Question

Study the given pedigree chart and answer the questions that follow:
(a) Is the trait recessive or dominant?
(b) Is the trait sex-linked or autosomal?
(c) Give the genotypes of the parents shown in generation $I$ and their third child shown in generation $II$ and the first grandchild shown in generation $III$.

Answer 1

a)The trait is a dominant one as all the generations are affected.

b)The trait is autosomal because both the sexes are equally affected.

c)If 'A' is the dominant allele for the trait and 'a' is the recessive allele,

The genotype of the generation 1 parent is -aa and Aa.

The genotype of a third child in the generation is- Aa.

The genotype of the first grandchild in -Aa.