Copyright © August 2004, Revised 2006, 2007, 2015
Mary Fern Souder
The mitochondrial DNA (mtDNA) test examines DNA in the mitochondria of the cells. This analysis examines entire section of the DNA, protein by protein. DNA is composed of four chemicals, Adenine, Cytosine, Guanine, and Thymine, which are repeated in various patterns.
A size-comparison of mitochondrial DNA vs. the Y-chromosome (which is tested for men), is that the mitochondria is the size of a little town, and the Y-chromosome is long enough to reach across the United States. Thus, only certain spots or "snippets" of the Y-chromosome are tested for men, whereas, an entire block of the mitochondrion is analyzed.
The mitochondrion was first sequenced in 1981 in England at Cambridge University, and the sample used was that of one of the English scientists.† The results of this person's analysis were known as the Cambridge Reference Sequence (CRS), and the CRS become the world standard for comparison of all subsequent persons who did mtDNA testing.† Any value which differed from this standard was designated a mutation.† This obviously was an artificial standard, but nonetheless served as the benchmark (with slight modifications known as the Revised Cambridge Reference Sequence (RCRS), against which all others were compared for the next 31 years.
However, after a reassessment of a much larger and globally diverse population, in 2012 Dr. Doron Behar and his team of scientists published the Reconstructed Sapiens Reference Sequence (RSRS).† Use of this standard has resulted in those of Western European descent showing more mutations than when previously compared to the British scientist.† The RSRS is now (at least until 2015) the standard against which all worldwide mtDNA results are compared.† To accommodate those who did early mtDNA testing, FTDNA provides two sets of results so that participants can see both their old RCRS and their new RSRS results. Regardless of which sequencing model is used, a personís matches will be to the same identical persons (who also will be able to see their results using both models.
Due to the huge expenditure of time that would be required for reprogramming and replacing CRS results with RSPS in this study, this procedure will not be undertaken.† Anyone who matches the RSPS results of any participants in this study will be sent an automatic notice of their match.
There are three components to mtDNA testing: Hypervariable Region 1 (HVR1) containing 569 base pairs, Hypervariable Region 2 (HVR2) containing 574 base pairs, and the Coding Region. The results of all three tests are known as the Full Mitochondrial Sequence (FMS). Mutations which occur are either a substitution in the sequence, an insertion in the sequence, or a deletion in the sequence.† A few of the participants in this family study have upgraded to the FMS, but most have not.
MtDNA is passed from a mother to all of her children of both genders. The mother and child will have an identical mtDNA sequence except for some rarely occurring mutations. Therefore people who can trace their ancestry back through an unbroken string of female predecessors to a common female ancestor will have identical or very similar mtDNA sequence.
Because I believe that our maternal ancestors are equally as important as our male ancestors, participants who carry the mtDNA of our remote grandmothers have been included in this study. The mtDNA contributed by some of the participants was of a very common type, and have numerous matches in the ftDNA database. Others, however, seem to be much less common, and have no perfect matches at this point.
Studies have emerged which track the various mitochondrial haplogroups (or clades) to geographic regions. Haplogroups are also associated with racial identity. Caucasian haplogroups include U, H, K, N, T, I, J, X, V, and W. Native American Indian haplogroups include A, B, C, D, and X. Asian haplogroups include A, B, C, D, and M. African haplogroups include L1, L2, and L3, and M.
Haplogroup H is the most common mtDNA haplogroup in Europe, where up to 48% of all women fall into this category. Participants who have tested their Full Mitochondrial Sequence will have a more definitive result, eg. H5a1 as compared to H5, or K1c2 as compared to K1.††
I was especially pleased that results of mtDNA testing for four of our early female ancestors established a missing link between them and a suspected earlier ancestral line.† These women were Catherine Fine, Catherine Johnson, Margaret Mashburn, and Rhoda Strain. In each case, the women were closely associated with another woman who carried the same maiden name and who did have a documented paper trail back to an earlier lineage.
As you click on the link for each of the mtDNA lineages presented below, you will see how many maternal matches have been reported to FamilyTreeDNA for each individual as of October 2015, after 14 years of testing. The number of matches is reported only in order to give an idea of the frequency that this unique mtDNA signature appeared in the FTDNA database as of 2015, and due to time restraints I will not continually update the number of matches.
If you think that you may be a member of our family and would like to contribute an mtDNA sample, you may obtain a kit at the following FTDNA site: FTDNA.
Last Updated on 10/9/2015
By Wallace W. Souder