Assume that these phenotypes are caused by two independently assorting genes. Choose gene and allele symbols and define them. H l b. Write the genotypes of the parents for each case. Some of the answers have more than one possibility so include all possible crosses. These two genes assort independently of each other because the gametes from the double heterozygous parent are formed in equal amounts.
Pigmentation is normal elsewhere than in the eye.
Its likely to be recessive to show up in children of parents who are both unaffected. If it is an autosomal recessive, then I.1 and I.2 would both have to be heterozygotes, as would II.6. The likelihood of two hets marrying each other in two successive generations of the family is very small if the trait is rare and there is no inbreeding, so it is more likely to be X-linked, which assumes that people marrying into the family have only the normal alllele of the trait. Write the genotypes of all family members according to your hypothesis. Write directly on the pedigree.