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Question
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
Solution
- The sex chromosomes in birds are determined as Z and W. The male is homomorphic (ZZ) and the female is heteromorphic (ZW).
- W chromosome carries female sex-determining genes and duplication of Z chromosome indicates male sex.
- So, in case of chicks, the sex is determined by the egg and not by the sperms.
- The difference between sex mechanisms of humans.
- birds is that the male is homomorphic (ZZ) and the female is heteromorphic (ZW) in birds, whereas the male is heteromorphic (XY) and female is homomorphic (XX) in humans.
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Sex of an individual is determined by different factors in various species. Some animals rely entirely on the environmental ones, while in some other animals the individuals can change their sex during their life time indicating that sex of some species is not genetically determined. However in human beings, the sex of an individual is largely determined genetically.
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OR
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