In humans, a dimple in the chin is a dominant characteristic. a. a man who does not have a chin dimple has children with a woman with a chin dimple whose mother lacked the dimple. what proportion of their children would be expected to have a chin dimple? b. a man with a chin dimple and a woman who lacks the dimple produce a child who lacks a dimple. what is the man's genotype? c. a man with a chin dimple and a non-dimpled woman produce eight children, all having the chin dimple. can you be certain of the man's genotype? why or why not? what genotype is more likely, and why?

A.

Let's assign the dominant allele for dimples as - D - and the recessive as – d.

Based on the description, the woman must be heterozygous (Dd) for the dimple allele while the man is homozygous recessive (dd).

For the woman, her mother never had dimples meaning she was homozygous recessive (dd). This means the woman got a dominant allele from his father’s side and one recessive from the mother.

The man and the woman will, therefore, have the chances of bearing offspring as shown in the punnet square below;

50% will have dimples while 50% will not.

B.

The same as above (and punnet square attached) because there is merely a switch of genotypes between the sexes as per the description.

C.

Yes because in such case, the man is homozygous dominant (DD) for dimple allele. This way all offspring will be heterozygous dominant meaning they'll all have dimples. See the next punnet square (attached)