Gregor Mendel’s scientific work (1822-1884) and the publication of his discoveries (Experiments in Plant Hybridisation - 1865) mark the beginning of genetics (the study of heredity and genes). Using his now famous scientific approach, integrating a statistical tool, Mendel studied the transmission of traits in vegetable plants. He chose the pea (pisum sativum) that satisfied all of his requirements. To understand the transmission of one characteristic from one generation to another, he artificially pollinated two varieties of peas from pure lineages. One with the "smooth seed" characteristic, the other with the "wrinkled seed" characteristic. The descendant (F1) only possessed smooth seeds.
He followed the experiment carrying out the autopollination of generation F1. What a surprise to see a constant proportion of the "wrinkled seed" characteristic in the F2 descendant.
From this experiment using millions of seeds, Mendel was able to confirm that:
The word "factor" used above has been replaced by the word "gene" that was not discovered until the beginning of the XXth century. Note that his publication did not have the expected impact during that time and he had to wait almost a half-century for it to be rediscovered.
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