A heterozygous, but phenotypically wild-type fruit fly (gray body color and normal wings) was mated to a black fly with vestigial wings. The...

A heterozygous, but phenotypically wild-type fruit fly (gray body color and normal wings) was mated to a black fly with vestigial wings. The offspring had the following phenotypic distribution: wild type, 720; black-vestigial, 780; black-normal, 280; gray-vestigial, 220. What conclusion is likely from these results?