2-Female Drosophila heterozygous for three recessive mutations e (ebony body), st (scarlet eyes), and ss (spineless bristles) were testcrossed, and the following progeny were obtained:
Phenotype Number
wild-type 134 ebony 16 ebony, scarlet 136 ebony, spineless 694 ebony, scarlet, spineless 156 scarlet 736 scarlet, spineless 20 spineless 108
(a) What indicates that the genes are linked? 1 mark
(b) What was the genotype of the original heterozygous females? 1 mark
(c) What is the order of the genes? 1 mark
(d) What is the map distance between e and st? 1 mark
(e) Between e and ss? 1 mark? 1 mark
(f) What is the coefficient of coincidence? 1 mark
(g) Calculate the interference? 1 mark
(h) Diagram the crosses in this experiment. 1 mark