Classical genetics genetics is often referred to as the oldest form of genetics, and began with Gregor Mendel's experiments that formulated and defined a fundamental biological concept known as Mendelian Inheritance. Mendelian Inheritance is the process in which genes and traits are passed from a set of parents to their offspring. These inherited traits are passed down mechanistically with one gene from one parent and the second gene from another parent in sexually reproducing organisms. This creates the pair of genes in diploid organisms. Gregor Mendel started his experimentation and study of inheritance with phenotypes of garden peas and continued the experiments
Plant genetics 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. Much of Mendel's work with plants still forms the basis for modern plant genetics. Plants, like all known organisms, use DNA to pass on their traits. Animal genetics often focuses on parentage and lineage, but this can sometimes be difficult in plant genetics due to the fact that plants can, unlike most animals, can self-fertilize. Speciation can be easier in many plants due to unique genetic abilities, such as being well adapted to polyploidy.