Botanist, Scientist (1822–1884)
Gregor Johann Mendel
A number of hypotheses were suggested to explain heredity, but Gregor Mendel , a little known Central European monk, was the only one who got it more or less right. His ideas had been published in 1866 but largely went unrecognized until 1900, which was long after his death. His early adult life was spent in relative obscurity doing basic genetics research and teaching high school mathematics, physics, and Greek in Brno (now in the Czech Republic). In his later years, he became the abbot of his monastery and put aside his scientific work.
Common edible peas
While Mendel's research was with plants, the basic underlying principles of heredity that he discovered also apply to people and other animals because the mechanisms of heredity are essentially the same for all complex life forms.
Mendel formulated the law of segregation as a result of performing monohybrid cross experiments on plants. The specific traits that were being studied exhibited complete dominance. In complete dominance, one phenotype is dominant and the other is recessive. Not all types of genetic inheritance however exhibit complete dominance.
In incomplete dominance, neither allele is completely dominant over the other. In this type of intermediate inheritance, the resulting offspring exhibit a phenotype that is a mixture of both parent phenotypes.
Law of Segregation
Mendel performed dihybrid crosses in plants that were true-breeding for two traits. For example, a plant that had green pod color and yellow seed color was cross-pollinated with a plant that had yellow pod color and green seeds. In this cross, the traits for green pod color (GG) and yellow seed color (YY) are dominant. Yellow pod color (gg) and green seed color (yy) are recessive. The resulting offspring