Genetic variation

• Independant assortment

  • During metaphase 1 the homologous pairs of chromosomes line up opposite each other on either side of the equator.
  • It is random on which side of the equator the paternal and maternal chromosome of each pair aligns.
• Crossing over

  • During prophase 1 the homologous chromosomes pair to form bivalents.
  • Crossing over genetic material can occur between the non-sister chromatids of bivalents.
  • Breaks can occur in the genetic material where the chromatids cross over and parts of the chromatids are exchanged between the homologous pairs.
  • Resulting in new combinations of alleles in the resulting gamete.