Question

Which of the following is not true about NHEJ?

(a) In most of the cases, it is associated with loss of genetic material

(b) Ku is present at a concentration as high as 400000 per cell

(c) It strand invasion looks for micro-homology regions

(d) The 3’overhang chewed up to chi sequence invades to search for homology

This question was addressed to me during an internship interview.

I would like to ask this question from Repair of DNA Damage: Recombinational and Bypass in chapter DNA Mutation, DNA Repair, Transposable Elements of Cytogenetics

Answer 1

Right answer is (d) The 3’overhang chewed up to chi sequence invades to search for homology

The best I can explain: In NHEJ to reduce the loss of genetic information and for a quicker search of homology domains the 3’ over hand is only 4 nt long. This increases the probability of fining micro homology region as well as prevents loss.