1. The science that describes inheritance of in-born characteristics is genetics. The term "genetics" was coined around the turn of the century, but much of the basic theory of genetics derives from the work of a monk who lived in Bohemia in the middle of the 19th century. The monk's name was Gregor Mendel
2. Mendel used the common garden pea for his experiments in heredity. Studying a small number of easily observed traits (phenotypes), Mendel was able to deduce the existence of factors in cells that controlled their propagation from one generation to the next (we now call them genes).
3. Mendel hypothesized that each organism receives one gene from each parent. He showed that these genes can impose their phenotype on the organism (dominant) or the phenotype may not be seen, become cryptic (recessive) though it can be revealed as still present by its phentoype reappearing in subsequent generations.
4. By mating peas with distinct phenotypes specified by alternative states of genes he was able to demonstrate that the ratio of phenotypes produced in successive generations can be easily predicted.

Pages in this unit:

1. Some genetic nomenclature; Mendel's experiments with peas
2. Patterns of inheritance of traits in Mendel's experiments