Red hair (R gene) and freckles (F gene) are controlled by two different genes that are tightly linked on chromosome 16. Red hair is recessive to brown hair, whereas having freckles is a dominant trait. Although people with red hair and freckles often have blue eyes, the eye color gene (E gene) is on chromosome 15 and thus sorts independently from the other two genes. Blue eyes are recessive to brown eyes. An individual with genotype RRffEE mates with an individual with genotype rrFFee.
1) What is the genotypic and phenotypic ratio of the offspring? Show your work with a Punnett Square.
2) One of these offspring grows up and marries a man who is rrffee. What is the phenotypic ratio of their offspring (i.e., the grandoffspring of the original parents)? Show your work with a Punnett Square.
3) Suppose all three genes are very tightly linked. What would the phenotypic ratio of the grandoffspring be under this scenario? Show your work using a Punnett Square.