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Maternal Bond: Understanding Your mtDNA Results

Overview

 

DNA testing companies offer three basic types of tests: autosomal DNA, Y-DNA, and mitochondrial DNA (mtDNA). Mitochondrial DNA tests trace people’s matrilineal (mother-line) ancestry through their mitochondria, which are passed from mothers to their children. Since everyone has mitochondria, both males and females can take mtDNA tests. Mitochondrial DNA testing uncovers a one’s mtDNA haplogroup, the ancient group of people from whom one’s matrilineage descends. Because mitochondria is passed on only by women, no men (nor their ancestors) from whom one descends are encapsulated in the results. This test provides a list of matches who share common direct maternal ancestry within 52 generations.

 

Three companies currently offer mtDNA testing: FamilyTree DNA, 23andMe, and LivingDNA. However, only Family Tree DNA holds matching databases for Y DNA, mtDNA and autosomal DNA. This means that if you’re hoping to find living relatives on your maternal line, you’ll only be able to do this with a Family Tree DNA mitochondrial DNA test. Other companies with a “family finder” feature only hold matching databases for autosomal DNA, even though some of these companies may test your mitochondrial DNA to produce your maternal haplogroup (such as 23andMe). In these cases, the living relatives they identify will be matched according to your autosomal DNA, not your mitochondrial DNA. This means you will share ancestors with these relatives, but you’ll be unable to tell if they share your maternal lineage.

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Human Migration based on Mitochondrial DNA (mtDNA) Haplogroup (Click to download)

DNA Science


The Reconstructed Sapiens Reference Sequence (RSRS) is a mitochondrial DNA (mtDNA) reference sequence that uses both a global sampling of modern human samples and samples from ancient hominids. Since the RSRS is based on the likely modal haplotype of the common ancestor to both modern humans and such ancient groups as the Neanderthals, it shows an unbiased path back from any one modern mtDNA sequence to our distant common maternal ancestor.
The coding region (CR) is the part of your mtDNA genome that contains genes. Because it does contain some genes, the coding region is believed to be slower mutating than the control region. Often, the mutations that are found in the coding region are used to define haplogroups. 

 

The mtDNA has two major sections: the control region and the coding region. The control region is often called the hypervariable region (HVR). Hypervariable means fast changing. In mitochondrial DNA, the control region is the fast changing part. The control region may be further divided into two hypervariable regions, HVR1 and HVR2. 

Sample hypervariable region (HVR) and coding region differences based on chromosome of common maternal ancestor 

Test Results


Your results will compare the sequences from both your HVR and haplogroups to other people in the database.  Matches at higher levels are more likely to be recent. The only way to find a connection with your match is by comparing your genealogies. In many cultures, women changed names with marriage. Therefore, it is important to compare geographic locations alongside genealogical information and surnames. To find connections in recent times, it is necessary to find and test multiple people who have suspected shared ancestry. You can do this by careful examination of traditional genealogical records. Making connections with people in genealogical and historic interest groups can also be helpful.

One member of the Clan Forbes Society has agreed to share his mtDNA results from Family Tree DNA so that you can understand how this testing can be useful to your genealogical research. Family Tree DNA determined that Mr. Forbes shares the Haplogroup “J1c3b2.” The original haplogroup “J” originated in the Near East approximately 50,000 years ago. Within Europe, the sub-lineage of haplogroup “J1” is found distributed throughout Europe, from Britain to Iberia and along the Mediterranean coast. This widespread distribution strongly suggests that haplogroup “J1” was part of the Neolithic spread of agriculture into Europe from the Near East beginning approximately 10,000 years ago. Halpogroup “J1c3” is projected to have first appeared in about 7000 BCE and Haplogroup “J1c3b” appeared between about 4500 BCE and 400 AD in Ireland. 
This is not surprising since Gaelic invaders from northern Ireland (called "Scoti" by the Romans) created the overkingdom of Dál Riata  (also called Dalriada) in the islands and highlands of Scotland. In the 6th and 7th centuries, Dalriadic warriors pushed eastward into Pictland (now Aberdeenshire) and intermarried with the Picts. (See Origins of the House of Forbes.) 


As noted, the control region of the mtDNA is divided into two hypervariable regions, HVR1 and HVR2. Part of the test results of Mr. Forbes indicates differences from the RSRS (control gene of a common ancestor) in specific sections of these two regions. These specific differences can be matched with other people in the mtDNA database to indicate the “closeness” of their genetic match to Mr. Forbes. 

Impact on Genealogic Research

In the first two months since taking the test, Mr. Forbes has discovered 7 mtDNA relatives with a “genetic distance” of “0” (very close) and 20 relatives with a distance of “1.”

 

Each of the names on the report can be researched for the names of the maternal line – if they have been entered.

In fact, Family Tree DNA has a Scottish mtDNA Project, primarily for individuals who have an unbroken Scottish lineage on their direct matrilineal line of descent. The project Administrators and Co-Administrators are categorizing the 8,000 members by haplogroup. One Co-Administrator has requested Mr. Forbes’s assistance by submitting as much information on the maternal line as possible, including given name, birth or maiden surname, year of birth and/or death, and place of birth.


While, Mr. Forbes has researched his paternal line of Forbes, he has a great deal of research ahead to flesh out the maternal side of his ancestry. However, his mtDNA test results has given him a huge advantage in accomplishing that. Stay tuned!


What have you learned from your mtDNA results? Share your story with the Clan Forbes Society!