Navigation Links
Retrovirus struck ancestors of chimpanzees and gorillas millions of years ago, but did not affect ancestral humans

The ancestors of chimpanzees and gorillas were infected with a deadly retrovirus about three to four million years ago, but there is no evidence it infected ancestors of modern-day humans, according to research by genome scientists. The virus struck after humans had split off the evolutionary tree from primates, researchers said. The infection may have played a role in the evolution of such great apes as chimps and gorillas. The research appears in the April issue of the journal Public Library of Science-Biology, which is available online on March 1.

Researchers studying portions of the genome containing 'retroelements,' also known as junk DNA, found many copies of a gene sequence in the chimp and gorilla genome that didn't appear anywhere in the human genome. They translated that genome sequence into its corresponding protein, and discovered that it was the remnant of a retrovirus, a type of virus that copies its genetic information into the host's genome. Evidence suggests that the 'retroelement' originated from an external retrovirus that actively infected ape species in the past.

"The reason retroviruses are so deadly, at the genetic level, is that they have a tremendous potential to mess up a gene and interfere with its expression," explained Dr. Evan Eichler, UW associate professor of genome sciences and co-author of the study. "That can have negative effects. It's a double-whammy: the virus infected and possibly killed off some of the population, but also caused genetic errors in survivors. Those errors would have later eliminated more of the population."

The virus had invaded the genome in the germline -- in sperm or egg cells -- allowing the sequence to be passed on to future generations. In those animals in which the virus was taken up next to or inside a gene -- in the part of the genome that codes for the most important biological functions -- the virus had an even stronger effect.

What researchers don't understand is why t he virus affected the ancestors of chimps, gorillas, and Old World monkeys, but didn't affect the ancestors of humans or of Asian apes like orangutans and gibbons. The infections took place independently, and did not originate in a common ancestor of humans and apes. The event also took place between three and four million years ago, well after the separation of humans from apes. That split is estimated to have occurred five to seven million years ago. During that period, ancestral humans were likely to be living in the same area of Africa as great apes. African apes may have been susceptibile to the virus, or ancestral humans and Asian apes may have been resistant to it. Another possibility is that some early humans may have carried the virus, but eventually died off.

Researchers also don't know the impact the virus had on the primate species it did affect. They found many copies of the virus in the genomes of both species, but only a tiny fraction of those copies landed in or near a gene, where it would have the greatest impact. Other studies have shown that most retroviruses typically land near or within genes. This difference may mean the animals that had the virus taken up in or near a gene didn't survive long. Because of that natural selection, researchers believe that the virus may have had major impacts on the formation of the species we now call chimps and gorillas. The virus struck when each of the primate groups was still an incipient species with widely varying populations.

If the virus had killed off much of the population of both species, it may have created what evolutionary biologists call a population bottleneck. This much smaller group of surviving animals would then sort out most of its genetic variation in relatively fewer generations than would a larger group. This would lead to a higher probability of rare genetic variants becoming fixed in a short time. Before long, a genetically disparate population, possibly with wide variati ons in morphology, would have emerged, leading to today's chimps and gorillas.

The study's lead authors are Zhaoshi Jiang, a Ph.D. student in Eichler's lab at the UW, and Chris Yohn, a technician at Case Western Reserve University in Cleveland.


Source:University of Washington

Related biology news :

1. New technology shows our ancestors ate…everything!
2. Why we give: New study finds evidence of generosity among our early human ancestors
3. Protowings may have helped bird ancestors cover rough terrain
4. Mans earliest direct ancestors looked more apelike than previously believed
5. Poaching, logging, and outbreaks of Ebola threaten central African gorillas and chimpanzees
6. UAB researchers confirm HIV-1 originated in wild chimpanzees
7. Male chimpanzees prefer mating with old females
8. Road-crossing in chimpanzees: A risky business
9. Gene study shows three distinct groups of chimpanzees
10. Ebola outbreaks killing thousands of gorillas and chimpanzees
11. Female-led infanticide in wild chimpanzees
Post Your Comments:

(Date:6/22/2016)... LOS ANGELES , June 22, 2016 ... of identity management and verification solutions, has ... cutting edge software solutions for Visitor Management, ... ® provides products that add functional ... The partnership provides corporations and venues with ...
(Date:6/16/2016)... , June 16, 2016 ... size is expected to reach USD 1.83 billion ... Grand View Research, Inc. Technological proliferation and increasing ... applications are expected to drive the market growth. ... , The development of advanced multimodal ...
(Date:6/7/2016)... , June 7, 2016  Syngrafii Inc. and ... business relationship that includes integrating Syngrafii,s patented LongPen™ ... project. This collaboration will result in greater convenience ... credit union, while maintaining existing document workflow and ... ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , June 27, 2016 /PRNewswire/ - BIOREM Inc. (TSX-V: BRM) ... advised by its major shareholders, Clean Technology Fund I, ... United States based venture capital funds which ... Biorem (on a fully diluted, as converted basis), that ... of their entire equity holdings in Biorem to TUS ...
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , the leading ... the Clinical Reach Virtual Patient Encounter CONSULT module which enables both audio ... and clinical trial team. , Using the CONSULT module, patients and physicians can schedule ...
(Date:6/27/2016)... PHILADELPHIA , June 27, 2016  Liquid ... today announced the funding of a Sponsored Research ... study circulating tumor cells (CTCs) from cancer patients.  ... changes in CTC levels correlate with clinical outcomes ... therapies. These data will then be employed to ...
(Date:6/24/2016)... , June 24, 2016 Epic Sciences ... detects cancers susceptible to PARP inhibitors by targeting ... cells (CTCs). The new test has already been ... in multiple cancer types. Over 230 ... damage response pathways, including PARP, ATM, ATR, DNA-PK ...
Breaking Biology Technology: