A woman with blond hair and a straight nose married a man with dark hair and a “Roman” nose.

A woman with blond hair and a straight nose married a man with dark hair and a “Roman” nose. Determine what kind of children can be born to these spouses, if you keep in mind that the man’s mother has the same phenotype as his wife, that is, with blond hair and a straight nose. (The gene for blond hair is recessive, and the “Roman” nose is dominant).

Let’s designate the gene for the development of light hair as b, then the gene for dark hair will be B. Let’s designate the gene that causes the development of the “Roman” nose as C, then the straight nose will be due to the gene c.

A woman with blond hair and a straight nose will be a digomozygote for recessive genes – bbcc, because only if the genotype is homozygous can these traits be realized phenotypically.

Since the man’s mother had the same genotype and produced only one type of germ cells – bc, she could only pass on genes for recessive traits to her son. Therefore, a dark-haired man with a “Roman” nose is diheterozygous – BbCc. It produces four types of sperm – bc, BC, Bc, bC.

This married couple may have the following offspring options:

children with blond hair and straight noses (bbcc) – 25%;

children with dark hair and a “Roman” nose (BbCc) – 25%;

children with dark hair and straight noses (Bbcc) – 25%;

children with blond hair and a “Roman” nose (bbCc) 25%.