Essential Genetics 6th Edition by Daniel Hartl

Exercise 18

A bacterial geneticist hopes to map genes a through g by means of interrupted-mating experiments using three Hfr strains designated X, Y, and Z. From the data in the accompanying table, showing times of entry in minutes, deduce the genetic map of the markers a through g. Position the genes in correct order on a circle that represents the entire E. coli chromosome, 100 minutes in circumference, and show the distance in minutes between adjacent pairs of genes. Show the insertion point and orientation of the F plasmid in each Hfr strain.