How Does a Person Inherit This Disorder?

A person inherits colorblindness through the X gene. This is always passed down by the mother, so you can blame her if you have it. The reason she might not show symptoms is because female's 23rd chromosome is XX while males are XY. If females have the colorblindness gene in one X, then she has the other X (the dominant allele) to back her up. That is why males are more often colorblind than females, they don't have another X to back them up.

 For example, my biological father ( I am adopted) was not colorblind but my mother was heterozygous (click for definition) for the gene, so she had one bad X and one good X. I got passed this bad X.

Oddly enough, colorblindness can also be caused by diseases, medications, or chemicals. However, we will keep this blog about inherited colorblindness.

Sources acquired from the Genetic Disorders Library
Image per Biology Corner