FIGURE 2 The gametes at the top left represent a corn plant with colored, starchy seeds that is heterozygous for these seed-color and seed-texture genes (CcWxwx). One chromosome 9 in the diploid has abnormal extremities. This plant was crossed with a corn plant (top right) having colorless, starchy seeds (ccWxwx). Genetic crossing over in the colored, starchy plant produced colorless, waxy progeny of genotype ccwxwx. Microscopic examination confirmed that genetic crossing over involves physical recombination of chromosomes: one end of the abnormal chromosome 9 was replaced with a normal end, containing the colorless-seed gene.