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 autosomal recessive trait (e.g.,Sickle cell anemia) ltbr. (c) Both parents of generation I are heterozygous `(i.e., Hb^(A) Hb^(S))` and carrier for the gene. The third child male and developed the trait so the genotype is homozygous recessive `(i.e., Hb^(A) Hb^(S))`. The fourth child is female an d carrier for the ene. Therefore, the genotype of fourth child is heterozygous `(i.e., Hb^(A) Hb^(S))`