Meiosis and the origin of gamete variation

BiologyCell BiologyAges 15–16

Step through each phase of meiosis I and II in a cell with n pairs of homologous chromosomes. Toggle crossing over and watch the number of possible gamete types change: independent assortment alone already gives 2ⁿ types, and adding crossing over sends the number of combinations soaring — this is exactly why offspring differ from their parents.