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Question
Explain why generally only the male child suffers from colour blindness and not the female?
Solution
Colourblindness is caused by recessive genes which occur on the X chromosome.
Males have only one X chromosome. If there is a recessive gene present on the X chromosome, then the male will suffer from colour blindness.
Females have two X-chromosomes. It is highly unlikely that both X chromosomes carry abnormal genes. As a result, if one gene is abnormal and recessive, the normal gene present on the other X chromosome will mask its expression. Females are unlikely to suffer from colourblindness.
The following cases explain the sex-linked inheritance of colour blindness.
Case 1
Case 2
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RELATED QUESTIONS
Give technical terms for Repeated units of DNA molecule
Differentiate Between Haemophilia and Colour blindness.
A haemophilic man marries a carrier women. Find out the probability of their offsprings being haemophilic.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Colour blindness is a Y-linked character.
Haemophilia is more common in males because it is a ____________.
A marriage between a colourblind man and a normal woman produces ____________.
Identify the CORRECT statement from the following.
If a carrier woman marries a normal visioned man, what is the percentage possibility of sons being colourblind?
Types of sex- linked genes:
(Haemophilia, Ichthyosis, nephritis, Myopia, Hypertrichosis, Retinitis pigmentosa)
| Column 'A' | Column 'B' | |
| (1) | Completely X- linked genes | ______ |
| (2) | Completely Y- linked | ______ |
| (3) | Incompletely sex-linked genes | ______ |
