Gregor Mendel
GREGOR MENDEL (1822–1884) was a monk and a physicist. Some of his fellow monks were crop breeders, and he began investigating heredity to help them to improve their crops. Being a physicist, he looked for simple laws that could be expressed mathematically, and this happened to be a good way of approaching heredity. By an inspired guess, Mendel chose to study “either/or” characteristics, such as seed color in peas. Others scientists were looking at characteristics that appear to blend in the offspring, such as size. Though these are more common, they are far more difficult to study. Mendel’s results, published in 1865, were not understood until 1900, when scientists made the same discoveries again. “Mendelism” was born, and in 1909 the word “gene” was coined for his hereditary particles (p. 52). At first Mendelism seemed to oppose Darwinism, because “either/or” characteristics would not create the small variations on which natural selection could work. In the 1920s it was realized that most characteristics are governed by dozens of genes, each with small effects that can add up to a large effect. The many genes controlling a characteristic such as size can provide small variations, but each gene behaves in exactly the same way as a gene for an “either/or” characteristic. The ideas of Mendelism clearly supported Darwin, and they were combined in a new theory—neo-Darwinism.
Finding genes
Mendel worked with plant varieties (different types within a species). He crossed varieties that had distinct, contrasting characteristics, such as seed color. His results showed that heredity was not blending, but involved discrete units, now called genes.
Blue beads -
Normal fly - Tiny mutant fruit fly -
Source Citation
Gale Document Number: GALE|CX1907200029