Question

Study the pedigree chart given below showing the inheritance pattern of a human trait and answer the questions that follow:

(a) Give the genotype of the parents shown in generation I and of the son and daughter shown in generation II.

(b) Give the genotype of the daughters shown in generation III.

(c) Is the trait ***-linked or autosomal? Justify your answer.

Answer 1

(a) Genotype of the parents in generation I:

Male (Father) — Aa

Female (Mother) — Aa

Son (Generation II) — Aa

Daughter (Generation II) — aa

(b) Genotype of the daughters in generation III—Aa

(c) It is an autosomal trait, because if the -linked trait has to appear in the daughter (generation II), the father must have it; put he does not show the trait and so it is not -linked.