Mendel’s Pea Cross Ratios

Mendel’s pea plant crosses show how traits can disappear in one generation and return in the next. When he crossed plants, one parental trait sometimes seemed to vanish in the F1 generation and reappear in the F2 generation. Mendel used this pattern to explain why some traits are dominant and others are recessive.

When Gregor Mendel performed monohybrid crosses of pea plants differing by single traits, such as pod color, he only saw one parental phenotype disappear in the first filial, or F-one, generation. And then, reappear in the second filial, or F-two generation, meaning that one phenotype was dominant over the other. The offspring with the dominant ...