An X-linked recessive gene almost never has a counterpart on the Y chromosome. Therefore excessive traits on the X chromosome

Question

Biology

Jonathon Ellis

18 July, 08:23

An X-linked recessive gene almost never has a counterpart on the Y chromosome. Therefore excessive traits on the X chromosome

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Answers (1)

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Jeffrey Mcclure · Answer 1

The propositions are:

A. affect both sons and daughters equally.

B. affect sons more than daughters.

C. affect daughters more than sons.

D. have no effect on neither sons nor daughters.

The right answer is B) affect sons more than daughters.

The diseases whose gene is located on the X chromosome are most often transmitted in the X-linked recessive mode.

*Boys with only one X chromosome, so this one will express itself completely. If he has a mutated X chromosome (as in the case of hemophilia A and B), he will necessarily present the disease.

*Whereas girls who have two X chromosomes, they must have two mutated X chromosomes to express the disease, which is a very rare case (I remind you that we are talking about a recessive disease), that is why girls are less affected than sons. if they have only one sick gene, they will then carry the disease to their descendence without expressing it.