Why Mitochondrial DNA is Important to Genealogists

Genealogists seek out information about their relatives and ancestors. They want to know how everyone is related to each other and to “fill in the blanks” where information is missing. Mitochondrial DNA can help genealogists discover new relatives, find out more about their heritage, and provide matrilineal information.

Mitochondria is part of a cell. Its main function is to convert energy from food into a form that the cell can use. The process is called oxidative phosphorylation. Mitochondria also can help regulate apoptosis (which is the self-destruction of cells) and are necessary for the production of cholesterol and part of hemoglobin.

Mitochondrial DNA is also referred to as mtDNA. There are a total of 37 genes in mitochondrial DNA. The majority of them provide instructions for making transfer RNAs (or tRNAs) and also for making ribosomal RNAs (or rRNAs). Both of those types of RNA can take amino acids and assemble them into functioning proteins.

Genealogists who want to learn more about their mitochondrial DNA can make use of a mtDNA test. This type of test can trace a person’s matrilineal ancestry. Every person gets his or her mtDNA from their mothers. Fathers cannot pass mtDNA to their children.

This means that information about a person’s mtDNA can help a genealogist to locate other people who match their matrilineal ancestry. The mtDNA is passed from a mother to her children unchanged. A perfect match between one person’s mtDNA and that of another indicates that the two people have a common ancestor (and that the ancestor is female).

Genealogists can run into “roadblocks” when they try to research their female ancestors. If the ancestor got married, she more than likely changed her surname. What was that ancestor’s “maiden name”? That information can be found on her birth certificate. If her original surname cannot be found, it could cause an entire branch of a family tree to be lost to history.

Genetic testing that involves mtDNA is an opportunity for genealogists to connect to those missing branches. The test results can identify the genealogist’s mtDNA and use it to identify the genealogist’s female ancestors. It can only go so far, though, because it is possible for mtDNA to mutations to occur. Each mutation connects with a specific haplogroup.

The other important thing to know about mtDNA testing is that both female and male genealogists can have that type of test preformed. Only women can pass their mtDNA onto their children. However, all her children will receive it, whether they are male or female. Men cannot pass their mtDNA to their offspring, but they can still have their own mtDNA tested.

Image by John Atherton on Flickr.

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