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Mitochondrial DNA, along the line of mothers

Our mitochondrial DNA (mtDNA) contains more or less 16,569 base pairs (A, G, C, T). Each of these pairs can be identified through various tests.

The complete genome of 16,569 is divided into three zones. The hypervariable regions HVR1 and HVR2 make up the control region. The rest forms the coding region (CR).

To do serious genealogy, it is imperative to sequence the entire genome of our mitochondria. This test is called a full genomic sequence of the mitochodrion (FGS / FMS).

Two persons can match on all variations found in the HVR1 and HVR2 regions, giving the impression that they descend from the same relatively recent matriarch. However, a FMS test could still reveal the existence of additional differences between them in their respective CR areas. Thus, to be sure they two persons share the same exact haplotype, a FMS test is usually needed and has the final word.

The following table indicates the various mtDNA tests available at FTDNA and their approximate prices (always check with FTDNA).
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For a first mtDNA test, it is suggested to order a mtDNAplus (HVR1 + HVR2) test. Then, look for potential matches with other persons tested at FTDNA (or MitoSearch). When you match, compare your respective line of mothers for a common mother, and if there is also a match, order a FMS for both persons to be sure.

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Mitochondrial DNA is transmitted along the line of mothers, the matrilineage. We received it from our mother who received from her own mother, and so on back from a mitochondrial Eve who was the first to have our signature. Two descendants from the same matriarch who have her in matrilineage should also share her signature. It is thus possible for two descendants to ascertain the mtDNA signature that had their most recent common ancestor (MRCA) if their matrilineal ancestry converge on this ancestor through two different daughters while sharing the exact same signature. This is called a triangulation.

Geneticists classify mtDNA into haplogroups basing themselves on the simultaneous presence (or path) of the various mutations it contains. Some haplogroups are typically European and others are Eurasian (Europe + Asia), still others are indigenous to Amerindians, &c. To know what a given haplogroup corresponds to in terms of geographical distribution, Google it.



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