AQA A Level Biology复习笔记4.3.3 Meiosis



  • Meiosis produces daughter cells that are genetically different from each other and to the parent cell
  • This is due to the processes of independent assortment and crossing over
  • Independent assortment
    • The alleles of two (or more) different genes get sorted into gametes independently of one another
    • The allele a gamete received for one gene does not influence the allele received for another gene
    • This is because homologous chromosomes line up in random orientations at the middle of the cell at metaphase as they prepare to separate, meaning that the same parent cell can produce different combinations of chromosomes in the daughter cells


  • Crossing over
    • The process whereby a chromatid breaks during meiosis and rejoins to the chromatid of its homologous chromosome so that its alleles are exchanged



The daughter cells have unique allele combinations - they are genetically different