Question

In birds with the ZZ-ZW sex-determining system, the W chromosome of a female is inherited from the bird's ____:

a) Father
b) Mother
c) Grandparent
d) Sibling

Answer 1

In the ZZ-ZW sex-determining system seen in birds, females with the ZW combination inherit the W chromosome from their mother, since the mother has both Z and W chromosomes, while fathers possess only Z chromosomes.

Step-by-step explanation:

In birds with the ZZ-ZW sex-determining system, the W chromosome of a female is inherited from the bird's mother. This system is distinct from the mammalian system where the female is typically XX and the male XY. In birds, the sex-determining system works such that females are ZW (heterozygotic) and males are ZZ (homozygotic). The W chromosome is critical in sex determination, suggesting that females can only inherit it from their mothers, who possess both Z and W chromosome while fathers only have Z chromosomes. This is akin to how human males inherit the Y chromosome from their fathers.