The colonies of recombinat bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of :
Insertional inactivation of alphagalactosidase in recombinant bacteria
Inactivation of glycosidase enzyme in recombinant bacteria
Insertional inactivation of alphagalactosidase in non-recombinant bacteria
Non-recombinant bacteria containing betagalactosidase
