Punnett squares illustrating Mendel's laws of segregation and independent assortment. These Punnett squares show the genotypes of gametes produced by each heterozygous parent during meiosis (on the sides of the squares) and the genotypes and phenotypes of the offspring that result from the various unions of gametes (in the center of the squares). a, b) According to Mendel's law of segregation, the 2 alleles of a gene are segregated to different gametes during meiosis and then united at random, 1 from each parent, at fertilization. b) According to Mendel's law of independent assortment, when 2 genes are on different chromosomes (i.e. unlinked), they segregate independently. Only offspring phenotypes are shown. In these examples, T is the dominant allele that causes pea plants to be tall and G is the dominant allele that causes pea pods to be green.