Explanation

ZW and ZZ Type of Sex Determination This mechanism operates in certain insects (butterflies and moths) and in vertebrates (fishes, reptiles and birds). The male has two homomorphic sex chromosomes (ZZ) and is homogametic and the female has two heteromorphic sex chromosomes (ZW) and is heterogametic. There are thus two types of eggs with Z and with W and only one type of sperms. i.e., each with Z [image:5c_image20.emf] WZ-ZZ types of sex determination