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Q: How accurate is mtDNA dating based on mutation counts?

A: Dating mtDNA solely on the number of mutations presents challenges due to the variable mutation rates across different branches. For instance, within certain branches under haplogroup W, there are cases where the ancient samples are 5000 years old without any mutations occurring over that period. Conversely, other branches may exhibit over 10 mutations in the same timeframe. This variability suggests that mutations alone for mtDNA age estimation can be unreliable without calibration against ancient samples or confirmed genealogical connections. The resulting confidence intervals would be broad regardless.

However, the Mtree carries significant value, especially when it includes geographic data about the earliest known matrilineal ancestor and other mtDNA anomalies. We continuously refine our approach to determining which mutations to use for constructing branches and subbranches, considering mutation rates. The complexity of backmutations also adds to the difficulty of creating an accurate Mtree.

Additionally, while the relative calculation of TMRCA  is generally accurate, the absolute TMRCA may currently be prone to errors due to these factors.

References:

For constructing the MTree YFull uses data from their customers and data from GenBank The initial version of MTree was based on the PhyloTree 17 of van Oven (18 Feb 2016). See van Oven M, Kayser M. 2009. Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation. Hum Mutat 30(2):E386-E394. PhyloTree.org. doi:10.1002/humu.20921

Also, YFull used some information from Ian Logan's website.

The formula of calculation of the phylogenetic weight of mutation based on HaploGrep principes See Weissensteiner H., Pacher D., Kloss-Brandstätter A., Forer L., Specht G., Bandelt H.-J., Kronenberg F., Salas A., Schönherr S. 2016. HaploGrep 2: mitochondrial haplogroup classification in the era of high-throughput sequencing. Nucl. Acids. Res. 2016 Apr 15; doi:10.1093/nar/gkw233

For the mtDNA haplogroup classification, YFull uses Kulczynski distance. See Kloss-Brandstätter A., Pacher D., Schönherr S., Weissensteiner H., Binna R., Specht G., Kronenberg F. 2011. HaploGrep: a fast and reliable algorithm for automatic classification of mitochondrial DNA haplogroups< Hum Mutat. 2011 Jan;32(1):25-32. doi: 10.1002/humu.21382. Epub 2010 Nov 16.

Last updated May 29, 2024.