A mitochondrial DNA test will tell you about your direct maternal line (ie, your mother, your mother's mother, your mother's mother's mother, and so on back in time). The path of mtDNA transmission can be seen in this diagram on the ISOGG website. An mtDNA test can be used to find genealogical matches on the direct maternal line but also gives you a haplogroup assignment which tells you about your deep ancestry. Haplogroups are the branches of the human mtDNA tree, and the haplogroups all tend to have different geographical distribution patterns. Information on the distribution of the major European mtDNA haplogroups can be found on the Eupedia website.
The choice of mtDNA test will depend on your testing objectives. The mtDNAPlus test sequences the two hypervariable regions - HVR1 and HVR2 - where mutations are more likely to occur. There are 1,143 base pairs in the hypervariable region comprising around 6% of the mtDNA genome. The full mitochondrial sequence (FMS) test sequences all 16,569 base pairs in the mtDNA genome - HVR1, HVR2, plus the coding region where all the genes are found. With both tests your results go into FTDNA's large genealogical matching database and you will be notified of any matches at the three different levels - HVR1, HVR1+HVR2, and HVR1, HVR2 plus the coding region.
The number of matches that you can expect to have varies considerably. Some people like me have no HVR1 matches at all. At the other extreme some people, particularly in haplogroup H, the most common European haplogroup, can have over 12,000 matches at HVR1 and over 2,500 matches at the HVR1+HVR2 level. The full sequence test has only been available at an affordable price for the last few years and consequently there are currently fewer people in the database who have tested at this level. However, the matching criteria are more relaxed at the full sequence level so it is possible to have FMS matches despite having no matches at the lower resolutions. I have no HVR1 or HVR2 matches but I have two full sequence matches. Family Tree DNA have the world's largest collection of mtDNA sequences both at low resolution (HVR1 and HVR2) and at the full sequence level.1 As of today's date FTDNA have 159,015 mtDNA records in their database, of which 24,579 are FMS tests. With the price reductions we can expect the database to grow at a rapid pace.
The full sequence test is needed for matches in a genealogical timeframe. FTDNA estimate that 90% of exact full sequence matches will fall within 16 generations (around 400 years).2 However, lower resolution matches can sometimes provide clues for further genealogical research if your matches have ancestors from the same geographical area. If you start with the mtDNAPlus test you can always upgrade to the full sequence test at a later date.
For deep ancestry purposes the mtDNAPlus test will give you a base haplogroup assignment (eg, haplogroup H, haplogroup I, haplogroup U4, haplogroup U5, etc). The full sequence test will give you a more detailed haplogroup assignment with lots of extra letters and numbers after the base haplogroup. For example, I am a U4c1a and my dad is a U5a2b3. The most up-to-date version of the mtDNA tree is maintained by Phylotree. You can expect to see your haplogroup updated as new branches are discovered on the mtDNA tree. If you take the full sequence test you can also contribute your results to scientific research, and you might find that your results help to define a new branch on the tree. My own full sequence results were used in the 2012 paper by Dr Doron Behar et al which provided a major update to the mtDNA tree and introduced the concept of the Reconstructed Sapiens Reference Sequence.3
For assistance with understanding mtDNA results it's a good idea to join the relevant mtDNA haplogroup project at FTDNA. In some cases the project administrators will be able to provide you with a more detailed haplogroup assignment than that provided by FTDNA. It should be remembered that all the administrators are volunteers and some have more time than others to devote to their projects. A full list of mtDNA haplogroup projects can be found in the ISOGG Wiki.
It is astonishing to see how the cost of mtDNA testing has plummeted in the last few years. Family Tree DNA introduced the full mitochondrial sequence test (formerly known as the full genomic sequence test) in 2005 and the test was initially sold for $895 (£580). By 2009 the price had dropped to $439 (£284). Now it is possible to buy the full sequence test for roughly the same price that I paid to purchase the mtDNAPlus test in a sale back in December 2007.
FTDNA are of course not the only company offering mtDNA tests but they are now the clear market leader and offer by far the most competitive prices as well as having the advantage of the largest and most international mtDNA database. While it would be nice to support the British DNA testing companies unfortunately their prices are prohibitively expensive. Oxford Ancestors now charge £199 ($306) for a very basic HVR1 test with no facility to upgrade. BritainsDNA (which also trades as ScotlandsDNA, IrelandsDNA, and YorkshiresDNA) offer a chip-based testing service which looks at around 300 mtDNA markers from across the mtDNA genome. For a female this test costs £170 ($261). This is sufficient to give you a haplogroup assignment but the results cannot be used to check for matches and the test therefore has no genealogical utility.The BritainsDNA test is slightly better value for males as an mtDNA analysis can be purchased for £30 (446) on top of the Y-SNP test which costs £170 ($261) and analyses around 400 Y-SNPs for deep ancestry purposes. [*Update 18 June 2013: BritainsDNA introduced a new Chromo 2 test on 14 June. The mtDNA Chromo 2 test looks at around 3000 mt SNPs and costs £189 ($299). A new Y-DNA test is also available looking at over 15,000 Y-SNPs.] However, if you are interested in your deep ancestry the new Geno 2.0 test from the Genographic Project is a much better investment as it tests over 12,000 Y-SNPs along with over 3000 mtDNA markers at a much lower price than the BritainsDNA test. The Geno 2.0 chip also includes autosomal and X-chromosome SNPs. Geno 2.0 Y-DNA and mtDNA results can be transferred to FTDNA free of charge, where you can join the relevant haplogroup, surname and geographical projects. The 23andMe test is a good alternative to the Geno 2.0 test at a reasonable price if you just wish to know your mtDNA haplogroup, and your Y-DNA haplogroup if you are a male. The 23andMe test has the benefit of providing additional health and ancestry information. Both the Geno 2.0 test and the 23andMe test will give you reasonably detailed haplogroup assignments. Note, however, that, like the BritainsDNA test, neither the Geno 2.0 test nor the 23andMe test can be used for genealogical matching purposes on the maternal or paternal lines. For further information on the tests offered by the major genetic genealogy companies see the comparison charts in the ISOGG Wiki:
- ISOGG mtDNA testing comparison chart
- ISOGG autosomal DNA testing comparison chart.
- ISOGG Y-DNA testing comparison chart
It is certainly an exciting time to be involved in the world of DNA testing. The new low introductory prices mean that price is no longer a barrier. No doubt many new people will be added to the FTDNA database who hadn't previously considered testing. If you've not yet had your DNA tested then there is now no excuse for delaying! I will of course be delighted to welcome new members to my Devon DNA Project and my Cruse/Cruise/Crews/Cruwys DNA Project. I'm also hoping that one day someone will take an mtDNA test and will be an exact match for my rare U4c1a haplotype.
References
1. Congiu A, Anagnostou P, Milia N et al. Online databases for mtDNA and Y chromosome polymorphisms in human populations. Journal of Anthropological Sciences 2012 90; 1-15.
2. How do I tell how closely I am related to a mitochondrial DNA (mtDNA) match? FTDNA FAQ ID 2140.
3. Behar DM, Van Oven M, Rosset S et al. A “Copernican” reassessment of the human mitochondrial DNA tree from its root. American Journal of Human Genetics, Volume 90, Issue 4, 6 April 2012, Pages 675-684.
The following is the official press release from Family Tree DNA:
Family Tree DNA Offers mtDNA Test For $49
Groundbreaking low pricing made possible by cutting-edge Next Generation Sequencing technology that is dramatically driving down costs
HOUSTON, May 9, 2013 /PRNewswire/ -- FamilyTreeDNA.com, the genetic genealogy arm of Gene By Gene, Ltd., has lowered the price of its mid-level maternal line mtDNA test to $49, effective immediately. The company announced it will offer its mtDNAPlus product at a two-third price reduction permanently, in just its latest step toward universal access by individuals to their personal genetic data.
"This groundbreaking pricing illustrates how next generation sequencing (NGS) is changing the DNA testing landscape," Gene By Gene President Bennett Greenspan said. "For Family Tree DNA to be able to offer this test at such an affordable price would have been unheard of before NGS. We're hopeful that by lowering the price of products like our mtDNAPlus, we'll be able to expand the horizon of DNA testing and, importantly, grow our database to fuel future genetic discoveries."
Earlier this year, Family Tree DNA -- the world's largest processor of Y-DNA and full mitochondrial sequences -- dropped the price of its basic Y-DNA test for males by 60 percent, in order to eliminate cost as a barrier to individuals interested in learning more about their personal genetic and genomic data.
Since then, the company has been working to do the same with its mtDNA test, which is applicable to both males and females and provides data on the direct maternal line by testing the mitochondria. The mtDNAPlus product tests Hypervariable Regions 1 and 2, or HVR1 and HVR2, providing individuals with both anthropological and genealogical information.
With the largest DNA database in the world, Family Tree DNA has processed over 5 million discrete tests for more than 700,000 individuals and organizations since it introduced its Y-DNA test in 2000. Data gathered from the mtDNAPlus test will be stored, free of charge, in the company's database. If customers are interested in performing any other DNA tests that the company offers in the future, they won't be required to resubmit DNA samples.
Customer Inquiries Individuals interested in Family Tree DNA's $49 mtDNA test, or any of its ancestral testing products, can visit www.familytreedna.com or call (713) 868-1438 for more information.
About Gene By Gene, Ltd. Founded in 2000, Gene By Gene, Ltd. provides reliable DNA testing to a wide range of consumer and institutional customers through its four divisions focusing on ancestry, health, research and paternity. Gene By Gene provides DNA tests through its Family Tree DNA division, which pioneered the concept of direct-to-consumer testing in the field of genetic genealogy more than a decade ago. Gene by Gene is CLIA registered and through its clinical-health division DNA Traits offers regulated diagnostic tests. DNA DTC is the Research Use Only (RUO) division serving both direct-to-consumer and institutional clients worldwide. Gene By Gene offers AABB certified relationship tests through its paternity testing division, DNA Findings. The privately held company is headquartered in Houston, which is also home to its state-of-the-art Genomics Research Center.