Hypervariable Region (HV1, HV2)
Definition
Two segments within the mitochondrial D-loop that accumulate sequence variation faster than the coding mitochondrial genome. HV1 spans positions 16024-16365; HV2 spans positions 73-340. Both are routinely sequenced in forensic casework.
- Location
- Mitochondrial D-loop control region
- HV1 range
- Positions 16024 to 16365
- HV2 range
- Positions 73 to 340
- Use
- Routinely sequenced regions in forensic mtDNA casework
Common questions
Why does mtDNA testing focus on HV1 and HV2 rather than the whole mitochondrial genome?+
These non-coding control-region segments accumulate mutations faster than the coding genome, giving useful discrimination between maternal lineages while keeping sequencing effort limited to a manageable target, though whole mitogenome sequencing is increasingly used for extra resolution.
How is an HV1/HV2 sequence result compared between a questioned and reference sample?+
Both sequences are aligned to the revised Cambridge Reference Sequence and reported as differences from it; a match supports the samples sharing a maternal lineage, but because mtDNA does not recombine, a match cannot individualize the way nuclear STR profiling can.
Related terms
- AFDIL
- Armed Forces DNA Identification Laboratory, at Dover Air Force Base, Delaware. The US military's central identification laboratory, responsible for mtDNA-based identification of...
- EMPOP
- EMPOP mtDNA Population Database, maintained at the Institute of Legal Medicine, Innsbruck, Austria. Contains over 50,000 curated mtDNA sequences and uses phylogenetic...
- Heteroplasmy
- The co-existence of two or more mitochondrial DNA sequence variants within a single individual, arising from somatic mutation or incomplete segregation. Length...
- rCRS
- The revised Cambridge Reference Sequence (GenBank accession NC_012920), the standard reference for human mitochondrial DNA. All mtDNA variant positions in forensic and...
- RSRS
- Reconstructed Sapiens Reference Sequence (2012). A phylogenetically derived ancestral human mtDNA sequence used in academic population genetics but not in forensic casework...