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प्रश्न
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
उत्तर
- 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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संबंधित प्रश्न
Which of the following is an example of ZW – ZZ type of mechanism of sex determination?
The person A has only B chromosomes in all its gametes. On the other hand, another person C has chromosome D in half of gametes and chromosome E in the other half of gametes. When chromosomes B and D combine during fertilisation, a female zygote results. On the other hand, combination of B and E chromosomes produces a male zygote.
(a) What are chromosomes (i) B (ii) D, and (iii) E?
(b) Out of B, D and E, which two chromosomes are of the same type?
(c) Which chromosome is smaller in size?
(d) What is the general name of chromosomes such as B and E?
(e) Out of the two persons A and C, which one is (i) male, and (ii) female?
Name any two genetic in humans.
Kavitha gave birth to a female baby. Her family members say that she can give birth to only female babies because of her family history. Is the statement given by her family members true? Justify your answer.
Grasshopper is an example of XO type of sex determination in which the males have ______.
If a normal cell of the human body contains 46 pairs of chromosomes then the numbers of chromosomes in a sex cell of a human being is most likely to be ______
Select the incorrect statement
Which of the following statements is not true with respect to variation?
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
How is the sex of a newborn individual determined in different species of animals? Give three examples to support your answer.
