I have a question about the occurence of meiosis.
I was told meiosis occurs during gametogenesis (formation of gametes such as sperm/ova). And during meiosis 1 - prophase 1 there is crossing over occuring to create more diversity. My question is crossing over of whose chromosomes because we have 2 pairs of every chomorome (not chromatid)??? Each individual has its own set of chromosomes, I can't see how crossing over can occur during the formation of 4 sperm or 1 egg because fertilization has not occured yet. And does meiosis occur during fertilization, if yes the result would be 4 genetically distinct cells in one human being??? If no, then how can there be a genetically distinct zygote in result that has traits from both father and mother. I am not sure if the chromosomes are just mixed during fertilization (when sperm fertilizes the egg).
I'm just confused, please clear that up for me. (ultimately i'm asking where meiosis occurs)
Thanks in advance.