Mitochondrial DNA ("mtDNA") testing is a test which has been around for many years. It focusses on the maternal line.
As with the Y chromosome, which is passed from a father to his sons unchanged, mtDNA is passed from a mother to her children unchanged.
Mitochondrial DNA is located outside the nucleus of each of the cells in the body, in the cytoplasm.
Both males and females can take this test, as mitochondrial DNA is passed from a mother to both her male and female children, virtually unchanged through the generations.
Genetic genealogists have assumed that any mutations which do occur, do so at a predictable rate, leading to the ability to estimate how far back a common female ancestor was in relation to two descendants.
However, new research has shown that some areas of mitochondrial DNA mutate much faster than others, so that the range of error for the time period of the most recent common ancestor using mitochondrial DNA is broader than previously thought.
Got a story about mtDNA to tell? Click here.
Since surnames are not passed from mother to child as they are from father to son, it is more difficult to trace relatives and ancestors along the maternal line. (Not that that is the fault of the test!)
Also, the test currently has a large margin of error, with significant blind spots. One such blind spot is the confusion of Mongolian ancestry with Native American ancestry.
Another limitation is that this test looks only at your own maternal line. If you wanted to find out about your father's mother, for example, you could not be tested, as you did not inherit her mitochondrial DNA. The mtDNA would have passed from his mother to all of her children, and from any of her female children to their children. So, you would have to convince your father or one of his siblings, or one of your father's sister's children, to take the test.
The latter drawback appears to be changing, however. The Family Tree DNA website offers a test called the "Family Finder Test". And a most interesting concept it is! Please see my webpage Autosomal DNA Testing for more details.
The usefulness of this test was demonstrated in the case of Russian Tsar Nicholas, who, along with his family and a number of servants, was murdered in 1917, reportedly on the orders of Lenin. Their bodies were disposed of at one site, and then moved to another when rumours spread of the original burial site.
When the actual burial site finally was found in 1991, nine bodies were disinterred. DNA samples were sent to the UK and the US. The results of DNA testing indicated that five of the skeletal remains were from one family (2 parents and 3 children), and four were unrelated.
The mother's mitochondrial DNA analysis revealed links to the British royal family, which was consistent with Tsarina Alexandra’s heritage. Britain’s Prince Philip, a descendant of Alexandra’s sister Victoria, provided a DNA sample. His mtDNA matched that of the skeletal remains of the mother and the children.
The father’s Y-DNA was an exact match to the remains of Nicholas' brother George, whose body was disinterred to obtain a DNA sample.
These results, published in December of 2008, proved conclusively that the mother, father, and three daughters were the Tsar, his wife, and three of their five children.
The other two children's remains later were found nearby, and DNA analysis confirmed their relationship to the Tsar and his wife, and therefore their identities. This has laid to rest the persistent rumours over many years that at least one of the children had escaped the assassination.
In a case involving less famous people, an African American woman was researching her female ancestry line. She had managed to trace her grandmother and great-grandmother.
Both had been slaves, and it was very difficult to find out much about them, as most slaves were documented only rarely, and then not as humans, but as property of their owners.
She therefore had hit a brick wall, and was unable to trace her family tree any farther back.
With mitochondrial DNA testing, she discovered that her mtDNA was commonly found in south-west Africa. It therefore was not unreasonable to infer that she had a female ancestor from that area who had been captured and forced into slavery.
She also was provided with a number of surnames and e-mail addresses of others whose testing showed they had the same mtDNA haplogroup, and therefore could be related to her.
Hopefully, when they pool their knowledge and research, she will be able to fill in at least some of the blanks, and discover some genetic relatives, as well as move farther back in her family tree!
This type of testing is widely available in North America. Many US companies specializing in DNA analysis will provide services to Canadians, although some companies have operations in Canada as well.
For a list of the seven largest 'players' offering mtDNA analysis and comparing their testing services, click here.
Orders can be placed online or by telephone, and kits will be sent out to the address specified.
As with the Y-chromosome testing, it sometimes is difficult to tell just what regions of the mitochondrial DNA are being tested in the descriptions offered online.
In the US, as of early 2011, prices for mtDNA testing at the HVR1 and 2 sites range from US$159 to US$179. Testing at the HVR1, 2, and 3 sites range from US$199 to US$395.
In Canada, prices range from C$139 for HVR1 testing, to C$219 for HVR1 and 2, and C$350 for HVR1, 2, and 3.
These prices are, of course, simply guidelines, and it is very likely that there are higher-priced and lower-priced products in every category. Also, some companies offer a “bundling” price, if you purchase two or more tests at the same time.
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