In order to do this, a lethal stock of Drosophila melanogaster is used, containing flies that are heterozygous for four mutated traits; curly wings (Cy), plum colored eyes (Pm), dichaete wings (D), and short stubble bristles on the abdomen (Sb). The mutated Cy and Pm genes are on the second chromosome, whereas the D and Sb genes are on the third chromosome. With this knowledge, and the application of Mendel's Principle of Independent Assortment, it can be assumed that the specific characteristics will arrange independently. By examining the progeny, one is able to detect where the chromosomal mutation occurs (Mapping of unknown Mutants in Drosophila, Bumbulis.) .
Another useful technique for the classification of mutants is through the biochemical separation of D. melanogaster's eye pigment. A mutation in any vital pigment produces eyes different than that of the wild-type fly, which possesses brick-red eyes. This natural color is the result of a mix of brown pigments known as ommochromes, and red pigments, or pteridines (Biochemical Separation of Eye Pigments, Bumbulis.) Mutant eye colors, which can range anywhere from another shade of red, to brown, apricot, or white, as mentioned before, are the result of any defect in a gene coding for that pigment. By obtaining pigment from flies of the unknown stock and transferring them onto treated paper, the pigments can be separated through the process of paper chromatography. Upon viewing the finished product in Ultraviolet light, unique banding patterns corresponding to the migration of each specific eye pigment can be seen. By comparing known pigments to those of the unknown stock, similarities can be drawn from common banding patterns. Furthermore, reference front (Rf) values can be calculated by dividing the distance of the substance by the distance of the solvent run (Separation of Drosophila Eye Pigments, Bumbulis.) Comparisons can then be made between the known and unknown substances.
