Question

In ZZ/ZW system which of the following is true?

(a) All organisms have ZZ chromosome

(b) The chromosomes are shaped like Z

(c) Females have ZW constitution

(d) Male is heterozygous

The question was asked during an interview.

This key question is from Other Methods of Sex Determination topic in division Chromosomes and Sex Determination of Cytogenetics

Answer 1

The correct option is (c) Females have ZW constitution

The explanation is: ZZ/ZW sex determination system is much like XX/XY system. However, in this case male is homozygous ZZ and female is heterozygous ZW. In this case to avoid confusion different notation is used and not because of the shape.