For Hinaidori, only male samples were checked because the Hinaidori-specific SNP was positioned on chromosome Z and, in the chicken, females are the heterogametic (ZW) and males are homogametic
First, since the homogametic
sex in dipteran insects are female, a cross of X-linked recessive beating females with wild-type males will produce F1 progeny in which females are heterozygous and phenotypically wild-type and males that are hemizygous for the mutant recessive phenotype.
Therefore, females are homogametic
in that they just produce X-bearing gametes, and males are heterogametic, producing both X- or Y- bearing gametes.
For some fish species, all-male populations can be produced by crossing homogametic
males (YY) with normal females (XX) (10,11), whereas all females are produced by crossing sex-reversed females (XX; physiological male) with normal females (XX) (28).
In species in which the male is of the "X-Y" type, the male is heterogametic, the female homogametic
Their importance is also suggested by theoretical work on Haldane's rule, which states that the viability or fertility of the heterogametic sex is more likely than that of the homogametic
sex to be reduced in hybrids (Haldane 1922).
This may be due to the sex in papaya which is determined by a single gene with three alleles, in which males and hermaphrodites are heterogametic, while females are homogametic