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
History of model organisms respective work on natural selection and the genetics of heredity. These early works in finding standards to compare organisms against continued into the 20th century as the first model organisms were brought into laboratories. Beginning in the early 1900s "Drosophila" entered the research laboratories and opened up the doors for other model organisms like Tobacco mosaic virus, E. coli, C57BL/6 (lab mice), etc. These organisms have led to many advances in the past century. Some of the first work with what would be considered model organisms started because Gregor Johann Mendel felt that the views of Darwin were insufficient in