Detection of recombination DNA from Trp*cells Agar lacking Agar lacking tryptophan tryptophan Trp-cells No growth Trpcells Recombinants form colonies A selective medium can be used to detect rare genetic recombinants among a large population of nonrecombinants.On the selective medium only the rare recombinants form coloniesChen Feng, Shanghai Jiao Tong University Detection of recombination A selective medium can be used to detect rare genetic recombinants among a large population of nonrecombinants.On the selective medium only the rare recombinants form colonies