Forward genetics a bare minimum for the appearance of specific phenotypes. However, such initial screens were either incomplete as they were missing redundant loci and epigenetic effects, and such screens were difficult to undertake for certain phenotypes that lack directly measurable phenotypes. Additionally a classical genetics approach takes significantly longer. Gregor Mendel experimented with pea plant phenotypes and published his conclusions about genes and inheritance in 1865. Around the early 1900s Thomas Hunt Morgan was mutating Drosophila using radium and attempting to find heritable mutations Alfred Sturtevant later began mapping genes of Drosophila with mutations they had been following. In the 1990s
Classical genetics as molecular genetics. At the base of classical genetics is the concept of a gene, the hereditary factor tied to a particular simple feature (or character). The set of genes for one or more characters possessed by an individual is the genotype. A diploid individual often has two alleles for the determination of a character. Classical genetics is the part of genetics that is solely about the method in which genetic traits are transmitted via the acts of reproduction. Genetics is, generally, the study of genes, genetic variation, and heredity. The process by which characteristics are passed down from parents