Question

The events listed below are all necessary for homologous recombination to occur properly:

A. Holliday junction cut and ligated
B. strand displacement 2
C. DNA ligation and heteroduplex formation 3
D. double-strand breaking by endonucleases 1
E. branch migration4
F. enoduclease nicking, ligation and recombinant duplex separation
Which of the following is the correct order of events during homologous recombination?
A) E, B, F, D, C, A
B) B, E, F, D, C, A
C) C. E, F. B, D, A
D) D, B, C, E, A, F

Answer 1

D) D, B, C, E, A, F

Explanation:

Homologous recombination (HR) is a DNA repair pathway that consists of the exchange between two identical (or very similar) DNA regions. The steps of HR are: 1-Strand exchange, which refers to the pairing between broken DNA regions; 2-Strand invasion in order to provide a DNA crossover (Holliday junction); 3- Branch migration, capable of extending the heteroduplex regions far away from DNA crossover, 4-Resolution, where Holliday junction is resolved by cleavage of the junctions; 5- In the last step, a DNA ligase enables the joining of DNA strands.