crossing over

• explain why genetic variation produced in meiosis 2 is dependent on crossing over

  • crossing over enables exchange of genetic information between non sister chromatids
  • Non sister chromatids assort, independently
• chiasmata

  point where chromatids cross
• steps

  1. non sister chromatids cross over
  2. they tangle
  3. tension breaks off part of chromatid
• new combo of alleles in gametes increase genetic variation
• allele

  variant form of a gene
• chromosomes break + rejoin to make new combo of alleles in gametes