What category is color blindness in?1. Chromosomal abnormalities 2. Single gene disorders 3. Multifactorial (complex, polygenic) disorders 4. Teratogenic disorders
Since colorblindness can be due to different gene mutations, located on different chromosomes, the correct answer would be choice 1--chromosomal abnormalities. Color-blindness is inherited on the X chromosome as a sex-linked recessive condition. It is passed usually from mother's to sons. If the female has an X with the normal gene and her other X is a carrier for the colorblind gene, half of her son's will inherit the normal X and have normal color vision, and the other half will inherit the X with the colorblind gene and be color blind. That is because males have only 1 X chromosome and their Y chromosome has no effect on color vision. Females have 2 X chromosomes. If one is normal and the other has the colorblind gene, they will only be carriers and not have colorblindness. However, chromosomes 2, 7, and 8 also have genes that affect color vision. Since there are several different gene mutations involved, on different chromosomes, depending on whether the colorblindness is yellow-blue, red-green, or the absence of color vision, the answer is chromosome abnormalities.