The Science
There are three possible areas in our mtDNA that can be tested:
- HVRI Testing: this region is usually sufficient to determine a person's haplogroup
- HVRII and HVRIII Testing: these two regions can provide more detail if HVSI testing is not sufficient to determine connection to a haplogroup; it could also further refine a haplogroup into sub-groups, also called sub-clades
Our testing includes all three areas, giving you the best coverage of genetic markers for the highest probability of determining your haplogroup.
The Science behind your Maternal Lineage (mtDNA) DNA Test
What makes mitochondrial DNA special? Several characteristics of mitochondrial DNA distinguish it from the rest of your cells' DNA, called nuclear DNA.
Results of a maternal lineage test are expressed in terms of haplogroups—genetic groups of people who share the same set of DNA markers and can be traced to a certain geographic area that they settled at a particular point in human history.
Mitochondrial DNA is:
- Found in the cytoplasm, outside the nucleus
- Only passed through the mother. During fertilization, only nuclear DNA from the sperm enters the cell; thus the father does not make any contribution to the mitochondrial DNA
- Abundant in number. While your nuclear chromosomes are only found in two copies per cell, one from your mother and one from your father, mtDNA is found much more abundantly—anywhere between hundreds to thousands of copies per cell
- Small and circular. While nuclear DNA is made up of much longer strands of DNA that are tightly coiled into chromosomes, mitochondrial DNA is found as a small, circular chromosome
Mitochondrial DNA codes for proteins that are involved in cellular respiration. In addition, certain regions of the mtDNA are useful for ancestry research. These regions are called hypervariable regions (HVR).
HVRs are the site where the most mutations occur in mtDNA. On average, one letter in the sequence of mtDNA changes every 1,500 years. This change is then passed on to succeeding generations. The changes in an individual's mtDNA comprise his or her haplotype—the mitochondrial DNA profile—that allows scientists to assign a person to his or her haplogroup, a group of people with similar haplotypes. The haplogroup is associated with a historical and geographical origin.
