AUG 13, 2018 07:53 AM PDT

Insight Into the Origins of Junk DNA - From Koalas

WRITTEN BY: Carmen Leitch

The human genome is made up of four nucleotide bases: A, T, G, and C, that are arranged to form genes. However, aside from genes, there is a lot of other stuff in the genome including long strands of repetitive sequences that don’t have any readily apparent function. While the research that focused on those regions has revealed some things about their purpose, much is still unknown. Incredibly, koalas might be able to help scientists reveal some of the secrets of these so-called ‘junk’ sequences. Koalas often carry an infection that may explain how viruses impacted the genetic material of many different species was impacted.

Led by Professor and Virologist Paul Young, the Head of UQ's School of Chemistry and Molecular Biosciences, scientists have studied a koala retrovirus. Retroviruses can actually work their way into the genome of their host. 

"Retroviruses insert their genome into their host's chromosome, from where they make more copies of themselves," Young explained. "Some can also infect what are known as germline cells, which alters the host genetic code and that of all their descendants."

We know that the human genome has been altered by retroviruses for more than five million years, making it hard to study the first changes they made. Koalas, however, are undergoing more recent alterations.

"About a decade ago, we discovered that the wild koala population was being invaded by a retrovirus," said Young. "This isn't great news for the koala, but it has provided us with an opportunity to study what's happening to these retroviral genomes early in their association with a new host."

Koala / Credit: Carmen Leitch

Young noted that retroviruses could potentially replicate endlessly, which would eventually spell disaster for a species. But usually, the viruses eventually cease to cause disease and instead, confer new functions on an organism or turn inert, potentially as junk DNA. "Until now, scientists could only guess at why and how this happened," Young noted.

It would be very intriguing to see a retrovirus at work, said Professor Joanne Meers of UQ. "Because the koala retrovirus is still relatively young - less than 50,000 years old - and not yet 'fixed' in a certain location within the koala genome, scientists can monitor this early engagement between a retrovirus and its host."

"This means that the koala, a species not usually associated with biomedical breakthroughs, is providing key insights into a process that has shaped eight per cent of the human genome, and will likely show us what happened millions of years ago when retroviruses first invaded the human genome,” added Professor Alex Greenwood of the Leibniz Institute for Zoo and Wildlife Research in Berlin.


Sources: AAAS/Eurekalert! via University of Queensland, PNAS

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 02, 2018
Drug Discovery
OCT 02, 2018
Mycobacterial Lung Disease, FDA Approves New Drug
New drug seeking to treat antibiotic-resistant lung disease has just been approved by the U.S. Food and Drug Administration. The drug is called ‘Arik...
NOV 03, 2018
Microbiology
NOV 03, 2018
Potential new Tuberculosis Treatment Found in Dirt
The pathogen that causes TB has been able to evolve, and often, the typical therapeutic for the illness does not work....
NOV 05, 2018
Microbiology
NOV 05, 2018
Potential Antidote to Botulism is Found
A microbe called Clostridium botulinum and sometimes two other strains of Clostridium bacteria can make a toxic chemical called botulism....
NOV 15, 2018
Videos
NOV 15, 2018
A Season of Outbreaks
In a few different places around the world, people are facing disease outbreaks due to pathogenic microbes....
NOV 25, 2018
Videos
NOV 25, 2018
Ongoing Ebola Outbreak in DRC Becomes Country's Worst Ever
On August 1, 2018, an Ebola outbreak was declared in the Democratic Republic of the Congo, which is still ongoing....
NOV 26, 2018
Health & Medicine
NOV 26, 2018
Nontuberculous Mycobacterial Infections in Tattoos
Contracting an infection when getting a tattoo is always a major concern. Consumers should be aware of the risk of developing infections with bloodborne pa...
Loading Comments...