A law of heredity which is the basic law of genetics.
It was advanced by Gregor Johann Mendel, a Catholic priest, Abbot of Brünn, Moravia, as a result of his experiments with the behavior of plants under hybridization.
He experimented particularly with garden peas.
By tracing two opposed characters through a series of progeny, he concluded that the offspring of the peas behave, in regard to the peculiarities of the parent peas, in a well-defined manner which may be reduced to the terms of a "natural law."
For example, the offspring of tall and dwarf varieties of crossed sweet peas were of the tall type to the exclusion of the dwarf, the tall trait being known as dominant; while the self-fertilized seeds of the tall generation produced specimens of each in a definite ratio of 3:1, the temporarily obscured trait, dwarfishness, known as recessive.
The self-fertilized seed of the specimens of those exhibiting dominant characters produced both tall and dwarf, some of which bred pure, others of which produced mixed types.
The generation which exhibited recessive traits, however, bred pure.
Mendel's Law gave a final blow to the theory of natural selection, and has exercised an enormous influence on biology and scientific breeding.
New Catholic Dictionary