L012 Calculate the probability of genotypes and phenotypes in dihybrid crosses of sex linked traits mixed with autosomal traits In Drosophila yellow body color is caused by a sex-linked recessive allele and brown eye color is an autosomal recessive trait. A phenotypically normal female fly. heterozygous for both genes, is crossed to a male with normal body color and brown eyes. What proportion of their offspring should have yellow body color and brown eyes? 1/4 1/2 1/3 1/8.