Mendelian inheritance

Gregor Mendel published his results from his experiments on simultaneous inheritance of pea plant phenotypes in 1866. He examined 556 plants and classified them according to their form (wrinkled or round) and color (green or yellow). According to Mendel's theory, these phenotypes should appear in the ratio 9:3:3:1, since the two phenotypes are believed to be independent and because both phenotypes show dominance—yellow is dominant over green and round is dominant over wrinkled.