MitoTool, a web-based bioinformatics platform, provides a convenient, user-friendly interface for handling human mtDNA sequence data. It contains multiple modules which cover a wide array of functions: (i) to automatically yield a list of the variants in certain mtDNA relative to the revised Cambridge Reference Sequence (rCRS) recommended or the Reconstructed Sapiens Reference Sequence (RSRS) and determine the haplogroup status of that lineage according to Phylotree (www.phylotree.org), (ii) to detect missing sequence variants in certain mtDNA with claimed haplogroup status, (iii) to display the location of the variant, interspecies conservation index and change of amino acid status, (iv) to identify potentially pathogenic mutations based on the reported data, (v) to conduct statistical analysis for haplogroup distribution frequency between case and control groups, and (vi) to retrieve and batch download analytical output and mitochondrion-related data of interest. It is unique in its ability to recognize four types of mtDNA data, to process data in batch mode and to allow access without login requirement. We hope that this tool is helpful for mtDNA studies including molecular anthropology, population genetics, forensics and biomedical research.   Update News»