abstracts of papers presented at the 1962 meetings - Genetics

ABSTRACTS 987
+/Su-V and Su-V/Su-V parents were coppared in detail for frequency and intensity of eye
pigmentation, using y w/Y sons of YS w yYLy+/Y 8 8 x y w/y WO 0. Dp(z~F)*~4.~~~, a short
insertion from the X into IIIL proximal heterochromatin, provided an autosomally inherited wm
locus. Heads were squashed singly and chromatographed. Absorption by drosopterin was measured
with Densichron model 4-51-4, totaling 3384 measurements. In summary: (1) all three
genotypes are easily distinguishable, +/+ being the most variegated, Su-V/Su-V the least; (2)
father’s Su-V genotype is irrelevant to offspring phenotype; (3) offspring of Su-V/Su-V mothers
are less variegated than those of +/Su-V mothers, and the latter offspring are less variegated
than those of +/+ mothers; (4) a paternally-derived Dp variegates less than a maternallyderived
Dp. All three of the foregoing effective conditions jointly determine the phenotype of a
fly.-A previously reported anomaly in the parental-source-of-Dp effect, (4), in one Dp stock
(“Dpf”) is attributable to the presence of Su-V on its Dp chromosome. “Dpf” and recombinants
from Su-V +/+ Dp behave identically. (Supported by the U.S. Public Health Service.)
STADLER, JANICE, and JOHN W. GOWEN, Iowa State University, Ames, Iowa: Patterns of reproductivity
of different strains of mice under continuous irradiation.-Latent effects of acute
irradiations, dependent on genotype and dose, may not be manifest until the latter part of life.
Similar delayed effects are of concern should they accumulate in successive generations of mice
that are under frequent irradiations even though the daily exposure dosages may be small. Mice
from several inbred strains have been exposed to gama ray radiation from a CoGO source
throughout their lifetimes and the lifetimes of their descendants in each successive generation.
The gamma radiation has been given at eight different dose levels over exposure periods averaging
22 hours per day. Sterility resulted from dosages of over 3r per day. Adequate reproduction
to maintain the germ line is obtained from mice exposed to 0.6 to 2.0r per day. Up to 14 generations
have been reared under continous radiation. Following the original single pair nonbrother
by sister mating exposed, all successive generations have been bred within litter matings.
Four strains thus far have attained ten generations in this atmosphere of continuous radiation.
Samples of progeny of the tenth generation litters are under test for life-span, fertility, viability
of young, disease resistance, dominant and recessive visibles, and sterility. The performance of
these lines will be discussed. (This work has received assistance from Contract AT(11-1) from
the Atomic Energy Commission. Journal Paper No. 5-4362 of the Iowa Agricultural and Home
Economics Experiment Station, Ames, Iowa. Project No. 1180, 1187.)
STENIUS, CHRISTINA, LAWRENCE C. CHRISTIAN, and SUSUMU OHNO, City of Hope Medical
Center, Duarte, California: Chromosome complements of the turkey and the pheasant compared
with that of the chicken.-While the recovery of viable hydrids between two species indicates
their close taxonomical relationship, the sterility of the F, hybrids suggests, among other things,
structural differences between the chromosome complements. Indeed, a chromosome study on
horses, donkeys, and mules revealed a great number of morphological discrepancies between
the complements of horses and donkeys.-Since an intergeneric hybrid between Gallus domesticus
and Phasiunus colchicus and an interfamilial hybrid between Gallus domesticus and
Meleagris gallopauo have been reported, we undertook a study of the chromosome complements
of the pheasant and the turkey, comparing details with that of the domestic fowl of both sexes
at mitosis and meiosis. The autosomal complements of the three species have very little in common,
while the Z chromosomes are identical not only in size but in centromeric loci and pachytene
banding as well, as illustrated by the accompanying series of photomicrographs. (Supported
in part by a National Science Foundation grant C-17601.)
STRAUSS,
B. S., University of Chicago, Chicago, 111.: “Recouery” of DNA from the effects of
alkylation.-The transforming activity for linked histidine and indole loci of DNA extracted
from a methionine-requiring strain of B. subtilis is reduced about tenfold per unit of DNA by
treatment of cells, with 0.025 M methylmethanesulfonate (MMS) for 30 minutes at 37C. The