In Drosophila melanogaster there is a dominant allele for gray body color and a dominant allele of another gene for normal wings. The recessive alleles of the two genes result in black body color and vestigial wings respectively. Flies homozygous for gray body and normal wings were crossed with flies that had black bodies and vestigial wings. The F1 progeny were then testcrossed, with the following results: Gray body, normal wings: 236 Black body, vestigial wings: 253 Gray body, vestigial wings: 50 Black body, normal wings: 61 Would you say that these two genes are linked? If so, how many units apart are they on the chromosome?