In the following schematic drawing of a Holliday junction that undergoes branch migration, cutting at which combination of the sites a to d would generate a crossover?
A) a and b
B) a and c
C) a and d
D) b and c
E) b and d

Question

In the following schematic drawing of a Holliday junction that undergoes branch migration, cutting at which combination of the sites a to d would generate a crossover? 
A) a and b 
B) a and c 
C) a and d 
D) b and c 
E) b and d

Quizplus · Accepted Answer

Cutting at b and d would result in a crossover. Cutting at a and c would only lead to a heteroduplex (no crossover). The other combinations are not normally chosen.

In the Following Schematic Drawing of a Holliday Junction That