Question

a boy is color blind (sex-linked recessive) and has a continuous hairline (autosomal recessive). which could be the genotype of his mother

Answer 1

The possible genotype of the boy's mother could be XAXaY or XaXaY. Girls can have one X chromosome with the colorblind gene and one X chromosome with a normal gene for color vision, making them carriers. The mother could have inherited a colorblindness allele from her father and a normal allele from her mother.

Step-by-step explanation:

The possible genotype of the boy's mother could be XAXaY or XaXaY. Boys only have one X chromosome, so if it carries the gene for colorblindness (Xa), they will be colorblind. Girls, on the other hand, have two X chromosomes, so they can have one X chromosome with the colorblind gene and one X chromosome with a normal gene for color vision.

Since colorblindness is recessive, the dominant normal gene will mask the recessive colorblind gene in females. Therefore, females with one colorblindness allele and one normal allele are referred to as carriers. They carry the allele but do not express it. In this case, the mother of the colorblind boy could be a carrier who inherited an X chromosome with the colorblind gene from her father and a normal X chromosome from her mother.