The most significant breakthrough in genetics was made by the Austrian monk Gregor Mendel(1822-84). He observed specific features of the pea plant and counted the number of individuals in which each characteristic appeared through several generations. By concentrating on just a few features and determining what proportion of each generation received them, he was able to demonstrate specific patterns of inheritance. The discrete nature and independent segregation of genetic characteristics that he observed became known as Mendel`s laws of inheritance.
Genes, the Genome and Mutation
Mendel discovered that characteristics are passed from generation to generation in the form of discrete units. Once the structure of the DNA was established, these units called genes, could be understood at a molecular level.