In Drosophila, ebony body (e) and rough eyes(ro) are encoded by autosomal recessive alleles for genes found on chromosome 3; they are separated by 20cM. The recessive allele for the gene that encodes curly wings(cy) is found on chromosome 2 and assorts independently of e and ro. When an e+ ro+/e ro cy+/cy fly is testcrossed, what proportion of the offspring will have ebony body, smooth eyes and curly wings?
