Question

after incubation, your -pglo lb/amp plate has white colonies growing on it. you are positive that you added a sample from the -pglo tube to this plate. what can you conclude as possible explanations?

Answer 1

White colonies on an LB/amp plate with a -pglo indicate successful bacterial transformation with a plasmid conferring antibiotic resistance but no disruption to the lacZ gene.

Step-by-step explanation:

Presence of white colonies on the -pglo LB/amp plate suggests that the bacteria have taken up the plasmid without the gene of interest and have become antibiotic resistant. This happens when the bacterial transformation process is successful, but the lacZ gene on the plasmid was not disrupted by the insertion of foreign DNA.

Without the disruption, the enzyme beta-galactosidase is not produced, hence the colonies remain white rather than blue (which indicates a successful gene insertion). White colonies indicate the insertion of foreign DNA within the polylinker site, which disrupts the lacZ gene, resulting in the loss of beta-galactosidase activity. This confirms the presence of the DNA insert in the plasmid.