Question

1. Consider a pedigree where two parents affected with the Leber congenital amaurosis(LCA) have six children and all six are normal. The simplest explanation for this observation can be explained by _ ?

2.  Condition in which the phenotypic effects of a gene’s alleles are fully and simultaneously expressed in the heterozygote is called ?

Answer 1

1. If both the parents are affected it means that the Leber congenital amaurosis(LCA) can be either dominant or recessive trait ,but when their children are normal it means both the parents are heterozygous for the said trait .Now how all their children are normal it is because all the children carry the normal alleles of the trait one normal allele from each parent. It is possible by chance.

2. Condition in which the phenotypic effects of a gene’s alleles are fully and simultaneously expressed in the heterozygote is called Dominance.