Localization, which would indicate that vast regions of the chromosomes would not recombine, usually occurs in the heterogametic
sex as predicted by the Haldane-Huxley rule (Fig.
In addition, the absence of mutant green thorax phenotype in the heterogametic
males indicates that gt is autosomal.
Therefore, females are homogametic in that they just produce X-bearing gametes, and males are heterogametic
, producing both X- or Y- bearing gametes.
The genetically male tadpoles were produced from crossings between males (ZZ) of one local population, in which females are the heterogametic
sex, and females (XX) of another local population, in which males are the heterogametic
The large size of the cells, the nature of the valves, the absence of flagellate forms (except in some heterogametic
forms) and the diploid nature of the vegetative cells has meant that the diatoms have been considered the zygotes of other chrysophytes.
Similarly, male-killing Wolbachia have been observed in both male and female heterogametic
In species in which the male is of the "X-Y" type, the male is heterogametic
, the female homogametic.
Although that can not provide a universal explanation for greater male mortality, because greater male mortality is also found in sexually size dimorphic birds, where females are the heterogametic
sex (Charnov 1982), it could be a contributing factor.
The consistent appearance of hybrid male sterility early in the evolution of two genetically diverging species (where the heterogametic
sex is male) has marked it as the first step in the process of speciation (Coyne and Orr 1989).
1] for dominant and codominant traits and linked markers during hybridization and development of multiple-parent heterogeneous and heterogametic
Androgens are required life-long in males--from the heterogametic
sexual differentiation in utero, through secondary sexual development during puberty (where they are the major determinants of extragenital sexual dimorphism), to the establishment and the maintenance of adult sexual function and fertility.
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 [24, 25].