Question

What is the role of Rec BCD in DSB repair?

(a) It helps in strand invasion

(b) It chews off the flap

(c) It helps to generate 3’ overhang

(d) It helps by aligning the two homologous chromosomes

I have been asked this question in homework.

My doubt is from Repair of DNA Damage: Recombinational and Bypass topic in section DNA Mutation, DNA Repair, Transposable Elements of Cytogenetics

Answer 1

Correct option is (c) It helps to generate 3’ overhang

Easy explanation: Rec BCD acts as an exonuclease that selectively chews off the 5’ end of DNA to generate a 3’ overhang. This is necessary for strand invasion by this 3’ overhang which brings about recombination repair.