Question

You have two circular chromosomes that are undergoing homologous recombination. The resolution of Holliday intermediate will give rise to _________________

(a) 4 smaller circular chromosomes

(b) 2 smaller circular chromosomes

(c) One larger circular chromosome or two smaller chromosomes

(d) 3 same sized circular chromosome

This question was posed to me during an interview.

This intriguing question comes from Repair of DNA Damage: Recombinational and Bypass in portion DNA Mutation, DNA Repair, Transposable Elements of Cytogenetics

Answer 1

Right answer is (c) One larger circular chromosome or two smaller chromosomes

For explanation I would say: Resolution of Holliday intermediate will give rise to two smaller chromosomes if resolved in one way. And it can also give rise to one larger chromosome if it is resolved in the other way, but both of these have 50% chance and it doesn’t occur together.