AP BIOLOGY

Detailed explanation-1: -The 23rd chromosome (pair) is made up of two parts – either two X chromosomes if you are female or an X and a Y chromosome if you are male. The ‘gene’ which causes (inherited, red and green types of) colour blindness is found only on the X chromosome.

Detailed explanation-2: -The genes that can give you red-green color blindness are passed down on the X chromosome. Since it’s passed down on the X chromosome, red-green color blindness is more common in men. This is because: Males have only 1 X chromosome, from their mother.

Detailed explanation-3: -Most commonly, color blindness is inherited as a recessive trait on the X chromosome. This is known in genetics as X-linked recessive inheritance.

Detailed explanation-4: -X-linked red-color blindness is a recessive trait. Females heterozygous for this trait have normal vision. The color perception defect manifests itself in females only when it is inherited from both parents.

Detailed explanation-5: -X-linked recessive inheritance refers to genetic conditions associated with mutations in genes on the X chromosome. A male carrying such a mutation will be affected, because he carries only one X chromosome. A female carrying a mutation in one gene, with a normal gene on the other X chromosome, is generally unaffected.