Question

The white-tailed deer, Odocoileus virginianus, is common in the Eastern United States. Most deer have reddish brown fur, but occasionally a deer may be born with a genetic condition known as albinism which results in white fur. Albinism is caused by the inheritance of two recessive alleles for the production of coloration pigments. If an albino deer is born to two parents who each have normal fur coloration, what conclusion may be drawn about the genotypes of the parent deer?

Answer 1

The parents are heterozygous, meaning that each parent carries both a dominant and a recessive fur gene. The dominant gene makes them phenotypically express brown fur, but allows them to pass on the recessive gene to their offspring.

Answer 2

Both parents must be heterozygous for the coloration gene. Since one allele is inherited from each parent and the albino deer has two recessive alleles for coloration, one recessive allele must have come from each parent. Since both parents are normal in color, each must be heterozygous for this gene.