Question

In an experiment you have a U-Tube with two strains of bacteria in two arms. In one arm the bacteria are Gal+ and His-, in other the strain is Gal- and His+. If the two arms are joined by a membrane that doesn’t allow bacterial cells to pass to opposite site what will you observe when you plate each arm bacterial strain on minimal media?

(a) None will grow

(b) Some colonies seen in right arm

(c) Some colonies seen in left arm

(d) Some colonies seen in both arms

This question was posed to me in class test.

My question is from Gene Mapping in Bacteria by Transformation in division Genomics : The Mapping and Sequencing of Genomes of Cytogenetics

Answer 1

Correct answer is (d) Some colonies seen in both arms

The best I can explain: Here the transfer of gene is mainly due to transformation. Although the bacterial cells couldn’t come in physical contact yet their nucleic acids could flow with the liquid to other arm and it can be incorporated by the bacterial cells in the other arm.