mtDNA Testing for Genealogy
The basic science:
- The mtDNA test can be used for testing both females and males.
- Only females can pass their mtDNA on to their children.
- The mtDNA test uses information from the mitochondria, which is the material that surrounds the chromosomes.
- mtDNA is passed from a mother to her children, essentially unchanged. (If there were no changes, each person would have exactly the same mtDNA as "Eve" and with each other.)
- This test is only useful in testing the participant's mother's mother's .... mother's line.
- All people who share the same "common ancestor" will carry essentially the same mtDNA and receive tests results that are also essentially the same.
How it works
- The laboratory examines the DNA sample and uses standardized protocols to test the mtDNA.
- The results are typically reported by designating only the differences to the Cambridge Reference Standard.
- Using these differences, scientists have been able to group all people into major branches called "Haplogroups".
- Results and matches are posted on the participants personal "myFTDNA" page at www.familytreedna.com
- By comparing results, we can draw conclusions on which maternal lines share a common ancestor.
- As this line changes names every generation, it is relatively difficult to track more than a few generations through genealogy.
Why mtDNA testing is useful
- It follows only the maternal line--your mother's mother's mother's line.
- While not as easy to trace as the yDNA surname matches, some mtDNA matches are able to identify common ancestor.
- You will learn your maternal Haplogroup, which will tell you the ancient geographic and ethnic origins of your maternal line.
- You will be able to join an mtDNA Haplogroup Project, to work with others who share your ancient origins.
- You will be able to join a surname project using your mtDNA results. Although only yDNA results are useful in a surname project, by joining you will receive updates about the project, be included in the research, and be able to submit a family pedigree.
The rules for mtDNA testing
- Males or females can take the mtDNA test.
- The test traces your maternal line (your mother's mother's mother's...line).
- You can join a Surname DNA Project if you have been mtDNA-tested, but your mtDNA results are not useful in a Surname DNA Project.
- If you want to test for Native American or Jewish Ancestry, you must make sure the mtDNA test taker has a direct maternal line (through females only) back to the ancestor of interest.
mtDNA Haplogroups:
- Haplogroups are used to represent the major branch points on the mitochondrial phylogenic tree.
- There are random and subtle changes that allow us to see differences in different "genetic families".
- These can be arranged into a "family tree of woman" that shows the different branches that have separated over 1000s and 10,000s of years.
- Each person today can be assigned to a Haplogroup, which tells her (or him) their "deep ancestry".
- Haplogroups are determined by looking at mutations.
- The letter names of the mtDNA Haplogroups run from A to Z, and were named in the order of their discovery.
- mtDNA Haplogroups are not the same as yDNA Haplogroups.
Mutations
- mtDNA is passed from mother to child "essentially unchanged". However, on a random, but predictable basis for a large group, minor changes occur that we call "mutations".
- We cannot predict when these mutations will occur in an individual family, but we do know that a mutation that occurs in one woman will be passed on to her children - and that her daughter will pass it on to their children, and so on ....
- These mutations have occurred through the centuries, giving us the Haplogroups mentioned above,
- These mutations occur less frequently than in yDNA, which makes them less useful in genealogy. Our genealogical paper trails usually extend a few hundred years on our maternal line, with a fortunate minority having paper trails reaching back further.
- Many people carry mtDNA which had not experienced a mutation in the past 1000 years.
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