Question

Study the given pedigree chart and answer the queation that follow.

(a) In the trait recessive or dominant ?
(b) Is the trait sex-linked or autosomal ?
(c) Give the genotypes of the parants in generation I and of their third and fourth child in generation.

Answer 1

(a) The trait is recessive (b) The trait is not sex - linked because it appears in male and in female.
(c) Both parents of Generation -I are heterozygous ( i.e., `Hb^(A)Hb^(S)`) and carrier for the gene. The 3rd child is male and developed the trait so the genotype is homozygous recessive (i.e., `Hb^(S), Hb^(S)`). The fourth child is female and carrier for the gene `(Hb^(A)Hb^(S))`