mtl,polA,and xyl are bacterial genes that can be transmitted using an Hfr strain.An interrupted mating experiment resulted in xyl exconjugants appearing at 7 minutes and reaching maximum level by 30 minutes.The mtl gene function exconjugants appeared at 11 minutes and leveled off at 80% maximum by about 33 minutes,while polA did not appear until 24 minutes into the experiment and then only slowly rose to about 30%.Which of the following shows the gene order with the insertion site (arrow)location correctly?
A)xyl mtl polA → B)polA mtl xyl → C)mtl xyl polA → D)mtl polA xyl → E)None of these