TaxOnTree: a tool that generates trees annotated with taxonomic information

Phylogenetic analysis is a widely used approach for analyzing and illustrating gene/protein/species evolution and is being benefited by the increasing number of species with their DNA/genome sequenced. Generating a phylogenetic tree with sequences from hundreds of species can be considered a routine task. However, tree visualization has been challenged to organize and bring by accessible means relevant information, e.g. taxonomy, about the sampled genes/proteins. Here we present TaxOnTree, a computational tool that incorporates and allows a quick accession of the taxonomic information of samples in a phylogenetic tree. TaxOnTree takes as input a single phylogenetic tree in Newick format containing gene/protein identifiers from NCBI or Uniprot databases in their leaves but TaxOnTree also allows users to have as input a protein identifier, a single protein in FASTA, a list of protein accessions, or a(n) (un)aligned multi-FASTA file. Non-tree inputs are submitted to a phylogenetic reconstruction pipeline implemented into TaxOnTree. The tree provided by the user or generated by the pipeline is converted to Nexus format and then automatically annotated with the taxonomic information of each sample comprising the tree. The taxonomic information is retrieved by web requests from NCBI or Uniprot servers or from a local MySQL database and annotated as tags in the tree nodes. The final tree archive is in Nexus format and should be opened with FigTree software which allows visual inspection, by branch coloring or tip/node labeling, of the taxonomic information incorporated in the tree. TaxOnTree provides prompt inspection of the taxonomic distribution of orthologs and paralogs. It can be used for manual curation of taxonomic/phylogenetic scenarios and coupled to any tool that links homologous sequences to a seed sequence. TaxOnTree provides computational support to help users to inspect phylogenetic trees with a taxonomic view, even without being taxonomy experts. TaxOnTree is available at http://bioinfo.icb.ufmg.br/taxontree.