Prophase

The first stage of mitosis or meiosis ineukaryotic cell division, during which the nuclearenvelope breaks down and strands of chromatinform into chromosomes. Prophase, from the ancient Greek πρό (before) and φάσις (stage), is a stage of mitosis in which the chromatin condenses into double rod-shaped structures called chromosomes in which the chromatin becomes visible. This process, calledchromatin condensation, is involved with thecondensin complex. Since the genetic materialhas been replicated in the prior interphase of thecell cycle, there are two identical copies of each chromosome in the cell.

Those copies are called sister chromatids and they are attached to each other at a DNA element present on every chromosome called the centromere. Also during prophase, giemsa staining can be applied to elicit G-bandingin chromosomes. Crossing over occurs during prophase. Essentially, the chromosomes overlap with one another and exchange genetic information. This allows for genetic recombination.

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