PATHOLOGY MCQ
GENETICS AND DISEASE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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If a male has an recessive gene on the X chromosome for a sex-linked trait such as colorblindness, where did he get the gene from?
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His father
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His mother
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Either A or B
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None of the above
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Explanation:
Detailed explanation-1: -Colour blindness is a X-linked recessive disorder. Son gets its X-chromosome from mother; since the male is affected, he has got the Xc allele from his mother.
Detailed explanation-2: -This is due to the fact that males possess only a single X chromosome, and therefore require only one mutated X in order to be affected. Women possess two X chromosomes, and thus must receive two of the mutated recessive X chromosomes (one from each parent).
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