An albino married a known carrier for albinism. What is the probability of their having an albino child?
To determine the probability of the albino couple having an albino child, we need to understand the inheritance pattern of the albinism trait. Albinism is typically an autosomal recessive inherited disorder, meaning that both parents must pass on the recessive gene for their child to have albinism.
Let's assign some labels to simplify the explanation:
- Albino parent 1 (AP1) = The albino individual
- Albino parent 2 (AP2) = The known carrier for albinism
Both AP1 and AP2 have the albinism trait, as AP1 is albino and AP2 is a carrier. Since albinism is a recessive trait, both AP1 and AP2 must have at least one copy of the recessive gene.
Let's assume that the albino gene is represented by 'a' (recessive) and the normal gene is represented by 'A' (dominant).
AP1 genotype: aa (two copies of the albinism gene)
AP2 genotype: Aa (one copy of the albinism gene)
When the couple has a child, each parent randomly passes down one of their copies of the gene. The possible combinations are as follows:
AP1 aa
AP2 Aa
Possible gene combinations for the child:
aa (albino)
Aa (carrier)
Therefore, there is a 50% probability that their child will be albino (aa) and a 50% probability that the child will be a carrier (Aa).
So, the probability of the albino couple having an albino child is 50%.