Many genes found in Drosophila have equivalents in higher organisms, hence study of the Drosophila genome can relay information regarding human genes. Most of the genes that encode spatial pattern of cell types and body parts have now been identified, such as those involved with hedgehog signalling.
The Drosophila genome is ~165 Mb and contains 13,000 genes. This fruit fly has four pairs of chromosomes: the X/Y sex chromosomes and the autosomes 2, 3 and 4. Chromosome 4 is relatively small.
Embryonic Cell Fate:
During animal embryonic development, localized Hh signals organise patterns and cell types by controlling cell fates. In Drosophila, embryonic segments and nascent imaginal discs are divided into anterior (A) and posterior (P) compartment cells. A cells transcribe Ci, a transcription factor and P cells transcribe engrailed (en), a homeobox containing transcription factor.A Hh signal from P cells, allows transcription of wg signalling molecules in embryonic development and dpp in leg and wing imaginal discs.
When A cells receive a Hh signal, Ci directly activates Hh target gene transcription. This is thought to be allowed by an increase in Fu activity and decrease in Cos2 activity.
