Question

Why are males heterogametic?

Answer 1

Hint: Heterogametic means sex chromosomes are not same in the species. In male sex chromosomes are X and Y then it is called as heterogametic. In female sex hormones have both X the it is called as the homogametic. Heterogametic is also called as the digametic sex. Human males are producing two types of sex chromosomes called X and Y.

Complete answer:
Gametes produced by the male are also the two types. One bearing the X chromosome and another one is Y. So males are said to be heterogametic. This type of heterogametic sex is present in the insects, reptiles, birds and animals. Platypus males are heterogametic but female is homogametic.
This type of heterogametic occurs in homogametic sex. It undergoes X chromosome inactivation in embryos. Heterogametic is the gender of an organism due to the presence of two different sex chromosome. Mammals and females are coming under the homogametic gender types and males are coming under the heterogametic gender. Sex determines only at the offspring. Haldane proposed the definition for heterogametic organism sex. Particular variable region on the X chromosome contains C or G. Sex abnormalities in male is called as Klinefelter syndrome (XXY).

Note:
In the offspring of two different animal’s races then one sex is absent, rare or sterile. So that type of sex is called as heterogametic. He did observation based on the fertility and viability of hybrids. So male DNA contains the chromosomes called X and Y. Y chromosome in male consists of around two hundred working genes. All X chromosomes have the same number of particular STR.