A hypervariable region (HVR) is a location within nuclear DNA or the D-loop of mitochondrial DNA in which base pairs of

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecu ...

s repeat (in the case of nuclear DNA) or have substitutions (in the case of mitochondrial DNA). Changes or repeats in the hypervariable region are highly polymorphic.

Mitochondrial

There are two MITOCHONDRIAL 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. In the revised

Cambridge Reference Sequence The Cambridge Reference Sequence (CRS) for human mitochondrial DNA was first announced in 1981. A group led by Fred Sanger at the University of Cambridge had sequenced the mitochondrial genome of one woman of European descent during the 1970s, ...

of the human mitogenome, the most variable sites of HVR1 are numbered 16024-16383 (this subsequence is called HVR-I), and the most variable sites of HVR2 are numbered 57-372 (''i.e.,'' HVR-II) and 438-574 (''i.e.,'' HVR-III).''PhyloTree mt''
"Annotated mtDNA reference sequences: revised Cambridge Reference Sequence (rCRS)"
Retrieved on 4 February 2016. In some bony fishes, for example certain Protacanthopterygii and Gadidae, the mitochondrial control region evolves remarkably slowly. Even functional mitochondrial

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

s accumulate mutations faster and more freely. It is not known whether such hypovariable control regions are more widespread. In the Ayu (''Plecoglossus altivelis''), an

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea ...

n protacanthopterygian, control region mutation rate is not markedly lowered, but sequence differences between subspecies are far lower in the control region than elsewhere. This phenomenon completely defies explanation at present.Takeshima, Hirohiko; Iguchi, Kei-ichiro & Nishida, Mutsumi (2005): Unexpected Ceiling of Genetic Differentiation in the Control Region of the Mitochondrial DNA between Different Subspecies of the Ayu ''Plecoglossus altivelis''. '' Zool. Sci.'' 22(4): 401–410. (HTML abstract)

Antibodies

In antibodies, hypervariable regions form the antigen-binding site and are found on both

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...

and heavy chains. They also contribute to the specificity of each antibody. In a

variable domain An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

, the 3 H_V segments of each heavy or light chain fold together at the N-terminus to form an antigen binding pocket.

References

External links

* {{MeshName, Hypervariable+region
DNA: Forensic and Legal Applications, Explanation of Hypervariable Regions
Genetic genealogy Genetic engineering Antibodies

Mitochondrial

Antibodies

See also

References

External links