Albinism (lack of skin pigmentation) is caused by a recessive allele. A man and woman, both pigmented, have an albino child together. What is the genotype of the albino child? What is the genotype of the parents?

1 Answer
Dec 6, 2015

If we use the letter ''A'' for the normal trait, and ''a'' for albinism, then the parents both must be Aa, and the child aa.


Since ais is whylbinism is a recessive trait, then it does not show unless it is homozygous in the individual, and this is why the kid is aa. Since the parents are both pigmented, then they must both have the A allele, and since their kid is aa, then s/he must have had these alleles from his parents, one a each.