UNISEXUAL PROGENIES AND THE SEX CHROMOSOME MECHANISM IN SCIARA

Abstract

Evidence from Sciara coprophila Lint. indicates that sex of the individual and sex of the progeny as a whole are "determined" by sex chromosomes: X, X[image], and Y. The chromosome combinations are: (1) [male] XY; (2) [male]-producing [female] XX (homozygous for the X found in the [male]); (3) [female]-producing [female] XX[image]. X[image] differs from X in respect to the agent responsible for "sex of progeny." The X descends directly from mother to daughter; X passes back and forth between the [male] and both kinds of [female][female].