Hair and Eye Color
In Scandinavia, people who do not have blond hair and blue eyes stand out. A study considered hair and eye color in families from Copenhagen, Denmark. In each of 50 families, one partner has the common blond hair and blue eyes, while the other partner has brown hair and brown eyes (parents). For the brown-haired, brown-eyed partners, each has a parent that looks like them and a parent that is blue-eyed and blond-haired (grandparents). In total, the 50 families have 260 children with the following phenotype frequencies (children):
Phenotype # of children
Brown hair, blue eyes 4
Blond hair, brown eyes 6
Brown hair, brown eyes 120
Blond hair, blue eyes 130
Brown hair (H) is dominant to blond hair (h), and brown eyes (B) are dominant to blue eyes (b).
A. What is the genotype or genotypes of the blond-haired, blue eyed parents?
B. Are the genes for these traits linked or unlinked? Justify your answer?
C. Explain or diagram how the brown-haired, blue-eyed and blond-haired, brown-eyed children arose.