Previous studies on fluted pumpkin reported an XY system of sex chromosomes with
homogametic XX female and heterogametic XY male [6].
In a minority of dioecious plants, sex determination depends on sex chromosomes, usually an XY system, in which males are heterogametic (XY) and females are
homogametic (XX) [1-3].
In birds and reptiles, a
homogametic male or a ZW system uses dosage compensation to initiate the sex differentiation cascade.
Higher possible genomic mortality of heterogametic (ZW) females compared with
homogametic males (ZZ) allows the males of these species to offer sacrifice to save the females, which has the responsibility of rearing the brood.
chinensis through synaptonemal complex (SC) analysis, which suggested that the male shrimp might be the
homogametic sex [12].
mori, are designated ZW for the heterogametic female and ZZ for the
homogametic male (Yokoyama et al., 2003; Nagaraju, 1996).
In birds, females are the heterogametic sex (ZW) and males are
homogametic (ZZ) (Ellegren 1996).
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 (ZZ).
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).