Understanding mtDNA


How do I make sense of my mtDNA results? This question gets asked a lot. To help answer that question, I have pulled several articles from FTDNA "Facts and Genes". In time, I hope to put this in more readable form.

Once you understand the basics, you may also want to go to our mtDNA - The Family of Woman page and see the projects and websites are focused on your haplogroup. http://www.worldfamilies.net/reference_mtDNA

 


The following three articles were copied verbatim from " Facts & Genes" from Family Tree DNA


Facts & Genes from Family Tree DNA
==================================
March 28, 2005 Volume 4, Issue 2


Understanding Your Results: mtDNA
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Occasionally, the mtDNA Haplogroup can not be predicted from the mtDNA result. When this occurs, on your mtDNA Results Page, a dash (-) will appear where the Haplogroup should appear. Tests are then run, called RFLP tests, to determine the Haplogroup. (RFLP stands for restriction fragment length polymorphism.) When the results are back for this test, the Haplogroup will appear on your mtDNA Results page.

The mtDNA test is available in 2 versions. These tests are called:

mtDNA
mtDNA Plus

The test called mtDNA provides a result for the region of mtDNA called HVR1. The test called mtDNA Plus tests two regions of mtDNA, the regions called HVR1 and HVR2.

If you want to find mtDNA matches in a genealogical time frame, select the mtDNA Plus test.

If you have taken the mtDNA test, and want to reduce the time frame for the common ancestor for your matches, you can upgrade your test to the mtDNA Plus test. Upgrading to the mtDNA Plus test is also recommended for all results who match the reference standard, called CRS, or Cambridge Reference Standard.

To upgrade your mtDNA test, on your Personal Page, click on Order Tests.

Haplogroup H comprises about 40% of the mtDNA in Europe. If your mtDNA Haplogroup is H, an additional test, the Haplogroup H sub-clade test, is available, which will tell you more information. To learn about what you can discover with the Haplogroup H sub-clade test, do the following. On your mtDNA Results Page, click on the link "Click Here if you are Haplogroup H", which is right below the link "Understanding Your Results". This link will tell you what you can discover with the Haplogroup H subclade test. To order the Haplogroup H subclade test, click on the link "click here to order" to the right of your mtDNA results, on your mtDNA Results Page.

Anyone with an understanding of family history research can utilize DNA testing. It isn't necessary to have a scientific background. The few scientific terms you will encounter will be explained.

You can discover information about your direct maternal line with an mtDNA test. This would be your mother, her mother, and so forth back in time. Both men and women inherit mtDNA. Only women pass on mtDNA.

To order a mtDNA test, you can order as part of a Surname Project, or as an individual. To order as an individual, click on the link below:

http://www.familytreeDNA.com/products.html

For more information, see the articles below:

Understanding Your Results: mtDNA Matches
http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=3.2

Understanding Your Results: mtDNA Haplogroups
http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=3.1



Facts & Genes from Family Tree DNA
==================================
March 3, 2004 Volume 3, Issue 2

Understanding Your Results: mtDNA Matches
=========================================

Both males and females inherit mtDNA, and only females pass on mtDNA. Your mtDNA represents your direct female line, which would be your mother, her mother, and so forth. Therefore, both males and females can take the mtDNA test, to learn about their direct female line. Your mtDNA can be traced back thousands or 10's of thousands of years to a specific Haplogroup. Your mtDNA Haplogroup defines which of these females was your very distant ancestor, popularly known as Daughter of Eve or Clan Mother.

There are two mtDNA tests available from Family Tree DNA:
mtDNA
mtDNA Plus

The test called mtDNA will test one region of mtDNA providing the results for this region, and identifying your Haplogroup. The mtDNA Plus test includes the mtDNA test, and also tests a second region of mtDNA. These regions of mtDNA tested are called HVR-1 and HVR-2. HVR stands for Hyper Variable Region, and is known interchangeable as Hyper Variable Segment, or HVS.

HRV1 and HVR2 are known as the 'control region' are areas of mtDNA that contain no personal information (i.e. HVR-1 and 2 are not part of the 'coding region') and have the fastest rate of change, or mutation, of any region in mtDNA. That is why the Anthropological community has focused on them for population genetics.

Even though HRV1 and HVR2 provide the fastest mutation rates for mtDNA, the rate of change is much slower than the Markers tested on Y DNA. The mtDNA test is often called an anthropology test, since mtDNA mutates very slowly, much more slowly than the locations tested on the Y chromosome. For this reason, only exact matches are provided when you click the "mtDNA Matches" selection on your Personal Pages at Family Tree DNA. Simple put miss matches on mtDNA have no potential for genealogical value.

Since mtDNA mutates very slowly, if you are interested in finding matches to others, or using mtDNA for genealogy purposes, it is important to take the mtDNAPlus test. If you have already taken the mtDNA test (formerly known as Maternal Match), you can upgrade to the mtDNA Plus test. The addition of testing the second mtDNA region, HVR-2, will shorten the lengthy time frame of any matches. If you have taken the mtDNA test, you can easily upgrade to the DNAPlus test. On your Personal Page at Family Tree DNA, click on the link 'Order Tests'.

If you only take the mtDNA test, those who you match randomly are most likely not related in any genealogical time frame. If you are looking to find others who are related in a genealogical time frame, then it is essential to take the mtDNA Plus test.

The chart below shows the time frame of the common ancestor for a random match.


Test Time frame of common ancestor for a match
============= ===========================================
mtDNA 50% of the time, 52 generations or less
mtDNAPlus 50% of the time, 28 generations or less


These time frames are for random matches. When you are utilizing mtDNA testing for genealogical purposes, you have identified the ancestors or potential ancestors, so the time frames shown above are not relevant.

The results for a mtDNA test tell you about your most distant female ancestor, who might be popularly known as a Clan Mother. You can take a mtDNA test to learn about your direct female line. If you are at all interested in finding genealogically relevant mtDNA matches, it is important to take the mtDNA Plus test.

For more information about mtDNA testing, see the last issue of Facts & Genes:

http://www.familytreeDNA.com/facts_genes.asp?act=show&nk=3.1

To order a mtDNA test, click on the link below:

http://www.familytreedna.com/products.html


Facts & Genes from Family Tree DNA
==================================
January 22, 2004 Volume 3, Issue 1


Understanding Your Results: mtDNA Haplogroups
=============================================

Each mtDNA Haplogroup represents all those persons descended from one of the Clans, actually subdivisions from the female that we all descend from...In lay terms, the mtDNA Haplogroup is often referred to as the "Daughter of Eve" or the "Clan Mother".

Each of these females or clan mothers now have millions of descendents today, who are all identified as belonging to the same Haplogroup, althoigh their specific DNA signature may vary.

Humans originated in Africa about 120,000 to 150,000 years ago. The original female to exist in Africa is known as the Mitochrondrial Eve. The "Clan Mothers" or "Daughters of Eve" are descendents of this original Mitochrondrial Eve.

Scientists have identified a few dozen mtDNA Haplogroups around the world, and more mtDNA sub Haplogroups could be discovered as the scientists research remote populations.

mtDNA Haplogroups are identified by letters of the alphabet, and some of these Haplogroup labels also have numbers. When a subgroup is identified a number is placed directly after the letter, for example J1 indicates that at least 1 specific subgroup for J has been identifed.

Below are some of the Haplogroups for mtDNA:

A, B, C, D, F, G, H, I, J, K, L, L1, L2, L3, T, U, V, X


Each mtDNA Haplogroup originated in a different geographic area, thousands of years ago. For example, it is known that Haplogroup H originated in Europe, and was involved in a population expansion about 20,000 years ago. Over time, populations migrated, and Haplogroup H is now spread out over Europe, and about 40% of all Europeans belong to mtDNA Haplogroup H. Haplogroup U5 is the oldest European lineage, dating about 50,000 years ago, and may have come in contact with Neanderthals living in Europe at the time.

The classification of mtDNA Haplogroups should not be confused with the classification of Y DNA Haplogroups. Y DNA and mtDNA each have a separate system for classifying the respective Haplogroup. Y DNA Haplogroups are based on a test of the Y chromosome, and mtDNA Haplogroups are based on a test of mtDNA. Even though Y DNA has an A Haplogroup, and mtDNA has an A Haplogroup, these Haplogroups are completely different.

Both males and females inherit mtDNA, and only females pass on mtDNA. Your mtDNA represents your direct female line, which would be your mother, her mother, and so forth. Therefore, both males and females can take the mtDNA test, to learn about their direct female line. Your mtDNA can be traced back thousands of years to one of the original females. You Haplogroup defines which of these females was your ancestor.

Your mtDNA Haplogroup will tell you some information about the general geographic area where you Daughter of Eve originated or at least where that Haplogroup is most commonly found today:

Southern Europe: J, K
Northern Europe: H, T, U, V, X
Middle East: J,N
Africa: L, L1, L2 and L3.

Asia: A, B, C, D, F, G

Native American: A, B, C, D and sometimes X

mtDNA Haplogroup X is found in Europe and Asia, and is believed to have migrated to the Americas about 15,000 years ago, making up a very small component of the Native American population.

The mtDNA Haplogroup descriptions at Family Tree DNA provide additional information about your mtDNA Haplogroup.

There are two mtDNA tests available from Family Tree DNA:
mtDNA
mtDNA Plus

The test called mtDNA will test one region of mtDNA and provides the results for this region, and identify your Haplogroup. The mtDNA Plus test includes the mtDNA test, and also tests a second region of mtDNA. These regions are called HVR-1 and HVR-2, and are known as HV (Hyper Variable) Segment or HV Region. The HVR1 and 2 tests look at mutations with teh control region of yoru mtDNA...an area of teh mtDNA that is not known to 'code' for anything and enjoys teh fastest mutation rate of any region in the mtDNA. The scientists use both the terms HV Segment and HV Region, and you may well find these terms used interchangeable, as well as the associated abbreviations.

In summary:


Test What is Tested
---------- -------------------------------------
mtDNA HVR-1 and determines the Haplogroup
mtDNA Plus HVR-1, HVR-2 and determines the Haplogroup


Occasionally, an ancient human has been discovered and their mtDNA tested, such as the Ice Man. The 5000 year old Ice Man belongs to Haplogroup K. The Cheddar Man belongs to Haplogroup U.

The mtDNA test is often called an anthropology test, since mtDNA mutates very slowly, much more slowly than Short Tandem Repeats (STR's) that we test with the Y chromosome. The results for a mtDNA test tell you about your most distant female ancestor, or Clan Mother.

The mtDNA test, besides telling you about your very distant direct female ancestor, can also be used to confirm genealogical relationships. If two persons are linked by a common female ancestor, then their results from the mtDNA test will match exactly. The two persons could be either male or female, as long as the male's mother belongs to the direct female line being tested.

Since mtDNA mutates very slowly, if you are interested in finding matches to others, or using mtDNA for genealogy purposes, it is important to take the mtDNAPlus test. If you have already taken the mtDNA test (Maternal Match), this test can be upgraded to the mtDNA Plus test. The addition of testing the second mtDNA region, HVR-2, will shorten the time frame of any matches.

It is highly recommended that the mtDNAPlus test be ordered by those persons interested in a genealogical application, or for matching. mtDNA has a very slow mutation rate. The chart below shows the time frame of the common ancestor for a random match.



Test Time frame of common ancestor for a match
============= ===========================================
mtDNA 50% of the time, 52 generations or less
mtDNAPlus 50% of the time, 28 generations or less




These time frames are for random matches. When you are utilizing mtDNA testing for genealogical purposes, you have identified the ancestors or potential ancestors, so the time frames shown above are not relevant.

mtDNA test results show the Haplogroup, and the mutations compared to the standard, which is called the Cambridge Reference Sequence (CRS). The CRS is simply the first mtDNA sequenced, so all results are presented as the mutations compared to this standard.

Since mtDNA mutates, or changes, very slowly, the Matching selection at familytreeDNA.com only provides exact matches, since partial matches are not genealogically relevant.

You mtDNA goes back further than any written record. To order a mtDNA test, click on the link below:

http://www.familytreeDNA.com/products.html


The above three article were copied verbatim from " Facts & Genes" from Family Tree DNA

http://www.familytreedna.com/facts_genes.asp?act=past