Relationship DNA testing: The Mitochondrial DNA (MtDNA) test

14 Aug 2017

Advances in the fields of genetic testing means that today you can do a number of DNA tests that can establish whether biological relationships exists between people. DNA testing can be carried out using two types of DNA found in human cells: nuclear DNA or mitochondrial DNA (called MtDNA for short).MtDNA testing is an important Relationship DNA test and has many advantages over nuclear DNA.

What is the difference between nuclear DNA and Mitochondrial DNA?

Nuclear DNA: this is found in the cell nucleus. Like the brain in our heads, the nucleus is the brain to our cells; it controls everything that happens. Each cell contains one nucleus and in it we have the DNA found on our chromosomes. Humans all have 46 chromosomes although there are abnormalities which can result in extra chromosomes. When you choose to do a paternity DNA test, an immigration test or any other DNA test that is not an MtDNA test, you send in samples that are tested for nuclear DNA. Testing nuclear DNA is very accurate and offers precise results.

Mitochondrial DNA: Mitochondria are found in thousands in a human cell and their structure is strong. As organelles they are responsible for creating energy to help the cell function. Within the mitochondria we find mitochondrial DNA. Given the fact that there are thousands in the human cell, mitochondrial DNA can be extracted from tiny samples containing just a few cells. Moreover, the fact that the structure of the mitochondrion is strong, the DNA with is very well protected and is not usually broken down by for example fire, certain chemicals and environmental conditions that would often destroy nuclear DNA.

MtDNA in Relationship DNA Testing

There are many relationships tests that can be done to find whether various types of relationships exist between people, including grandparentage DNA testing and avuncular DNA testing.

MtDNA testing is reliable and accurate. We all have mitochondria in our cells and thus, we all have MtDNA. In terms of genetic inheritance, we inherit our MtDNA from our mother and not from our father. This means that only females pass on their MtDNA to their children and males do not.

MtDNA testing is a type of relationship DNA test and can be done to verify whether siblings share the same biological mother. MtDNA undergoes very little changes and the incidence of mutation is also low.  MtDNA is passed on across generations relatively unchanged and thus is a great tool for establishing whether individuals have a common maternal ancestor and thus, share the same maternal line.

In cases of ancestry testing, genealogists also have particular interest in testing this gene.

MtDNA in criminal investigations

MtDNA testing can be a great way of identifying the remains of a person. In many cases, after a body has been left exposed to the elements for many years, it may be impossible to find nuclear DNA to help investigations. Nuclear DNA degrades quite easily if it is not stored properly. However, MtDNA can still be found in places like bone and hair. Even hair that has fallen off the body, or stuck to a murder weapon, and moreover, even a singly hair is enough for extracting MtDNA in such cases.

The MtDNA from the dead person can be compared to an alleged female relative to see if there is a match in an MtDNA test.

In cases of rape the assailant is likely to have left a hair on the body of his victim and this hair can be used to link the perpetrator to the victim (one of the reason why police discourage victims of rape from cleaning themselves after).

Find your origins with MtDNA

Do you Share the same Maternal Line? Do a Maternal Lineage Test. This test is designed to tell you about your ancient maternal roots. Click here to read more.