, Mendelian inheritance typically refers to traits with distinct alternate forms (like violet or white flowers). In contrast, polygenic traits (such as human height or skin colour) are controlled by three or more genes, show a continuous gradient of variation rather than distinct categories, and are influenced by the environment. Since these traits do not follow the simple single-gene dominance/recessive patterns observed by Mendel, they are considered a form of Non-Mendelian inheritance .