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Question
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
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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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RELATED QUESTIONS
Write the types of sex-determination mechanisms the following crosses show. Give an example of each type.
(i) Female XX with Male XO
(ii) Female ZW with Male ZZ
Fill in the following blank with suitable word :
Genes always work in ................ .
The two versions of a trait (character) which are brought in by the male and female gametes are situated on :
(a) copies of the same chromosome
(b) sex chromosomes
(c) two different chromosomes
(d) any chromosomes
Choose the correct answer:
Males have more chances of suffering from sex-linked disease because of ___________
Short Answer Question.
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The number of pairs of sex chromosomes in the zygote of a human being is ______
A man with blood group A marries a woman having blood group O. What will be the blood group of the child?
The maleness of a child is determined by
