Question

Differentiate between ZZ and XY type of sex determination mechanism.

Answer 1

Sex determination is a type of biological system, which is used to determine the sexual characteristics of an organism, and most of the offspring which are formed from the sexual reproduction has two types of sexes, except in somewhere there are hermaphrodites.

Complete answer:
In the question, they asked about the difference if ZZ and XY type sex determination.

ZZ type of sex determination: This type of sex determination is commonly observed in the animals like fish, reptiles, etc, in those organisms, the sexual characteristic of the offspring is determined by females, because in those animals, females have a heteromorphic character where it produces two types of gametes namely ZW and ZZ, and these produced gametes are called as hetero gametes, and when coming to males they produce a single type of gamete, so sex determination in this organisms depends on females.

XY type of sex determination: this type of sex determination, is commonly observed in the humans, wherein the humans, males show the heteromorphism, and they produce hetero gametes because the sex chromosomes present in the male humans are XY, so in the gamete formation, they form some X gametes and some Y gametes, but when coming to females in the humans, they show homomorphism, the chromosomes of females are XX, so they only produce one type of egg, so in the production of offsprings, the sex determination majorly depends on the males, but not in the females.

Note: In some insects like moths there is a sex determination of ZZ/ZO type, which means that males have two Z chromosomes, while the female moths have only one Z chromosomes, here the sex determination is by a number of Z chromosomes.