Drosophila Hydei A molecular evolutionary phylogenetic study

1. Drosophila HydeiA molecular evolutionary phylogenetic study AurashKamalipour Biochemistry – Undergraduate October 21, 2009 Dan Graur Ex scientiafiducia in toto

2. Drosophila, Do the dew. • The name “Drosophila” comes from Latin, meaning “dew lover.” • Drosophila is everywhere: deserts, alpine zones, tropical climates, swamps, and urban areas… just to name a few. • Drosophila larvae eat yeast which grows in fermenting fruit… as such Drosophila (aka vinegar flies) are attracted to signs of fermentation… e.g. vinegar formation. • The genus’s phylogenetic relationships are very poorly understood… Currently the Drosophila genus is paraphyletic… there are around 1500 KNOWN species of Drosophila (out of possibly +5000)… and it has many multifurcated points. Ergo, the phyllogram IMHO is JUNK. Drosophila hydei

3. Too normal to live, too common to dieDrosophila’s diversity destroys discernment of defining distinctions. In other words, the Drosophila genus (which encompasses the Sophophora subgenus, et al.) is devoid of any one special defining characteristic which could help define the phylogenetic relationships of the subgroups/species in one subgenus between any of the subgroups/species in another subgenus. Drosophila traits are all “mixed” between all species, regardless of subgenus assortment. This means that we cannot rely on phenotype based characterization as a measure of evolutionary relationship… but we knew that already, didn’t we? Currently the evolutionary relationships between these different flies are being elucidated through a concerted composition of data and molecular evolutionary techniques. A Drosophila genome sequencing project is underway… the nuclear and mitochondrial genes of the different flies are analyzed (using ME techniques1) to provide us with more telling insights on the true ancestral neighbors in this medley of myia(flies). Theories are abound on what caused the diversity in Drosophila. .. The fact that they are small, ubiquitous, and short-lived means they are subject to stronger evolutionary forces and speciation. 1 Techniques used were NJ and MP phylogeny tree building using homologous genes which have been properly mapped and aligned.

4. What do we care? What is known: Drosophila subgenre are being sequenced and categorized, with hopes that the distinctions between each genus can be accurately defined by evolutionary relationships, and perhaps even relevance. What remains to be known: The breadth of the Drosophila genus remains to be discovered and far exceeds what we’ve already documented (much less sequenced), but in spite of that, we stand to benefit from a better understanding the nature of evolution/speciation. Through studying such rapid-evolving species (with many homologous human disease states) we may eventually be better able to accurately characterize forces, define parameters and algorithmically model the extent through which the natural world acts as modulators to speciation.

5. References: Evolution of genes and genomes on the drosophila phylogeny. Nature , 450 (7167), 2007, 203-218. http://dx.doi.org/10.1038/nature06341Tomas Moran, Antonio Fontdevila, On the phylogeny of the Drosophila hydei subgroup: New insights from combined analyses of nuclear and mitochondrial data, Molecular Phylogenetics and Evolution, Volume 43, Issue 3, June 2007, Pages 1198-1205, ISSN 1055-7903, DOI: 10.1016/j.ympev.2006.12.021. Tomas Moran, Antonio Fontdevila, Phylogeny and molecular evolution of the Drosophila hydei subgroup (Drosophila repleta group) inferred from the Xanthine dehydrogenase gene, Molecular Phylogenetics and Evolution, Volume 36, Issue 3, September 2005, Pages 695-705, ISSN 1055-7903, DOI: 10.1016/j.ympev.2005.04.009. Suppose we could know the nature of speciation as defined by a series of definite, definable parameters which are invariably used in an empirically-supported algorithm of evolution.