Mendelian inheritance, also called Mendelism, the principles of heredity formulated by Austrian-born botanist, teacher, and Augustinian prelate Gregor Mendel in 1865. These principles compose what is known as the system of particulate inheritance by units, or genes. The later discovery of chromosomes as the carriers of genetic units supported Mendel’s two basic laws, known as the law of segregation and the law of independent assortment.