Question

In an experiment you introduce your gene of interest in a wild type E. cloli genome using an episome. However, you fail to see the product protein being formed. What could be the possible reason for this?

(a) The gene was silenced

(b) The gene product was produced in negligible quantity

(c) The bacteria was in stress so it was not producing much protein

(d) The gene was excised out

The question was asked in an international level competition.

This intriguing question originated from Restriction Endonuclease in division Genomics : The Mapping and Sequencing of Genomes of Cytogenetics

Answer 1

Right option is (d) The gene was excised out

Easy explanation: While all the reasons stand a possibility of being true, under the experimental condition it might be due to the restriction enzyme cleaving out GOI considering it a virus. Thus, the E. coli strains need to be restriction deficient but methylation proficient.