Question

Probability of incorporation of a gene P is 0.2 and the probability of incorporation of another gene is 0.1. The probability of both being incorporated is seen experimentally to be equal to 0.1. What is our inference?

(a) Both the genes are incorporated randomly

(b) The genes are linked

(c) The bacteria has a preference for the two gene

(d) It was just an artifact

I had been asked this question during an interview.

This intriguing question originated from Gene Mapping in Bacteria by Transformation in chapter Genomics : The Mapping and Sequencing of Genomes of Cytogenetics

Answer 1

Right choice is (b) The genes are linked

For explanation I would say: The probability of incorporation of both should be theoretically 0.2X0.1= 0.02. But experimentally it is found to be 0.1 which is the same as that of 2^nd gene. Thus these genes are completely linked i.e. whenever b is incorporated a is incorporated as well.