In this month’s issue of Genome Biology, Igor V. Grigoriev, Adam Kuspa and colleagues present the genome of Dictyostelium purpureum, a close relative (by around 400 million years) of Dictyostelium discoideum, the model Dictyostelid.
Until relatively recently, these interesting organisms were commonly known as slime molds; however they have now been classified as bona fide Amoebozoa. Dictyostelids are studied primarily to understand the evolution of multicellularity, because they exist in both single-celled and multicellular states. When nutrients are lacking, single celled organisms group together, forming multicellular ‘fruiting bodies’ with terminally differentiated spores. How this process works is still under investigation.
Kuspa and colleagues have sequenced the genome of D. purpureum and compared it to that of D. discoideum. They found that genes involved in forming the multicellular stage have evolved much faster than others in the genome. The authors propose that this may be due to either relaxed selection or accelerated evolution due to social conflict, which occurs when some individuals within the population have greater resources (or ability to use those resources) and exploit those with less.
This sequence provides a fantastic resource for Dictyostelid biologists, aiding the continuing research into the evolution of multicellularity and the unusual biology of these fascinating and ubiquitous organisms.
Kuspa and colleagues provide the genome sequence both in GenBank and at dictybase.org