Mitochondrial DNA or MtDNA is the DNA found in cell mitochondria and is very useful to DNA testing companies; the explanation for importance of MtDNA testing in relationship DNA testing will be given later in the article. DNA testing is today highly reliable and accurate and can clarify most doubts regarding genetic relationships between people.
The basics of the human cell and DNA
Cells contain what are called organelles; organelles are parts of the cell which are suspended in a semi-liquid matrix known as the cell cytoplasm. When you do a standard paternity DNA test, an avuncular DNA test or a twin zygosity DNA test, the DNA samples you send in containing DNA from the cell nucleus. The cell nucleus is the ‘brain’ of the cell. On the other hand, mitochondria (singular: mitochondrion) are different cell organelles responsible for providing energy to the cell and contain a special type of DNA known as mitochondrial DNA or MtDNA for short.
How is MtDNA inherited and how is it used in DNA testing?
In relationship to DNA testing, inheritance patterns of MtDNA are very important. MtDNA is present in both males and females; however, it is only females that pass it on to their offspring. In genetic testing an MtDNA test is a relationship DNA test which can reliably establish whether people share a common maternal line.
The test may be used to establish whether two siblings share the same biological mother or simply to tell you whether there is a common maternal ancestor. Thus, this MtDNA is a very valuable tool for genealogists to draw up family trees and the genetic origins of people.
Advantages of MtDNA
MtDNA has many advantages over nuclear DNA. Here are some of the most important ones:
- Mitochondria are strong organelles in terms of their structure. This means that MtDNA in them is protected and it does not degrade easily. This is unlike nuclear DNA which is degraded by environmental factors such as heat and also time and thus, may sometimes be useless for DNA testing.
- The human cell contains only one nucleus. In this nucleus we find the DNA we use in most DNA tests. Conversely, the human cell contains thousands of mitochondria. This means that even very small samples will contain enough MtDNA for testing.
- MtDNA is found in bones and other parts of the body where we sometimes do not find nuclear DNA
Other uses of MtDNA testing
In cases where a crime has been committed and there has been excessive degradation of Nuclear DNA, it is likely that investigators can still find enough MtDNA to carry out genetic testing to identify the victim. Naturally shed hairs, even a single hair, and hair shafts can be potential sources of MtDNA. If the corpse cannot be identified, then samples of MtDNA can be taken and compared to a living relative to see if the two people are related though the same maternal line.
Lineage testing for males
The Y Chromosome test can give you an accurate answer to whether two male persons are connected through the male bloodline. The Y-Chromosome test is an extremely conclusive test that is able to determine if a direct line exists in between two men. Here is some more information about Y chromosome lineage testing.