Why doesn't crossing over happen in mitosis?

Question

If there was crossing over in mitosis, then there would various nature of somatic cells. May be that's the logic, but what is the mechanism? Why are there no crossover events during mitosis?

Answer 1

Crossing over happens in Prophase I of meiosis only. The nature of meiosis is to create variation in gametes or sex cells so that offspring look different. This is why you and your sibling do not look the same (with the exception of twins, which is another post entirely). The purpose of mitosis is to heal/repair and grow organisms from a zygote (a fertilized egg) into adult. If crossing over occurred in mitosis every time we were hurt as an adult that somatic cell (any cell that is not a gamete) would be repaired and look and function differently than the previous cells.