mtDNA - Mitochondrial DNA - Motherline
Mitochondrial DNA, or mtDNA, is a very unique piece of DNA. It is a circle of DNA that is not found in the center of the cell with the 46 chromosomes. Instead the mtDNA is found inside the mitochondria or powerhouse of the cell. mtDNA is also unique because you only get one copy from your mother, who got it from her mother, who got it from her mother, who got it from her mother... you get the idea.
There is only one DNA testing company that offers mtDNA testing for genealogy: Family Tree DNA. They offer two levels of testing.
1. mtDNA Plus, $89* It examines two small regions of the mtDNA. It will give you haplogroup information and migration paths.
2. mtFull Sequence, $199* This test looks at the whole mtDNA sequence. It will also give you haplogroup information and migration paths. It will also give more detailed results that are useful for genealogical purposes.
(*regular price, subject to change)
If you are interested in using then mtDNA test for genealogical purposes it is recommended that you do the mtFull Sequence.
mtDNA: 2 Kinds of results
You also see "matches". These are other people who have tested their mtDNA that are exact matches or very similar to yours. These matches likely share a common maternal ancestor with you. Keep in mind that you may share the common maternal ancestor father back than geneaoigcal records.
This shows how to trace mtDNA on a pedigree chart