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Question
What is Lyonisation?
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Solution
Lyonisation is a process of inactivation of one of the X chromosomes in some females.
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
Which of the following combinations of sex chromosomes produce a male child : XX or XY?
A normal cell of human body contains 23 pairs of chromosomes. The number of chromosomes in a sex cell (sperm or ovum) of a human being is most likely to be :
(a) 46
(b) 23
(c) 21
(d) 42
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?
Read the following statements and select the correct option.
i. If sperm containing Y chromosome fertilizes the ovum, then diploid zygote is formed that grows into a male child.
ii. If sperm containing X chromosome fertilizes ovum, then diploid zygote is formed, that grows into a female child.
Which type of sex determination is observed in honey bee?
In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosomes is/are ______.
- large chromosome
- small chromosome
- Y-chromosome
- X-chromosome
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 ______
How many types of gametes are produced by a human female?
What is the probability of a girl or a boy being born into a family? Justify your answer.
