One of the most exciting developments in contemporary cell biology is the discovery of molecular mechanisms that control the progression of eukaryotic cells through the cell cycles (mitotic and meiotic).

It is now well established that there is a conserved set of protein kinesis in all eukaryotic cells which is involved in the process of triggering major cell cycle transitions.

There is in-built genetic mechanisms that prevent entry into next phase of the cell cycle until the events of the earlier phase is completed.

Scientists have discovered signal systems that regulate progression through specific control points in the division cycles. There are also checkpoints and feedback controls to coordinate events during the progress of cell cycle. For example, once DNA replication is over, initiation of a new S phase is prevented until the cell completes mitosis.

ADVERTISEMENTS:

There are some drugs e.g. colchicines, which prevents the formation of spindle fibers and thereby not allowing the chromosomes to move to opposite poles.

This results in a cell with double the number of chromosomes. Hence, the drug finds application is inducing polyploidy (cells with multiple chromosome number).