Another gene in Drosophila determines wing length. The dominant wild-type allele of this gene produces long wings; a recessive allele produces vestigial (short) wings. A female that is truebreeding for red eyes and long wings is mated with a male that has purple eyes and vestigial wings. F1 females are then crossed with purple-eyed, vestigial-winged males. From this second cross, a total of 600 offspring are obtained with the following combinations of traits:

252 with red eyes and long wings

276 with purple eyes and vestigial wings

42 with red eyes and vestigial wings

30 with purple eyes and long wings

Are the genes linked, unlinked, or sex-linked? If they are linked, how many map units separate them on the chromosome?