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 ct s 510
v+cts 1
v+ ct+ s 14
v+ ct+ s+ 500
v+cts+ 73
v ct s+ 20
v ct+ s 81
v ct+ s+ 1
Total 1200

Determine the order of these genes on the chromosome.

Calculate the map distances between the genes.

Determine the coefficient of coincidence and the interference among these genes.