Thursday, 5 April 2012

Major revision of the mtDNA tree

An important new paper has today been published in the American Journal of Human Genetics which proposes a major revision to the mitochondrial DNA tree. The abstract says:
Mutational events along the human mtDNA phylogeny are traditionally identified relative to the revised Cambridge Reference Sequence, a contemporary European sequence published in 1981. This historical choice is a continuous source of inconsistencies, misinterpretations, and errors in medical, forensic, and population genetic studies. Here, after having refined the human mtDNA phylogeny to an unprecedented level by adding information from 8,216 modern mitogenomes, we propose switching the reference to a Reconstructed Sapiens Reference Sequence, which was identified by considering all available mitogenomes from Homo neanderthalensis. This ''Copernican'' reassessment of the human mtDNA tree from its deepest root should resolve previous problems and will have a substantial practical and educational influence on the scientific and public perception of human evolution by clarifying the core principles of common ancestry for extant descendants.
The full paper can be read here.

Many of the sequences that were used in this paper to refine the mtDNA tree were submitted by customers of Family Tree DNA (including me!) who had taken the full mitochondrial sequence test and made their results available for research purposes. Rebekah Canada and Bill Hurst, the volunteer administrators of the haplogroup H and K projects helped with the H and K results. The authors publicly acknowledge the contribution of the genetic genealogy community in their acknowledgements: "We thank the genealogical community for donating their privately obtained complete mtDNA sequences for scientific studies and FamilyTreeDNA for compiling the data. We thank FamilyTreeDNA for supporting the establishment of the herein released website. We thank Eileen Krauss-Murphy of FamilyTreeDNA for help with assembly of the database. We thank Rebekah Canada and William R. Hurst for help with the assembly of haplogroup H and K samples, respectively."

A new mtDNA community website has been launched to accompany the paper. Anyone with full mitochondrial sequence results can upload their results to this website and get an up-to-date haplogroup assignment.

The mtDNA tree can also by seen at Phylotree which has just released Build 14 to account for the big change. Mannis Van Oven, who maintains the Phylotree website, is one of the authors of the new paper. The 4,265 mtDNA full sequence results used for this new paper, including a substantial proportion from FTDNA customers, are being added to the GenBank research database. There are already 1,237 FTDNA customer-submitted results on GenBank. Private submissions from FTDNA customers will now constitute almost half of the mtDNA sequences on GenBank.

©2012 Debbie Kennett

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