Mendel and His Rediscovery.

Gregor Mendel was an Austrian monk who, as a result of experimentation in plant hybridization between 1856 and 1863, discovered that certain parental characteristics are dominant in the next generation and others are what he called recessive (that is, they do not appear but can be passed on to the next generation). Moreover, he found that such parental traits segregate themselves in a precise numerical ratio. Thus, if A represents a dominant round seed shape and a a recessive angular shape, then one-quarter of the progeny will have the dominant (AA), one-quarter the recessive (aa), and one-half will have a dominant and a recessive (Aa or aA), what is now called a heterozygous combi-nation. Mendel's work was scarcely noted at the time. It was not until 1900 that three European biologists, Hugo de Vries, Karl Correns, and Erich von Tschermak independently...