A little about Drosophila and genetics

About Drosophila melanogaster
Drosophila melanogaster is a species of fruit flies, with a length of about 2.5 mm, red eyes and a yellow-brown colored body with black stripes. Distiction of the sexes is easiest to do by looking at the abdomen, which is pointed in females, whereas males have a more blunt abdomen with a thick black area at the end.

D. melanogaster is one of the most widely used model organisms in genetic research. This is mainly due to its being very easy to breed in a laboratory and its short generation time (around 2 weeks under good conditions). It also has only four pairs of chromosomes. Fruit flies were first used in genetic research over 100 years ago by scientists Charles W. Woodworth and W. E. Castle. In the early 20th century Thomas Hunt Morgan conducted several important genetic studies using Drosophila. Morgan's student Alfred Sturtevant continued the reasearch and presented the first chromosomal maps of Drosophila. The 1995 Nobel Prize in medicine was awarded to Edward B. Lewis, Christiane Nüsslein-Volhard and Eric F. Wieschaus for work conducted on Drosophila.

Over the years, Drosophila has gained enormously in popularity among biologists. Today, thousands of scientists work with it with the focus switching more and more towards developmental biology and the embryonic development in Drosophila.

Approximately 50% of fruit fly protein sequences have mammalian analogues and Drosophila is used as a model in research on such human diseases Parkinson's and Huntington's.

The Drosophila genome
Drosophila melanogaster has four pairs of chromosomes: one X/Y pair and three autosomes which are usually referred to simply as 2, 3 and 4. The genome consists of around 165 million bases and about 14,000 genes. The entire genome has recently been completely sequenced. The somewhat unstructured way in which Drosophila genes are named is slightly infamous among geneticists. The names of genes are often taken from the phenotype caused by a mutation in the gene, which can be a little confusing. Among the more humorous examples one finds such genes as "cheap date", which in its mutated form causes an increased sensitivity to alcohol intoxication. The names of the genes exist both as a full description and as an abbreviation - for instance, the gene "purple eyes" (which causes purple eyes when subject to a mutation) is most often referred to as "pr". A capital letter in the beginning of the abbreviation means the mutated version is dominant.

It is important to note that recombination only occurs in females in Drosophila.

Mutations in DrosophiLab
DrosophiLab lets you create fruit flies with complete control over the genome, using the supplied Chromosome Editor. You can alter, for instance, wing shape, body color, eye shape, antennae, etc. (a total of 20 different genes are currently supported). A complete reference of the mutations supported by the program, where their respective genes are located and what phenotype they lead to, is found in the chromosome map accessed throught the Tools menu of DrosophiLab.



Links: More about Drosophila
An excellent collection of links to Drosophila resources can be found at The WWW Virtual Library. Tons of links ranging from introductory to very advanced level.