A single female heterozygous for orange eye-color and derived from a cross of unrelated parents was bred to one of its own orange sons. Descendants were inbred by sibling matings in different lines for ten generations with orange and wild type black eye-color retained in each line. Orange and black stocks were then derived and the orange females were crossed in various combinations with the black males. Total progeny counted were 56,913 females, 7,471 diploid males and 41,899 haploid males. Only two members of the single series of multiple sex alleles are to be expected because the entire population was derived from a single female. The data suggest an influence of maternal genotype exceeding that of paternal on viability of diploid males and also an increase in their viability due to heterosis. Diploid male viability as compared with that of females showed no association with sex ratio or with average numbers of haploid males or of females per fraternity. There were, however, eleven so-called mutant fr...
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