.s in sex determination is indica.ted.by genetic dat.a mentioned above and by the fact that in cytological material of one species recently
studied they are lacking.
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AMERICAN SOCIETY OF ZOOLOGISTS
.17.The establishment of races of pigeons charucteriEed by h r g e or small thyroirrs.
O ~ ( : A KRIDDLE,Carnegie Institution of Washington.
J t was previously report.ed that a t least. two ‘sma.11 thyroid’ and t.wo ‘large
thyroid ’ races had been est.ablished. Those results have now been extended t.0
include four races of each type. Through four t o six generations the liealt.lly
ilitlividuals of these races o r strains 1i:ivc satisfactorily maint:iinetl their thyroid
size a t a. chrwacteristic. level. It is tliouglit that the numerous difficulties attending a st.udy of the heritability’ of thyroid size have been adequately eliniin:it.ed
in our st.udy of twenty-four stra.ins of ring doves.
The fact that ‘thyroid ra.ces’ have been formed is in itself evidence that genetic,
f i ~ c t ~ fr os r thyroid size do exist.. Actditionxl evidence is now av:dnble from
crosscs of the various raccs. Large thyroid x large t,hyroitl yields large tliyroids
in F,. Small thyroid x small t.hyroid gives small thyroids in F,. Large thyroid
x sins11 or intermediate thyroid gives thyroids of intermediate size in F,. Some
further evidence is obtained from smaller numbers of F, and E’,. Questions of
tloniinnnce and of t,hc iiuniber of genet,ic factors involved require further study.
48. Stzldies
PAImvm,
071
AND
pigeon, hybrids. I . Aberrant sex ratios. L. J. COLE, T. 8.
AGNES ZEIMET,l7niversit.g o f Wiseonsill and University of
Texas.
Males :.ire commonly in exc,ess among hybrid anim:i,ls. Whitman : ~ n dRiddle
demonstrated this f o r pigeon hybrids, t,he proportion of males being in genersl
higher the wider t,he cross. Two principal explanat.ions have been offered: 1) sex
reversal and, 2 ) differential death rate of embryos. An attempt has been made
t o determine which is correct by studies of, 1) the dea.th rate of embryos; 2 ) sexlinked c,linra,cters, and, 3) chromosornttl reln tions. The present report deals
m:iinly with the death rate.
Domestic pigeon (Columba liria) 8 X Barbary dove (Streptopilia risoria) 9:
Of 1053 eggs, 575 arc reported as fertile. It was soon apparent that t.hcre wd.8
a very large death of embryos within the first. few days of development. Of those
continuing development, 222 :ire recorded ns males and three as females. I t i s
evident. t.liat because of the high early deat,li rate the possibility that the aberrant
sex ra.tio may be due t o different.ia.1mortality a.t. that time is not exc.luded.
Similar results were obtained from the cross of Chinese Pearlneck dow
(Spilopilia chinensis) 8 with Barbary dove 9, but in this c:we the relationship
is closer and tho excess of males produced is not so high.
In so far as it has been possible to check up on sex-linked ch:ir:icters, the
result,s are in accord with the interpret.ation t.hat the sex of the adult is wha.t
would ho expected on the genetic hasis. In other words, 110 evidence of SC?X
reversal ha.s been found.
’
4:J. The cvitical period for sex
C O ? l % r 0 1 and tlic poasiblc rriechan,ism of sex rleter?wination in Cludocera. AHTliUR M. BANTA,
Department of Genetics, Carnegie
Department of Zoology, UniverInstitution o f Washington, AND L. A. BROITN,
sity of Iowa.
Mot.hcrs crowded or otherwise subjected t o trcatments whicl~ m:~rkedl~lower
tlicir rate of developnient produce a large percentage of rn:~les anlong their
parthenogenetic offspring, whereas control mothers under norma.lly favora.l,le
conditions rarely produce any males. By beginning the crowding of the mothers
ABSTRACTS
113
at various times before egg laying and, on the other hand, by stopping the
crowding at similar intervals before egg laying, the critica.1 period for control
of sex was localized as a brief interval a t approximately four hours (at 20°C.)
before the eggs are laid. Previous to this period tho sex of the forthcoming
young is subjed to control measures; after this period sex is fixed. The critical
period is about three and one-half hours before t,ho spindle for the single
maturation division appears.
Control of sex in Cladocera is assumed to operate through a, sex-determining
mechanism, although such a mechanism is cytologically unknown in this group.
The possible type of sex-chromosome mechanism involved is discussed.
50. The [email protected] relation of the genes in the X-chromosome of Drosophila
mela.nogaster, referred to bar eye as base. A. H. HERSH,Wcstern Reserve
University.
By the use of the stock Xple (scute, echinus, crossveinless, cut, vermilion,
garnet, forked) and Zeleny 's low selected forked-bar stock, different combinations of the genes were madc by snita.ble matings. Tho mutant genes of the
Xple stock were added singly to forked bar, and cumulat,ively in the left-right
direction and also in the right-left direction on t.he chromosome. The facet
eount.8 of these fifteen stocks, raised a t 25"C., show that when t.he genes are added
singly cut and garnet are fairly strong minus modifiers of facet number, the
others are plus modifiers, crossveinless and vermilion notably so. When the
mutant genes are added cumulatively in the left-right direct.ion on the chromosome, bar eye becomes progressively larger until garnet is added. With the
addition of garnet, that ia in Xple bar, the eye is but slightly larger than in
forked bar. When tlie sections of the Xple chromosome are added to forked
bar in the right-left direction on the chromosome, t.he eye is smaller t.han in
forked bar, but becomes progressively larger, never, however, reaching the size
of forked bar until all are a.dded. The logarithm of the number of facets in
the dorsal lobe (x) is directly proportiona.1 to the logarithm of the number in
the ventral lobe (y) of the eye, that is, y = bxk. A comparison of the values
of b and k for the fifteen d s e r e n t aombination.s, calculated by a least-squares
met.hod, indicates that b shows an exponential decrease of about 44 per cent
for each 0.1 increa.se in k.
51. The inheritance of egg weight in domestic fowl. F. A. HAYS,Massachusetts
Agricultural College.
Studies are based on egg-weight records made on Rhode Island Red hens
hatched from 1924 t o 1927. The total number of birds upon which records are
available is 593.
The data indicat.e a very ra.pid increase in the weight of eggs laid by pullets
between the first egg laid and the egg w7eight of the same individuals by the
first of March. I t ha.s been shown to be possible to predict the probable egg
weight of birds during the spring hatching season by weighing the eggs in
November or December previous. Maximum egg weight. for the flock studied
appeared during the second laying year.
The market system of cla.ssifying eggs as 'standard' if they weigh 56.7 gra.ms
is essentially sound biologically, and birds laying such eggs differ genetically
from those laying small eggs.
THE ?LNA4T0YICALRECORD, VOL. 41, NO.
1
114
A4MEIZIChNSOCIETY O F ZOOLOGISTS
A dominant autosomal gene B for large eggs and a similar gene A for small
eggs appear to be concerned. Gene A is 1iypost:itic t.o R. Both show cumukttive
effects and no scx linkage is observed. Recessive birds h y very small eggs, not
differing greatly in size from those of Gallus bankiva.
5.1. T h e effect of loiig suBjecti.ox to constant temperatures q o ' n bur r y e of
Drosophila melaiwgaster. CHARLESZELENY,
Iiniversity of Illinois.
Under a constant temperature of 37°C. low selected and inbred bar of
Urosopllila melanogaster lias undergone a signific,nnt increase in cye-facet number
during t.lie course of 134 generations in sixty-seven months. During the same
time in fifty-one generat.ions a t 17' the sa.mc stock ha.s not changed in this
rcspeet. Rrciproesl transfers between the two temperature lines demonstratr,
however, that the temperaturc coefficients liavr decreased the same amount in
each.
53. The trmprrature eoefici.en,t and t e m r ~ ~ a t u r r - e f f e c t i vperiod
e
for win.# S ~ Z P
*lit. D ~ ~ . $ o p k i l a .WILLARDF. ~ T A N L E Y , University of Illinois.
(Introduced
bp Clia.rles Zeleny.)
The 1engt.h of vestigial wing varies directly with the temperature, but not in
direct. proporti.on. The length of t,lie normal, full wing varies invcrsely wit.li
tlie temperature. There is a distinct. sexual dimorphism of wing size in vestigial
wing w1iic.h is not consistently in one direction a.t. all t.empcratures, but is
depcndent upon the spec,ific temperatures. There is also a distinct sexual
diniorphism in per cent increase or decrease in wing length and in the sex
temperature c0efficient.s. This ma.rked sexual dimorphism sugge'sts t.he effect
of the various temperatures upon possible accessory factors on the X-chromosomes.
The t.cmpera.ture-offective period for vetlt.igi:il wing has been positive1.y demonstrated. There appea.rs t.o be R distinct sexual dimorphism as regards t.he
limits of the effect.ive period. The data indicate t.hat the effective periods a t
17" and 27" are a,pproximately in proportion t o the total developmental pc+ods
.at. those tempera.tures.
.54. The effect of temperature on infrabar ustl its heterozygotes.
Uriivcrsity of Illinois. (Introduced by Charles Zeleny.)
W. M. LUSE,
111 the bilr series of multiple allelomorplis of Drosophila melanogaster tlie
number of facets in the compound eye is dependent upon the temperature a t
which tlw larviae are grown. By means of f:i.c*et counts of flies tra.nsferret1 a t
stated intervals from one temperature to anot.lier, it was demonstrated in
homoxygous infrabnr and in infrahar b y bar heterozygotes that t.he effw.tive
period is confined to a comparatively short part of the lifr-cycle, corresponding
roughly to the lattrr half of the l m v s l period. A t a corresponding time in
development the imngina.1 discs of the adult eye are being formed so that it
.Lieems probable that the effective period for temperature is confined t.o tht.
prriod of nipid growth and multiplication of cells in the imaginal discs heforr
the onset of differentiation into the final form.
I n t.he hcterozygote the eeect. of t,emperature upon the acceleration of the
velocity of thc facet-forming process is very nearly the samc as the aceeleration
ill gciierd larval development produced by temperature. The major effrct of
t,empcrature on facet number is in this case upon the proc.esses that init.iat.e and
trrmin:lte the effective period. On the other hand, in infra.bar thr ma.jor effect
ABSTRACTS
115
of temperature upon facet number is the great. accelerat.ion in the facet-forming
process caused by this agent, while the differential effect. upon the processes
that initiate and terminate the effective period is slight.
55. The occurreme . of parthenogeiiesk i n the genus Clkrysan.themum.. E D ~ A R D
C. JEFFR.EY, Harvard University.
The genus Chrysanthcmuin has long been interesting on aceount both of t.he
cxtreme varLzbi1it.y of some of it.s species and also by reason of the polyploid?which it likewise exemplifies. Experimental and morphological studies of the
genus show that ma.ny of its species are parthenogenetic in their mode of reproduction. This mode of reproduction is quite commonly associabed in plants with
polyploidy, as, for example, the Canina section of roses. C. leucanthemum is
tetraploid and parthenogenetic and appears to typify other species of t.he genus
in respect t o the assockitim of polyphidy wit.h parthenogenesis.
56. Tkc i?&er.i.tawe of r.eprotlzlcti,vc: characteristics iir. Uaphnia longispinu..
KATHRYN
ORDWAY,Department of Grnctics, Carnegic Institution of W:rshington. (Introduc.ed by Arthur M. Bant,a.)
Iiiasmucli as parthenogenesis in Cladoceri~occ,urs without chromatic reduction,
all tlic members of a clone should have tbe same inheritance. On t,he other
1i:~nd, sexually produccd young wising from n rross between two cloiies show
heredita.ry differences in morphologictd cliar:ictcrist.ies. I n this study, mat.erB1
from Doctor Banta 'a laboratory was utilized t o obtain further data concerning
the inheritance of reproductive cha.ract.eristics in Daplmia longispina, Series of
mothers from sister clones (originating from hatched individuals from a cross
between two clones) were simult.aneously observed concerning their reproductive
characteristics as indicated by: 1) age at time of beginning reproduetion;
2 ) avera.ge number of young per brood; 3) aversge number of broods per
mother; 4) average interval between broods; 5) reproductive index (average
number of young per mother per day), etc. Several repetitions of such series
were made. I n all, in the three different groups of related clones studied, a
tot.al of 565 mot.hers and 78,825 young were observed, As judged b - the
averages obtained from t.he various measures employed, reproductive cha.ract.eristks me markedly uniform for the different members of a single clone (whet.lier
studied in only one or in different pa.rthenogenetic generations). On the other
hand, sister clones differ widely from one another; the same intraclonal eonstancy is a.pparent, but interclonal differences arc of wide range aud are of like
order and magnitude in different series of mothers eult.ured and studied simultaneously in several part.henogenetie generations. The data obtained indicat.e t.ha.t
reproductive characteristics (and longevity) in Daphnia longispina are determined
by genetic factors and that several such fact.ors are involved.
57. Zm7beritanct. in Mongolian idiocy. MADGETHUELOWMACKLIN, Universitv
of Western 0nt.ario Medical Seliool.
A c.ritica1 review of 1408 cases of Mongolian idiocy published in the 1iterat.ure
lends no support to the theories that environmental influences play an aetiologiral
r61e in its product,ion. Thus syphilis, mental suffering of the mother during
pregnancy, advanced age of either parent, especially the mother, a t the time of
conception, great difference between the ages of the parent or the number of
preceding pregnancies-none of thcse has any part, iii wusing this dise:tsc.
116
AMERICAN SOCIETY OF ZOOLOGISTS
IIeredity i s the causative factor-a
statement borne out by the study of the
owurrence of Mongolian idiocy in twins. It is not dependent. upon the presence
of :I pair of unit recessive factors, :AS has been stated, but is dependent. upon
:A coniples grouping of factors, presumably recessive.
$8. Somc cffects of the waxy gene in m.ai2e on f a t mieta.bolism. FREDA. ABEGG.
Flcniington, Kew Jersey. (Introduced by B. A. Brink.)
A more complete determination of the specific effects of the w:ixy gene on
reserves in maize grain and pollen would seem to be a prerequisite in establishing
the basic physiological activities of t.I& heritable element during devclopnicnt.
The evidcncr a.s cited indicates that the waxy gene modifies the f a t metabolism
of maize endosperm and that this gene is not limited in it.s sphere of action t o
c.I~:ingesin carbohpdrate nietabolism. The crude fat yield of lion-waxy endo.
sperm tissue proved to be 1.05 per cent; that of related waxy endosperm tissue,
1.5 per cent. The correspoiiding embryo tissues gave crude oil yields of 34.0
and 34.2 per eent, respectively. Thc average acid value of the crude fat. from
non-waxy cndosperm tissue was found to be 45 and t.liat of closel>-related wa.xy,
8 2 . I n the same stock of rmterial the averagc acid value of non-waxy embryo
crude oil was 4.21 and that of waxy, 4.16. The avera.ge saponification value
uf non-waxy endosperm crude fat. was found to be 177 and that of wary, 200.
Related ester values were 1.17 and 100, respectively. Non-waxy and waxy pollen
are nesrly equal in crude fat. content and difler little in ae.id values. Marked
tliff ercnces betwecn t.liese t,ypes arc characteristic of ether extracts from endosperm tissues only. I n some ma.nner the waxp gene a p p r e n t l y reduces tho
s p t h e t i c power of waxy endosperm lipme, hence the acid n l u e of the wary
endosperm crude fat is higher than that of the non-waxy.
,59. Di.uersities determined b y intrinsic and rxtriirsir co%t7ition8 in Sterostomzcm
acau.rint.um (not?. spec.), W i t h special referenee to their inheritance. T. M.
SOKNEBORN,
Rational Rescarch Council Fellow, Johns Hopkins University.
(Introduced by H. S. Jennings.)
This rhabdoeoel, reproducing ascxmlly, reveals intrinsic intIividua.1 differemes
ilcterminerl by the position in t,lie diain of zooids. A series of successiw niiterior
produc.ts of reproduet.ion exhibits a course of st.ruct,ural a.nd physiological changes
terniiiiatiiig in death ; a series of suecessivc posteriors undergoes neither such
changes nor death. The series of successive anteriors map be considered a. single
parent which a.ges and dies aft.er budding off numerous zooids from its posterior
cwd. P:irents differ from their offspring by budcling more slowly (comp:tred
on the same dates) and by dying sooner.
'Difkrences (of extrinsic origin) due t.o t.he action of dilute (0.0025 per cent)
lrad acetat.e on single individuals have been undemonstrable. Rwults of action
of the lead acctat.c on a succession of generat.ions are: 1) an increa.se in the
time to pi*otIuce succeeding generations ; 2) the production of structural abIiormalities. Tho action is cumulative (that is, inherited) from gcnera.tion to
gcncration during treatment..
.4fter removal to normal eondit~ions,st.ructurally al)norma,l individuals produced
in this way and otliers arising from aging parents under norma.1 conditions have
the following fates: most,, I) die or, 2 ) become normal; a faw, 3 ) retain thcir
i t hnorinality permanently.
The progeny of abnorinals are : generally, 1 ) normal ;
s o l ~ ~ ~ ~ t i l 2n )e s ,recipients of the pi1~11ti11abnorinslity by pseudo-inheritsnee ;
ABSTRACTS
117
rarely (not at all, among the progeny of aging normals), 3 ) identically like the
parents, forming tl new biotype.
tail, a mutation in the house mouse. HILRKISON
R. HUNTAND DOROTHY
PERMAB,
Michigan State College.
Two males showing this mutation were found in an albino stock secured
originally from Dr. W. E. C”astle. Eighteen flexed-tailed descendents of these
two males were mated with numerous normal-tailed mice. All of the 316 F,’s
mere normal, showing that tlie mutation is recessive. The F2’scomprised 423
normal males, 487 normal females, 49 flexed-tailed males, and 83 flexed-tailed
females-a total of 1042. The F, ratio is 6.9 normals: 1.0 flexed-tailed. Eight
crosses of flexed x flexed 1i:~ve produced GO young, all of tlicm flexed-tailed.
Back crosses are being made between F, females and their flexed-tailed inale
parents. An experimentally confirmed explanation is still being sought for the
peculiar F, ratio.
The character varies considerably. I n all cases the tail is permancntly rigid
owr a varying portion of its length, this stiffness being particularly conspicuous
proximally. The rigidity may be accompanied by permanent V-shapcd, U-shaped,
spjrd, etc., flexures, though sometimes the character may be identified only by
the inflexibility of a limited section of the tail. Further studies of the mutation
are in progress.
60. Flrxed
L. G. RARTH,University of Chicago. (Introduced by L. V. Heilbrunn.)
X-ray treatment of males of Drosopliila produccs a deviation in the sex ratio
of their progeny in the direction of more sons when tlic malcs are mated with
normal females. This dcriation from a 1: 1 ratio amounts to 6.7 times the
probable error. When the x-rayed males are mated with females haring attached
X-chromosomes, a deviation from a 1: 1 sex ratio of 13.4 times the probable error
is obtained. I n this mating more daughters arc produced than sons. The two
results arc consistent and serve as a check on each other, for in the first easc
the sons arc deterniined by the union of a Y sperm and an X egg, while in tlic
latter mating tlie daughters IIYC deterniincd by thc TT sperm and a n X X egg.
Thus in both cases there are more individuals resulting from fertilization by
Y sperm than X sperm. Therefore, there exists a differential susceptihilitp of
the X and Y sperm t o x-rays, resulting in a deficit of functional X sperm.
G1. T k r e f r c t of %-rays on the spermatozoa of llrosophblu.
62. Blood relationship with%%the order
Rodentia. R. A . HICKS, Vniversity of
Michigan. (Introduced by C. C. Little.)
Jn his classic study of phylogeny by means of precipitating antisera, ATuttal left
untouched the problem of the blood relationship of the rodents. The present
serological study of the four species of mice, Mus musculus, Mus wagneri, Mus
facroensis, and the aapanese waltzing mouse of the genus Mus was begun with
an attempt to produce precipitating antisera in pigeons, using tlie serum or
muscle extracts of these rodents as antigens. In spite of all modifications. in
manncr of treatment of the birds, the study of 200 pigeons has not given an
antiserum which would differentiate these mice. At present the pigeon may be
ronsidercd unsuited for the production of precipitating :intisera.
Recently, acting upon the suggestion of Dr. F. G. ATovy and following the
work of Uhlenhutli and Weidanz (’09) and R. Trommsdorf (’09) rabbits liave
118
AMERICAN SOCIETY OF ZOOLOGISTS
bren immunized against the serum of Mus musculus. Precipitating antisera
have been obtcLined from these rabbits a n d have been found t o be specific within
the order Rodentia.
Thr r;ibbit has been demonstrated to I J ~free from natural mouse or rat
Iirccipitin and is suitable f o r the prodnetion of these antibodies. The four
species of mice studied fall into two groups serologically distinct, one being
N u s mnsculus and Mus fneroensis and the other ,Japanese wsltzer and Mus
wagneri. Inside either of the two groups it has not been found possible to inake
F J ~ I Vserological distinction.
C. Smo?ia, J . J. BITTYER,
hSU ARTHUR
63. Malignancy and inbrertling. LEONELL
M. CLOUDNAN,University of Michigsn.
Several years ago many i n d i v i d d s of a moderately inbred and relatively
honiogrneons stock of micr (Biigg albino) gave rise t o spontaneous tumors. The
diagnoses, altliough the tumors varied slightly in histological appearance, werr
mostly carcinoma. Thesr tumors failed t o grow in any other individuals (a
large number of Bagg albino mice were used f o r inoculation). I n comparison,
spontaneous tumors arising in the highly inbred dilute brown stock will grow
i n 100 per cent of the dBr strain, even at the initial inoculation, although the
degree of malignancy of (1% tumors is estimated histologically t o be lower thsn
that of the albino tumors. It is therefore hard to see what genrtic relationship
reallg exists between malignanry and tr:insplmihihility. Since the first results,
the process of inbreeding Bagg albinos has been continued. Recently, upon
testing out transplants of new spontnneous tumors arising in thitt str:iin, w r
find that they will grow in 100 per cent of inoculated individuals, cren at the
initial iiiocul.ition. Thus it would seem that grnetic factors, segregated during
the process of inbreeding, undoubtedly play n very important rOle not only in
tlre itssumption of malignancy by, but also i n the transplantabi1it.i of, tlict tumor
(,ell.
64. Tlw iiifiurnce of envilanwient on. the inheritamr of two characters in
~ ~ , o s o p ~ l iXILDRED
~a.
HOG'SRICIIARUS,University of Oklahoma.
E g g s of ten muhint races of Drosopliila mrlanogastcr wrre subjected to temperatures of 10" and 14°C. From the eggs so treated 5.5 per cent of abnormal
flies hatched, but tlre new characters did not persist t o any extent in Rubsequent
generations. Further experimentntion with the descendants of these treated
stocks brought out frequrntly two c1mr:icteristics. Selection of thew two, abnormal abdomen and blistered wings, developed rektirely small percentages of
the :ilmorm:ilitirs. An attempt was made t o determine the influence of the
environment on these two characters. Treatment with cold temperatures brought
out a much larger per cent of blistercd wings, but failed to affect abnormal
:Ibdomen. Wlien the eggs were developed under moderately moist conditions, the
;ilmorni:iI abdomen stock produced a much greater number of flies with the
:ibnormalitS. Abnormal abdomen is not sex-linked ; blistered wings is apparently
wx-linked :ind semilethal.
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