Mendeusm

   , MENDEL'S LAW

   Mendel's law of heredity, called Mendelism, was expounded by an Austrian monk in the mid-nineteenth century. Gregor Johann Mendel (1822-1884) was born of peasant stock in the part of the Austro-Hungarian Empire that later became Czechoslovakia. Though he was extremely poor and had a meager education, he was able to attend the University of Vienna through the help of a friendly patron. Mendel became a substitute teacher at the Brunn Modern School, a title he retained during his fourteen-year tenure. But from the very beginning he worked unceasingly on his theory of the laws of heredity. Mendel's experiments with peas had shown, that the characteristics of the parents of cross-bred offspring reappear in certain proportions in successive generations according to definite laws. He propounded three laws: the law of segregation; the principle of independent assortment; and the principle of dominance.

   About 1900, three men independently did similar experiments and derived the same conclusions: Hugo de Vries of the Netherlands; Carl Correns of Germany; and Erich von Tschermak of Austria. But Mendel had anticipated them by thirty-five years. Since then Mendelian genetics has become a new science, and it has formed the bridge between the other two great generalizations of nineteenthcentury biology—cell theory and the theory of evolution. Mendel's only recognition during his lifetime came in the monastery, and that was his election as abbot at Brunn.