cos ori amp eukaryotic DNA cos Sall Hindlll Package in vitro into bacteriophage A particles Infect E.coli and select for amp'transformants Ampr colonies carrying recombinant cosmids Amp O 0 0 amp 。 0 O 。 O 0 0 0 0 0 0 0 0 0 0 Hindlll 2626