Color-blindness is a common sex-linked recessive trait in humans. If a woman is color blind, which is the most accurate statement about color-blind individuals in her family line?

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Correct Answer:C. Both of her parents, at least one of her mother’s parents, and at least one of her father’s parents had the gene.
If a woman is born color blind (a sex-linked recessive trait: XCXC), she must have a color blind father (XCY) who can donate one recessive X gene and a mother who was at least a carrier (XCXC, or XCX). The father must have received the color blindness allele from his mother. The mother must have had at least one parent with the color blindness allele.
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