Question

some of the genes for making proteins allowing people to see color are found on the x chromosome. the trait of being color blind is recessive. if a man is color blind, who gave him the genes for the trait?

Answer 1

A colorblind man inherited the trait from his mother. Females need two copies of the gene to be colorblind. Female carriers have a 50% chance of passing colorblindness to their sons.

Step-by-step explanation:

Color blindness is a sex-linked recessive trait, which means it is usually carried on the X chromosome. Males, having only one X chromosome, express color blindness if that X chromosome contains the recessive gene. Therefore, a colorblind man must have inherited the trait from his mother, who had at least one X chromosome carrying the colorblindness gene.

A female would need to inherit two genes for colorblindness, one from each parent, to be colorblind, which is very unlikely since the trait is recessive. Females with one normal vision allele and one colorblindness allele are carriers; they do not express the trait but can pass it to their offspring. If a carrier female has children with a non-colorblind male, there is a 50% chance her sons would be colorblind and a 50% chance her daughters would be carriers.