genetic variation from meiosis

• what are the three sources of genetic variation arising from meiosis


  crossing over , independent assortment and the random fusion of haploid cells
• When does crossing over occur?


  prophase I of meiosis
• what happens during crossing over during prophase 1


  the chromosomes condense and homologous pairs form a bivalent
• what is synapsis


  the fusion of chromosome pairs at the start of meiosis.
• what is a bivalent


  a pair of homologous chromosomes
• where do the chromatids join to form a bivalent


  at chiasmata
• what are chiasmata


  sites of crossing over
• what is crossing over


  exchange of genetic material between homologous chromosomes
• When does independent assortment occur?


  Metaphase I and II of meiosis
• what happens during independent assortmetn

  the chromosomes distribute themselves randomly at the equator of the spindle
• how do you find out the maximum amount of combinations that chromosomes could be in


  2 to the power of the number of chromosomes
• what is formed when haploid gametes fuse


  a zygote
• what are haploid gametes


  sperm and egg
• What are haploid cells?


  cells with a single set of chromosomes