In the cells of all human females, one X chromosome is inactivated. The opsin1 g

Question

In the cells of all human females, one X chromosome is inactivated. The opsin1 gene is on the X chromosome and is expressed in the retinal cells of the eye. Mutations in this gene cause the recessive trait of colorblindness. Most women who have one mutant allele of the opsin1 gene and one normal allele of the opsin1 gene (they are heterozygous) can still see color. What is the most likely explanation for this finding? Question 20 options:

A) If the active X has the mutant allele of opsin1 gene, the inactive X with the normal allele will be reactivated.

B) Any mutations in the opsin1 gene on the active X can be corrected through genetic exchange (recombination) with the inactive X.

C) Some retinal cells will have an active X with the mutant allele of the opsin1 gene, and some will have an active X with the normal allele of the opsin1 gene.

D) The X with the mutant allele of the opsin1 gene is more likely to be inactivated because of the opsin1 mutation.

Explanation / Answer

Answer:

C) Some retinal cells will have an active X with the mutant allele of the opsin1 gene, and some will have an active X with the normal allele of the opsin1 gene.

Explanation:

Some retinal cells will have an active X with the mutant allele of the opsin1 gene, and some will have an active X with the normal allele of the opsin1 gene. The cells with an active normal opsin 1 gene will allow females to see color as the normal gene is dominant over mutant gene.

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