Brown eyes is dominant to light eyes. Mr. O'Ryan has blue (light) eyes. Mrs. O'Ryan is heterozygous for brown eyes. What are the color possibilities of their son?

Mr. and Mrs. O'Ryan are likely to have children with brown or blue eyes, with a 50:50 chance.

Explanation:

According to the genotypes of the parents, a cross can be made and the probability of the offspring having blue or brown eyes can be determined.

Genotypes:

Mr. O'Ryan bb (homozygous recessive).

Mrs. O'Ryan Bb (heterozygous).

Bb X bb

Alelles B b

b Bb bb

b Bb bb

The result of the crossing is:

Heterozygous Bb descendants with a brown-eyed phenotype (50%). Homozygous recessive descendants bb, with a blue-eyed phenotype (50%).

Mr. and Mrs. O'Ryan have the possibility to have both brown - and blue-eyed offspring.