The Father of Genetics

“Pea hybrids form germinal and pollen cells that in their composition correspond in equal numbers to all the constant forms resulting from the combination of traits united through fertilization.”
      Gregor Johann Mendel was born on July 22, 1822 to peasant parents in a small agrarian town in Czechoslovakia. During his childhood he worked as a gardener, and as a young man attended the Olmutz Philosophical Institute. In 1843 he entered an Augustinian monastery in Brunn, Czechoslovakia. Soon afterward, his natural interest in science and specifically hereditary science led him to start experiments with the pea plant.  Mendel's attraction for scientific research was based on his love of nature in general. He was not only interested in plants, but also in meteorology and theories of evolution. However, it is his work with the pea plant that changed the world of science forever.
      His beautifully designed experiments with pea plants were the first to focus on the numerical relationships among traits appearing in the progeny of hybrids.  His interpretation for this phenomenon was that material and unchanging hereditary “elements” undergo segregation and independent assortment.  These elements are then passed on unchanged (except in arrangement) to offspring thus yielding a very large, but finite number of possible variations.
     Mendel often wondered how plants obtained atypical characteristics. On one of his frequent walks around the monastery, he found an atypical variety of an ornamental plant. He took it and planted it next to the typical variety. He grew their progeny side by side to see if there would be any approximation of the traits passed on to the next generation. This experiment was “designed to support or to illustrate Lamarck's views concerning the influence of environment upon plants.”  He found that the plants' respective offspring retained the essential traits of the parents, and therefore were not influenced by the environment. This simple test gave birth to the idea of heredity.
Overshadowing the creative brilliance of Mendel's work is the fact that it was virtually ignored for 34 years. Only after the dramatic rediscovery of Mendel’s work in 1900 (16 years after Mendel's death) was he rightfully recognized as the founder of genetics.1
Why Peas?
     Mendel was well aware that there were certain preconditions that had to be carefully established before commencing investigations into the inheritance of characteristics. The parental plants must be known to possess constant and differentiating characteristics.  To establish this condition, Mendel took an entire year to test “true breeding” (non-hybrid) family lines, each having constant characteristics.   The experimental plants also needed to produce flowers that would be easy to protect against foreign pollen.  The special shape of the flower of the Leguminosae family, with their enclosed styles, drew his attention.  On trying several from this family, he finally selected the garden pea plant (Pisum sativum) as being most ideal for his needs.  Mendel also picked the common garden pea plant because it can be grown in large numbers and its reproduction can be manipulated.  As with many other flowering plants, pea plants have both male and female reproductive organs.  As a result, they can either self-pollinate themselves or cross-pollinate with other plants. In his experiments, Mendel was able to selectively cross-pollinate purebred plants with particular traits and observe the outcome over many generations.  This was the basis for his conclusions about the nature of genetic inheritance.