Endogenous Retroviruses From Madagascar Mouse Lemurs Is Similar To Other Mammals

Among the many lemur species in Madagascar, the mouse lemur is one of the many endemic species that make up its distinctive biodiversity.

The viruses now exhibit characteristics similar to lemur genes and are referred to as endogenous retroviruses (ERVs).

The surprising relationship between some of the identified retroviruses and viruses found in other, very different mammals, like polar bears or domestic sheep, caught researchers off guard.

Retroviruses in Madagascar mouse lemurs similar to polar bears and domestic sheep

The group obtained blood samples from four different species of Malagasy mouse lemurs and screened those using high throughput sequencing for their analysis, as per ScienceDaily.

Three beta retrovirus sequences, two gamma retrovirus sequences, and two gamma retrovirus sequences were found in the genomes of the lemurs, which represent early infections of mouse lemur germlines.

Ever since, the virus DNA has been infused into the host genomes, rendering the viruses inactive and contagious.

The beta retroviruses contained additional surprises.

The first cloned sheep, Dolly, had to be put to sleep after contracting the dangerous retrovirus Jaagsiekte sheep retrovirus (JSRV), which also causes ERVs in domestic sheep.

JSRV is thought to be restricted to domestic sheep, goats, and their relatives. A genetically similar JSRV-like virus has been found in the genomes of mouse lemurs.

Indicating a complex pattern of viral host switching all around time the ancestors of lemurs colonized Madagascar, a large portion of the mouse lemur retroviral diversity observed is involved with non-primate viruses.

It will be easier to understand the convoluted background of retroviral transmission between many mammals with the help of further research on viral diversity.

Retroviruses are types of viruses that spread through the integration of their genetic material into the genome of a host cell.

The retrovirus can then be transmitted as an endogenous retrovirus and spread across a whole population as a component of the host genome if indeed the infected cell is a germ cell.

Endogenous retroviruses are now common in mammalian genomes and can occasionally account for sizable portions of said host genome as a result of repeated infections.

The majority of retrovirus integrations, however, are extremely old and already degraded, rendering them inactive and having had their initial impact on the host health diminished by evolution over millions of years.

Origin of retrovirus

At the turn of the century, two studies focused on neoplastic diseases in chickens and led to the discovery of retroviruses, as per NCBI.

The Danish medical-vet team of Vilhelm Ellermann and Oluf Bang demonstrated in 1908 that chicken leukosis, a type of lymphoma and leukemia, was brought on by a virus.

Peyton Rous at the Rockefeller Institute in New York reported that sarcoma in chickens being transmitted without cells in 1911.

The study of tumors caused by viruses eventually included mammalian species.

John Bittner established in 1936 that a milk-transmitted, filterable agent causes mouse mammary carcinoma, and Ludwik Gross reported in 1957 on successful attempts to pick a potent leukemia virus in mice by such a combination of inbreeding and early inoculation.

Numerous viruses that caused neoplastic disease in mice, cats, cattle, and monkeys were discovered over the course of the following two decades.

By the early 1930s, there had been reports of about 20 viral isolates that cause tumors that are histologically distinct, which was a significant increase in the number of virus-induced tumors in poultry.

New avian retroviruses continue to be discovered.