Pleiotropy correlations and responses to selection most often exemplify pleiotropy. Pleiotropic traits had been previously recognized in the scientific community but had not been experimented on until Gregor Mendel's 1866 pea plant experiment. Mendel recognized that certain pea plant traits (seed coat color, flower color, and axial spots) seemed to be inherited together; however, their correlation to a single gene has never been proven. The term "pleiotropie" was first coined by Ludwig Plate in his Festschrift, which was published in 1910. He originally defined pleiotropy as occurring when "several characteristics are dependent upon ... [inheritance]; these characteristics will then always appear
Plant genetics put forth by Mendel. W.E. Castle discovered that while individual traits may segregate and change over time with selection, that when selection is stopped and environmental effects are taken into account, the genetic ratio stops changing and reach a sort of stasis, the foundation of Population Genetics. This was independently discovered by G.H. Hardy and W. Weinberg, which ultimately gave rise to the concept of Hardy-Weinberg equilibrium published in 1908. For a more thorough exploration of the history of population genetics, see History of Population Genetics by Bob Allard. Around this same time, genetic and plant breeding experiments in maize