"The birth of modern genetics was due to the discoveries of Gregor Mendel (1823–1884), an Augustinian monk who taught natural science to high school students in the town of Brno in Moravia (now part of the Czech Republic). Mendel’s greatest insight was to focus on discrete, clear-cut characters rather than measuring continuously variable properties, such as height or weight. Mendel used pea plants and studied characteristics such as whether the seeds were smooth or wrinkled, whether the flowers were red or white, and whether the pods were yellow or green, etc. When asked if any particular individual inherited these characteristics from its parents, Mendel could respond with a simple “yes” or “no,” rather than “maybe” or “partly.” Such clear-cut, discrete characteristics are known as Mendelian characters(Fig. 1.01)."