The rapid increase in genomic and genome-scale data is resulting in unprecedented levels of discrete sequence data available for phylogenetic analyses. Major analytical impasses exist, however, prior to analyzing these data with existing phylogenetic software. Obstacles include the management of large data sets without standardized naming conventions, identification and filtering of orthologous clusters of proteins or genes, and the assembly of alignments of orthologous sequence data into individual and concatenated super alignments. Here we report the production of an automated pipeline, Hal that produces multiple alignments and trees from genomic data. These alignments can be produced by a choice of four alignment programs and analyzed by a variety of phylogenetic programs. In short, the Hal pipeline connects the programs BLASTP, MCL, user specified alignment programs, GBlocks, ProtTest and user specified phylogenetic programs to produce species trees. The script is available at sourceforge (http://sourceforge.net/projects/bio-hal/). The results from an example analysis of Kingdom Fungi are briefly discussed.
Mitochondria share a common ancestor with the Alphaproteobacteria, but determining their precise origins is challenging due to inherent difficulties in phylogenetically reconstructing ancient evolutionary events. Nonetheless, phylogenetic accuracy improves with more refined tools and expanded taxon sampling. We investigated mitochondrial origins with the benefit of new, deeply branching genome sequences from the ancient and prolific SAR11 clade of Alphaproteobacteria and publicly available alphaproteobacterial and mitochondrial genome sequences. Using the automated phylogenomic pipeline Hal, we systematically studied the effect of taxon sampling and missing data to accommodate small mitochondrial genomes. The evidence supports a common origin of mitochondria and SAR11 as a sister group to the Rickettsiales. The simplest explanation of these data is that mitochondria evolved from a planktonic marine alphaproteobacterial lineage that participated in multiple inter-specific cell colonization events, in some cases yielding parasitic relationships, but in at least one case producing a symbiosis that characterizes modern eukaryotic life.
The fission yeast clade--comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus, and S. japonicus--occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, which suggests a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the budding yeast of Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade.
Hymenoptera is one of the most diverse groups of animals on the planet and have vital importance for ecosystem function as pollinators and parasitoids. Higher-level relationships among Hymenoptera have been notoriously difficult to resolve with both morphological and traditional molecular approaches. Here we examined the utility of expressed sequence tags for resolving relationships among hymenopteran superfamilies. Transcripts were assembled for 6 disparate Hymenopteran taxa with additional sequences added from public databases for a final dataset of 24 genes for 16 taxa and over 10 kb of sequence data. The concatenated dataset recovered a robust and well-supported topology demonstrating the monophyly of Holometabola, Hymenoptera, Apocrita, Aculeata, Ichneumonoidea, and a sister relationship between the two most closely related proctotrupomorphs in the dataset (Cynipoidea + Proctotrupoidea). The data strongly supported a sister relationship between Aculeata and Proctotrupomorpha, contrary to previously proposed hypotheses. Additionally there was strong evidence indicating Ichneumonoidea as sister to Aculeata + Proctotrupomorpha. These relationships were robust to missing data, nucleotide composition biases, low taxonomic sampling, and conflicting signal across gene trees. There was also strong evidence indicating that Chalcidoidea is not contained within Proctotrupomorpha.