Alleles are created when a single gene undergoes several distinct mutations. These alleles may have
different dominance relationships with one another; for example, there are three alleles coding for the
human blood groups, the IA, IB, and i alleles. Both the IA and IB alleles are dominant to the i allele, but IA and IB are codominant to each other.
A multiple-allele system has recently been discovered in the determination of hair coloring in a species of
wild rat. The rats are found to have one of three colors: brown, red, or white. Let B = the gene for brown
hair; b = the gene for red hair; and w = the gene for white hair. The results from nine experimental crosses
are shown below. The males and females in Crosses 1, 2, and 3 are all homozygous for hair color.
Based on the experimental results, what is the genotype of the male in Cross 6?