Chapter 6, Problem 19EQ

Three autosomal genes are linked along the same chromosome. The distance between gene A and B is $\text{7 mu,}$ the distance between B and C is $\text{11 mu,}$ and the distance between A and C is $\text{4 mu}\text{.}$ An individual that is AA bb CC was crossed to an individual that is $aaBBcc$ to produce heterozygous ${\text{F}}_{\text{1}}$ offspring. The ${\text{F}}_{\text{1}}$ offspring were then crossed to homozygous $aabbcc$ individuals to produce ${\text{F}}_{\text{2}}$ offspring.

A. Draw the arrangement of the alleles on the chromosomes in the parents and in the ${\text{F}}_{\text{1}}$ offspring.

B. Where would a crossover have to occur to produce an ${\text{F}}_{\text{2}}$ offspring that was heterozygous for all three genes?

C. If we assume that no double crossovers occur, what percentage of ${\text{F}}_{\text{2}}$ offspring is likely to be homozygous for all three genes?