Alcohol and the sex ratio in mice.

Abstract

An animal heterozygous for a character produces two kinds of germ cells with respect to that character. Since these two classes of germ cells differ in their genetic potentialities, it is conceivable that they may also differ in their ability to react to varied environmental conditions. Critical tests of this question are difficult to devise, one of the best thus far being that introduced by Stockard 1 in his alcohol inhalation experiments. By use of Stockard's method evidence has been obtained which indicates that when alcohol is thus introduced into the tissue of the fowl, germ cells are differentially affected according to their general vigor, 2 as well as on the basis of some of their genetic differences. 3 In the mouse, in which the male is presumably heterozygous for the sex chromosomes, Bluhm 4 found a much higher sex ratio after administering alcohol to the male parent by subcutaneous injections. The difference was attributed to a differential effect on the two classes of sperm cells. Bluhm's work has been questioned 5 , 6 because of the low sex ratio in the controls (80 males: 100 females in a total of 965 young, as compared with a ratio of 122:100 among those sired by alcohol-injected fathers). The more recent data of Parkes 7 shows a wide seasonal variation in the sex ratio of mice which may help to explain the apparent discrepancy in Bluhm's results.

The present report covers three short experiments in which male mice were treated with alcohol fumes in the usual way. Cylindrical glass specimen jars of about 20 cm. diameter and 5.5 liters capacity were fitted with false bottoms of perforated paraffined wood supported on short metal legs.