A gammaretrovirus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of the retroviridae family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

. Example species are the murine leukemia virus

Murine leukemia virus

The murine leukemia viruses are retroviruses named for their ability to cause cancer in murine hosts. Some MLVs may infect other vertebrates. MLVs include both exogenous and endogenous viruses...

 and the feline leukemia virus

Feline leukemia virus

Feline leukemia virus is a retrovirus that infects cats. FeLV can be transmitted between infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal’s immune system, the virus can be lethal...

.

Many endogenous retroviruses, closely related to exogenous gammaretroviruses, are present in the DNA of mammals (including humans), birds, reptiles and amphibians.

Many of the Gammaretroviruses share a conserved RNA structural element called a core encapsidation signal

Gammaretrovirus core encapsidation signal

The Gammaretrovirus core encapsidation signal is an RNA element known to be essential for stable dimerisation and efficient genome packaging during virus assembly. Dimerisation of the viral RNA genomes is proposed to act as an RNA conformational switch which exposes conserved UCUG elements and...

. XMRV is an example of a possibly human gammaretrovirus.http://www.nytimes.com/2009/10/21/opinion/21johnson.html?ref=global

External links

• Viralzone: Gammaretrovirus