Heredity
IF TWO DIFFERENT-COLORED PAONTS are mixed, they blend and original colors cannot be separated. When two organisms breed sexual reproduction, some characteristics do seem to blend, but others often vanish, only to reappear in later generations. To the Austrian monk Gregor Johann Mendel (1822-1884), this suggested that heredity - the link between generations - must obey some system of rules. In the monastery gardens, Mendel carried out experiments on the common garden pea. By carefully controlling which plant bred with which, he recorded how characteristics as flower color were passed on. Mendel concluded that inherited characteristics do not blend, but remain separate. Each characteristics is determined by two factors, or "elements" , one from each of each pair of factors, one of often "dominant" , meaning that it masks the other. However, the masked or "recessive" factor does disappear, and it may become unmasked in later generations Although Mendel's work was published in 1865. it was not until 20th century that its true importance was finally appreciated.