Time mapping is performed in a cross involving the genes his, leu, mal, and xyl. The recipient cells were auxotrophic for all four genes. After 25 minutes, mating was interrupted with the following...

Time mapping is performed in a cross involving the genes

his, leu, mal, and xyl. The recipient cells were auxotrophic

for all four genes. After 25 minutes, mating was interrupted

with the following results in recipient cells. Diagram the

positions of these genes relative to the origin (O) of the F

factor and to one another.

(a) 90% were xyl+

(b) 80% were mal+

(c) 20% were his+

(d) none were leu+