Doubling of the chromosomes occurs in the Interphase stage of mitosis. After the cell replicates its DNA, the cell then enters the PROPHASE stage of mitosis. This stage is described as the true starting point of cell division in mitosis (as well as meiosis). Several events occur in the Prophase stage of mitosis, these includes:
- the movement of centrioles (a collection of microtubules) to the opposite side of the cell
- chromatin condensation
- disappearance and/or breakdown of nucleolus
- formation of spindle fibers
