A stock homozygous for three recessive autosomal genes, a, b,and c, not necessarily linked on the same chromosome, ismated to a stock homozygous for their dominant wild-typealleles. F1 females are then backcrossed to males of thehomozygous recessive parental stock and the
following cross results are observed:
Phenotype Number Phenotype Number
a bc 42 a b+ 6
+ ++ 48 + +c 4
a ++ 46 a +c 5
+ b+ 44 + bc 5
1. Which of these genes are linked?
2. What is the recombination frequency between the linkedgenes?