Question

In which phase does the cohesin linkage between sister chromatids get established?

Answer 1

Cohesin linkage:

1. The cohesin linkage is established between sister chromatids during the S phase and it seems to be closely tied to DNA replication.
2. Cohesin complexes associate with the chromosome before replication starts, but passage through the S phase is required to transform these complexes into the cohesive structures that link the duplicated sister chromatids until metaphase.
3. If cells of yeast are engineered for cohesin to not be expressed till the S phase occurs, the sister-chromatid cohesion does not take place.
4. This shows that cohesion can be established only if the cohesin complex is found during the S phase.