NEET BIOLOGY

Detailed explanation-1: -In humans, the allele for dimples (D) is dominant. The allele for not having dimples (d) is recessive.

Detailed explanation-2: -The allele for dimples (D) is dominant to the allele for no dimples (d). A man heterozygous for dimples marries a woman who is also heterozygous for dimples. Offspring phenotypes: The allele for hitchhiker’s thumb (h) is recessive to straight thumb (H).

Detailed explanation-3: -Cheek Dimples are a very common characteristic in people. One allele for the gene that codes for cheek dimples is given the symbol “D”. The other allele that codes for no dimples is given the symbol “d”. A person that has cheek dimples will have a genotype of either DD (homozygous) or Dd (heterozygous).

Detailed explanation-4: -If the genotype of the father would have been heterozygous, there are chances that one of the children would have born without the dimples. Therefore, the father and the mother have homozygous genotypes DD and dd, respectively. All the children, as shown in the cross above, will have heterozygous genotype, Dd.