- crossing over - homologous chromosome pair along their length gene by gene. - Breaks occur along the chromosomes and they rejoin trading some of their genes
NB crossing over occurs in prophase I
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- Independent assortment - chromosomes randomly move to separate poles during meiosis I. - Each gamete will have different combination of chromosomes and contain a mixture from both father and mother
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- Segregation of sister chromatids in Anaphase - often one chromatid is a mixture of paternal and maternal DNA while other chromatid is not
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- Random fertilization - each gamete contains a different set of DNA. - any male gamete will fuse with any female gamete so each offspring will be genetically different which cause variation
