Genetics Genetics Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms. Gregor Mendel, a scientist and Augustinian friar, discovered genetics in the late 19th-century. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but
Johann Karl Nestler stock animals and their offspring Nestler hoped to explain the (genetic history). Examination of the records of the ancestors of the best breeding animals, called by Nestler "developmental history" () was for him the reverse side of the same coin. According to Wood and Orel the search for rules of heredity in sheep created an atmosphere of enquiry about heredity in general, which had influence on later work of Gregor Johann Mendel, himself a student at the Faculty of Philosophy in 1840–43. Nestler was also a very active member of the "Moravian-Silesian Society for Advancement of Agriculture" (, in which