Gregor Mendel (1822-1884)
Mendel was an Augustinian monk born in Austria who experimented with pea plants and discovered the laws of inheritance. Without even knowing the existence of genes, Mendel found that it was possible that some recessive traits could reappear in future generations. We know that he wrote once to Darwin to share his discovery, but Darwin received the letter, put it in a drawer and never read it. That letter was found after Darwin’s death. One cannot avoid wondering what Darwin would have thought about someone experimentally proving what he supposed to happen in theory. Mendel found that traits came in pairs, were inherited from father and mother, and could be either dominant or recessive.
What Mendel discovered is that if we breed together a population of yellow and green peas, where the yellow color is a dominant trait (AA), and the green color is recessive (aa), the offspring in the first generation will only be yellow peas (Aa). The second generation will get all possible combinations of the trait (AA, Aa, aA and aa). The result will be a ratio 1:3. Green peas will reappear. It was until the 20th century when genes were discovered that the genius of Mendel’s work received the credit he deserved.