Reference Mt-DNA molecule (maternal line non-nuclear DNA - located inside cells but
outside the nucleus) nucleotide (SNP) mutation rate:
3.0 x 10^-5 or .00003 per nucleotide transmission event (birth of a new generation) is a commonly used value
for D Loop HVR regions. The 0.00003 one significant digit
average mutation rate I'm using in this overview is based on the work by Parsons, A High Observed
Substitution Rate in the Human Mitochondrial DNA Control Region, Nature Genetic, Vol. 15, April 1997, pp. 363-367.
That report determined a rate of about 2.9 x 10^-5 .
Typical Average Mt-DNA (maternal line) Haplotype Mutation Rate (mtsnpHMR)
Reference Mt-DNA (maternal line) haplotype (HVR1 Region) mutation rate (mtsnpHMR540):
.000030 x 540 nucleotides (markers) in HVR1 region tested = .0162 per transmission event (birth of a new
generation). Thus an HVR1 mtDNA haplotype can easily survive unchanged for about 62 generations (about 1550 years).
This is about 4.6 times slower than the typically used commercial Y-STR paternal line haplotypes mutate. Thus the common
female ancestor (MRCA) of two people who randomly match exactly for the HVR1 region mtDNA haplotype usually long predates
a time frame of relevant genealogical interest, i.e., long before the last 500 years. Therefore using mtDNA in a
random search for matching maternal lines will lead to many wild goose chases. But mtDNA can be used to verify pre-existing
traditional genealogy evidence that two maternal lines are related, i.e., the direct maternal line of descent of two
families is thought to be from two women who are surmised to be sisters from prior paper trail or oral history evidence.
But be prepared for numerous random matches with lines not recently related with mtDNA (maternal line) testing.
Reference Mt-DNA (maternal line) haplotype (HVR1 and HVR2 regions) mutation rate (mtsnpHMR1050):
.000030 x 1050 nucleotides (markers) in HVR1 and HVR2 regions tested = .0315 per transmission event (birth of a new
generation). Thus a combined (HVR1+HVR2) mtDNA haplotype can easily survive unchanged for about 32 generations (about 800
years). This is about 2.4 times slower than the typically used commercial Y-STR paternal line haplotypes mutate. Thus the
common female ancestor (MRCA) of two people who randomly match exactly for the combined HVR1+HVR2 mtDNA haplotype usually long
predates a time frame of relevant genealogical interest, i.e., long before the last 500 years. Therefore using mtDNA in a
random search for matching maternal lines will lead to many wild goose chases. But mtDNA can be used to verify pre-existing
traditional genealogy evidence that two maternal lines are related, i.e., the direct maternal line of descent of two
families is thought to be from two women who are surmised to be sisters from prior paper trail or oral history evidence.
But be prepared for numerous random matches with lines not recently related with mtDNA (maternal line) testing.
Using a TMRCA Calculator with mtDNA Test Results
to get an Estimate Range for when the mtDNA Most Recent Common Ancestor Lived
Get the mtDNA test results for two people and compare their results.
Here is an example using my mtDNA test results for the HVR1 + HVR2 regions
and another semi-randomly selected person from the Mitosearch.org public database. My Mitosearch ID is FV9RZ. My mtDNA
haplogroup is H1a. For the HVR1 + HVR2 regions I have six mutational differences from the CRS. I semi-randomly picked
another H1a person in the Mitosearch.org database to compare myself to. I picked Mitosearch ID 739SP. That person
has a total of seven mutational difference from the CRS. But the mutations for each of us are not exactly the same ones.
See this comparison table from Mitosearch.org:
Print out the table and cross off the mutations shared by both individuals leaving the mutational differences between
the two mtDNA haplotypes remaining. In the above case that leaves a mutational difference of three, i.e., for the 1050
mtDNA nucleotide markers tested the two of us differ at three locations. Thus for 1050 markers tested we matched
at 1047.
Number of markers: 1050
Number of markers that match: 1047
Mutation rate: 0.00002 if using the rate mentioned in McDonald's page or 0.00003 per my discussions listed above.
Check the Cumulative Probability box. I prefer to use the cumulative display myself.
Click on the Create Graph or Create List button and the results will be displayed. Interpret the results using
the guidance provided in Doug McDonald's webpage.
Note: Per the instructions on Doug McDonald's page, divide the number of Transmission Events (births) displayed for
the probability of your choice (most typically choose and quote the 0.50 point) by two to get the number
of "generations" back to the MRCA for
that probability confidence level. Then using 25, 30, or 32 years per generation (your preference), multiply the number
of generations times the number of years per generation to get the Time to Most Recent Common Ancestor (TMRCA) for
these two mtDNA haplotypes with a 50% confidence level that the time is no greater than that.
For the Mitosearch data example and using the 0.00003 mtDNA mutation rate, and eyeballing the chart or looking at the table, the cumulative
probability reaches 0.50 (50%) at roughly 116 transmission events (births). 116 divided by two equals 58 generations.
58 generations times 25 years per generation yields 1450 years. Thus there is a 50% probability that the mtDNA Most Recent
Common Ancestor (MRCA) for these two haplotypes lived in the last 1450 years and there is a 50% probability that she lived more
than 1450 years ago.
For the Mitosearch data example and using the 0.000025 mtDNA mutation rate, and eyeballing the chart or looking at the table, the cumulative
probability reaches 0.50 (50%) at roughly 140 transmission events (births). 140 divided by two equals 70 generations.
70 generations times 25 years per generation yields 1750 years. Thus there is a 50% probability that the mtDNA Most Recent
Common Ancestor (MRCA) for these two haplotypes lived in the last 1750 years and there is a 50% probability that she lived more
than 1750 years ago.
For the Mitosearch data example and using the 0.00002 mtDNA mutation rate, and eyeballing the chart or looking at the table, the cumulative
probability reaches 0.50 (50%) at roughly 176 transmission events (births). 176 divided by two equals 88 generations.
88 generations times 25 years per generation yields 2200 years. Thus there is a 50% probability that the mtDNA Most Recent
Common Ancestor (MRCA) for these two haplotypes lived in the last 2200 years and there is a 50% probability that she lived more
than 2200 years ago.