8. Three recessive mutations in D. melanogaster-roughoid (ru, small rough eyes), javelin (jv, cylindrical bristles), and sepia eyes (se, dark brown eyes) - are linked. A three-point cross was carried out and the following progeny obtained: a. Determine the order of the genes on the chromosome. b. Determine which progeny contain single crossovers and which contain double crossovers, and indicate where among the genes the crossovers occurred. c. Calculate the map distances among the genes. d. Calculate the coefficient of coincidence and interference among the genes. .