Grandparents and parents do not have dimples on the chin, but the grandson does.

Grandparents and parents do not have dimples on the chin, but the grandson does. There is a hypothesis that dimples on the chin are inherited. How to explain this phenomenon.

This phenomenon can be explained by the recessiveness of the gene that causes the development of the chin dimple. Genes that are recessive appear externally only if they are found together in the human genotype, that is, if a person is homozygous for the gene for a trait that is recessive.

A person can carry the gene for a recessive trait in a latent, latent form, as part of a heterozygous genotype.

For example, we denote the gene for a dimple on the chin as a, and the gene for the absence of such a dimple as A.

If both parents are heterozygous – Aa, then they will not have dimples on their chins, but they will pass on the gene for the recessive trait (a) to the offspring.

Two such parents may have a child with the aa genotype and a corresponding dimple on the chin.