Question

Assertion : In pigeons, females are heterogametic and males are homogametic.
Reason : In pigeons, females have $ZW$ sex chromosomes and males have $ZZ$ sex chromosomes.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

In pigeons, $ZW$-$ZZ$ type of sex determination mechanism is found. In this type, 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 $Z$.