On Tuesday night, when I posted my personal picks from this week's crop of articles published in PLoS ONE, I omitted (due to a technical glitch on the site), to point out that a blog-friend of mine John Logsdon published his first PLoS ONE paper on that day:
It's a updated and detailed report on the ongoing work in my lab to generate and curate an "inventory" of genes involved in meiosis that are present across major eukaryotic lineages. This paper focuses on the protist, Trichomonas vaginalis, an organism not known to have a sexual phase in its life cycle.
Here is the paper (and check John's post for his experiences publishing in PLoS ONE):
Meiosis is a defining feature of eukaryotes but its phylogenetic distribution has not been broadly determined, especially among eukaryotic microorganisms (i.e. protists)--which represent the majority of eukaryotic 'supergroups'. We surveyed genomes of animals, fungi, plants and protists for meiotic genes, focusing on the evolutionarily divergent parasitic protist Trichomonas vaginalis. We identified homologs of 29 components of the meiotic recombination machinery, as well as the synaptonemal and meiotic sister chromatid cohesion complexes. T. vaginalis has orthologs of 27 of 29 meiotic genes, including eight of nine genes that encode meiosis-specific proteins in model organisms. Although meiosis has not been observed in T. vaginalis, our findings suggest it is either currently sexual or a recent asexual, consistent with observed, albeit unusual, sexual cycles in their distant parabasalid relatives, the hypermastigotes. T. vaginalis may use meiotic gene homologs to mediate homologous recombination and genetic exchange. Overall, this expanded inventory of meiotic genes forms a useful "meiosis detection toolkit". Our analyses indicate that these meiotic genes arose, or were already present, early in eukaryotic evolution; thus, the eukaryotic cenancestor contained most or all components of this set and was likely capable of performing meiotic recombination using near-universal meiotic machinery.