Question

What is the role of crossover sites?

Answer 1

1. The role of crossover sites is a significant regulatory event as it regulates the number of chiasmata holding the homologs together at the end of the prophase.

2. The number of crossovers is controlled to achieve two outcomes.

3. First, it is essential that every homolog pair is connected by at least one chiasma, to ensure that homolog bi-orientation can be achieved in meiosis I.

4. Second, in most organisms crossovers are limited in number and well-spaced along with the homologs by a phenomenon called crossover interference, where crossovers tend to suppress the formation of other crossovers in their vicinity.