Featured Research

from universities, journals, and other organizations

Unexpected viral 'fossils' found in vertebrate genomes

Date:
July 30, 2010
Source:
Public Library of Science
Summary:
Over millions of years, retroviruses, which insert their genetic material into the host genome as part of their replication, have left behind bits of their genetic material in vertebrate genomes. In a recent study, a team of researchers found that human and other vertebrate genomes also contain many ancient sequences from Ebola/Marburgviruses and Bornaviruses -- two deadly virus families.

Colorized negative stained transmission electron micrograph (TEM) depicts a number of Marburg virus virions.
Credit: CDC/Frederick Murphy

Over millions of years, retroviruses, which insert their genetic material into the host genome as part of their replication, have left behind bits of their genetic material in vertebrate genomes. In a recent study, published July 29 in the open-access journal PLoS Pathogens, a team of researchers have now found that human and other vertebrate genomes also contain many ancient sequences from Ebola/Marburgviruses and Bornaviruses -- two deadly virus families.

Because neither virus family inserts their genetic material into the host genome during replication, as retroviruses do, the discovery was all the more unexpected.

"This was a surprise for us," says author Anna Marie Skalka, Ph.D., Director Emerita of the Institute for Cancer Research at Fox Chase Cancer. "It says that the source of our genetic material is considerably wider than we thought. It includes our own genes and unexpected viral genes as well."

The team, which included lead author Vladimir A. Belyi, Ph.D., and co-author Arnold J. Levine, Ph.D., both at the Institute for Advanced Study in Princeton, compared 5,666 viral genes from all known non-retroviral families with single-stranded RNA genomes to the genomes of 48 vertebrate species, including humans. In doing so, they uncovered 80 separate viral sequence integrations into 19 different vertebrate species. Interestingly, nearly all of the viral sequences come from ancient relatives of just two viral families, the Ebola/Marburgviruses and Bornaviruses, both of which cause hemorrhagic fevers and neurological disease.

"These viruses are RNA viruses," Skalka says. "They replicate their RNA and are not known to make any DNA. And they have no known mechanism for getting their genetic material integrated into the DNA of the host genome. Indeed, some of them don't even enter the nucleus when they replicate."

That the sequences, some of which may have been integrated into the genomes more than 40 million years ago, have been largely conserved over evolutionary time suggests that they give the host a selective advantage, perhaps protecting them from future infections by viruses from those families. The study shows that integration of the ancient viral sequences was probably mediated by movable elements, LINEs, which are abundant in mammalian genomes.

"In a way, one might even think of these integrations as genomic vaccinations," says Skalka.

Demonstrating conclusively that the viral sequences have some biological function will take additional work. However, the team has noted that expression of some of these viral open reading frames has been detected in human tissues, which supports the possibility that they are biologically active in host species.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Belyi VA, Levine AJ, Skalka AM. Unexpected Inheritance: Multiple Integrations of Ancient Bornavirus and Ebolavirus/Marburgvirus Sequences in Vertebrate Genomes. PLoS Pathogens, 2010; 6 (7): e1001030 DOI: 10.1371/journal.ppat.1001030

Cite This Page:

Public Library of Science. "Unexpected viral 'fossils' found in vertebrate genomes." ScienceDaily. ScienceDaily, 30 July 2010. <www.sciencedaily.com/releases/2010/07/100729172330.htm>.
Public Library of Science. (2010, July 30). Unexpected viral 'fossils' found in vertebrate genomes. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2010/07/100729172330.htm
Public Library of Science. "Unexpected viral 'fossils' found in vertebrate genomes." ScienceDaily. www.sciencedaily.com/releases/2010/07/100729172330.htm (accessed September 15, 2014).

Share This



More Plants & Animals News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) — New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) — A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. Video provided by Newsy
Powered by NewsLook.com
'Magic Mushrooms' Could Help Smokers Quit

'Magic Mushrooms' Could Help Smokers Quit

Newsy (Sep. 11, 2014) — In a small study, researchers found that the majority of long-time smokers quit after taking psilocybin pills and undergoing therapy sessions. Video provided by Newsy
Powered by NewsLook.com
Spinosaurus Could Be First Semi-Aquatic Dinosaur

Spinosaurus Could Be First Semi-Aquatic Dinosaur

Newsy (Sep. 11, 2014) — New research has shown that the Spinosaurus, the largest carnivorous dinosaur, might have been just as well suited for life in the water as on land. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins