Question

The male fruit fly and female fowl are heterogametic while the female fruit fly and the male fowl are homogametic. Why are they called so?

Answer 1

In Drosophila, females have two X chromosomes (XX), while males have one X chromosome and one distinct Y chromosome (XY). Conversely, in fowls, females are heterogametic with ZW chromosomes, and males are homogametic with ZZ chromosomes. Thus, female fowls (ZW) produce two types of gametes, whereas male fowls (ZZ) produce one type. This contrasts with Drosophila, where males are heterogametic (XY) and females are homogametic (XX).