How the Body Works: Independent Assortment

The process of independent assortment of chromosomes during the first division of meiosis ensures that each sperm and ovum contains slightly different information, and that all the progeny produced will have their own individual characteristics. In this diagram, dark brown cards represent maternal chromosomes and light brown cards paternal chromosomes. Cards with the same symbol represent the homologous chromosomes. Using only three sets of cards, one can see that it is possible to arrive at eight different combinations, or assortments, of chromosomes. Human beings have forty-six chromosomes arranged in twenty-three pairs within their cells. Independent assortment of these means that the possible number of sperm with slightly different genetic information exceeds eight million.