What occurs at the end of telophase?

At the end of telophase, the key event is the reformation of the nuclear membrane and the nucleolus around each set of chromosomes at opposite poles of the cell. This process signifies the conclusion of nuclear division, as the chromosomes, which have been separated during earlier stages of mitosis, begin to de-condense, returning to their less tightly coiled state which is typical for interphase. The reformation of these structures is crucial for restoring the cell's nucleus, allowing it to perform its regular functions and prepare for the next round of cell division.

This strengthening of the nuclear envelope helps ensure that the genetic material is properly enclosed within the nucleus, providing a stable environment for DNA during the interphase stage. Thus, the reformation of the nuclear membrane and nucleolus is a definitive marker of telophase, highlighting its role in ensuring that both daughter cells will have their own complete set of genetic material once division is complete.