Hypervariable region

A hypervariable region (HVR) is a location within nuclear DNA or the D-loop of mitochondrial DNA in which base pairs of nucleotides repeat. Repeats in the hypervariable region are highly polymorphic.

Genetic genealogy
There are two hypervariable regions used in human mitochondrial genealogical DNA testing. HVR1 is considered a "low resolution" region and HVR2 is considered a "high resolution" region. Getting HVR1 and HVR2 DNA tests can help determine one's haplogroup.

HVR1 locations are numbered 16001-16568. HVR2 locations are numbered 001-574.