In Drosophila melanogaster, cut wings (ct) is recessive to normal wings (ct), sable body (s) is recessive to gray body (s'), and vermilion eyes (v) is recessive to red eyes (v). All three recessive mutations are X-linked. A female fly with cut wings, sable body, and vermilion eyes is crossed to a male with normal wings, gray body, and red eyes. The F1 females produced by this cross were mated with cut, sable, vermilion males in a testcross. The following are the progeny resulting from the testcross. V V V V V V V V vt ct ct ct ct ct ct ct Total S S S S S S S S 510 1 14 500 73 20 81 1 1200 a) Determine the order of these genes on the chromosome. b) Calculate the map distances between the genes. c) Determine the coefficient of coincidence and the interference among these genes.