In interrupted mating experiments using an Hfr strain in E. coli, you find that two genes, bio and arg, are transferred at about the same time. A third gene, pab is transferred slightly later. In order to determine the gene order, you mate an Hfr strain that is pab+ bio+ arg+ with an F- strain that is pab- bio- arg-, select 3000 recombinant pab+ clones from the recipient strain, and test them for the presence of arg+ and bio+. You obtain the following results:
pab+ bio+ arg+: 2607 clones pab+ bio- arg+: 61 clones
pab+ bio+ arg-: 2 clones pab+ bio- arg-: 330 clones
Part A
What is the order of the three genes?