Mendel Museum of Genetics, Brno, Czech Republic
Ten Years of Observing Peas
In 1865, an Austrian monk living in Brno in what is now the Czech Republic wrote and then published a paper that is now recognized as the foundation of modern genetics. In his paper, Experiments in Plant Hybridization, Gregor Mendel summarized the result of over a decade of experimentation with 30,000 Pisum sativum plants (otherwise known as the humble garden pea).
Mendel described how seven key traits were passed from generation to generation of plants. He carefully observed seed shape and color, flower color, pod shape and color, and size and shape of the plant’s stem.
Through careful experimentation of cross-breeding different strains of peas, he discovered that some traits appeared to be dominant and others were recessive. He posited that each pea plant contained two copies of each trait, and that certain forms of an individual trait could overpower (or dominate) others. He showed that violet-colored flowers dominated white-colored flowers, for example, and went on to identify the dominant forms of each of the seven traits studied. Only if both copies of the trait were the recessive version would that version actually be expressed (resulting in, ...