Heterogametic Females

Heterogametic Females In this method of sex determination the females are heterogametic producing dissimilar gametes while males are homogametic producing similar gametes. To avoid confusion with the XX-XO and XX-XY types Y CHROMOSOME The human Y chromosome is only Mb in size with functional genes whereas X chromosomes are Mb in size with about , genes. XII Std Zoology Chapter XII Std Zoology Chapter Principles of Inheritance and Variation of sex determination, the alphabets ‘Z’ and ‘W’ are used here instead of X and Y respectively. Heterogametic females are of two types, ZO-ZZ type (eg. Moths, butterflies and domestic chickens) and ZW-ZZ type (eg. Gypsy moth, fishes, reptiles and birds).