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Genetics

The gene for albinism is recessive, and therefore the child will not show signs of albinism unless it receives the recessive allele from both parents. Approximately 1 out of every 70 people is a carrier for albinism. Therefore the probability of two carriers reproducing is one in 4900, or .02%. Even if they do reproduce, there is only 1 in 4 chance that their child will be albinistic. This type of genetic disorder is referred to as autosomal recessive.

The ocular albinistic gene (affecting the eyes) is X-linked, meaning the trait is attached only to the X-chromosome. This tells us that men can only inherit the disease from their mothers, because there mother donates the X-chromosome, while the father donates a Y-chromosome. A man with an affected X, his only X, will show signs of the disease. Women, on ther other hand, can become a carrier by inheriting one affected X-chromosome from either their father or mother. To become ocular albinistic, they will need to receive an affected chromosome from each parent.^[1]

http://www.mayoclinic.com/health/medical/IM00849

This picture represents how an autosomal recessive gene is transfered from parent to offspring. Both of the parents are carriers (for albinism in our case), and the probability of having in albinistic child, the pink child, is one in four. The probability of having a carrier child, the green and pink children, is one in two. Finally, the probability of having a normal, non-carrier child, all green, is also one in four.^[2]