Mendel’s work was really not appreciated until advances in cytology enabled scientists to better study cells. In 1900, Hugo deVries (1848–1935) of Holland, Carl Correns (1864–1933) of Germany, and Erich von Tschermak (1871–1962) of Austria examined Mendel’s original 1865 paper and repeated the experiments. In the following years chromosomes were discovered as discrete structures within the nucleus of a cell. In 1917, Thomas Hunt Morgan (1866–1945), a fruit fly geneticist at Columbia University, extended Mendel’s findings to the structure and function of chromosomes. This and subsequent findings in the 1950s were the beginning of the modern era of genetics.