Skip to content
Environment, National News Current Affairs

Sharks’ cancer secret also puts them at risk: study

Monash University 4 mins read

New international Monash University-led research has explained the reasons for and implications of low cancer rates in sharks, which until now have remained a decades long mystery.

In a world-first collaborative international study, co-led by Monash University’s Australian Regenerative Medicine Institute (ARMI), with researchers from Germany, Sweden and the USA, scientists have discovered that sharks possess the lowest level of mutation between generations of any vertebrate species (animals with a backbone) to date.

This low level of mutation may be the key to explaining why they are less likely to develop cancers. While this may sound like good news for sharks, it turns out to be a double-edged sword.

Mutations are critical as they generate genetic variability within populations, facilitating the ability to adapt to new conditions and enabling evolutionary change. With sharks evolving very slowly, this puts them at risk of being unable to withstand ecological pressures such as overfishing and habitat loss.

The research, published in Nature Communications, highlights the urgent need to prioritise preservation of the remaining genetic diversity of global shark populations.

The study established the first ‘laboratory’ shark model using the epaulette shark, a small species found north-east of Australia. This surprisingly resilient shark can walk for up to 30 metres on land using paddle shaped fins and survive without oxygen for up to two hours, attributes that made them an ideal candidate for a captive breeding program at ARMI.

“Our development of breeding and pair mating protocols for epaulette sharks enabled us, for the first time, to genetically evaluate the mutation rate within a shark pedigree,” explained ARMI Director of Research and co-senior author, Professor Peter Currie.

Using the newly established shark model, the international research team generated a high-quality reference genome, and re-sequenced the entire genome of parents and nine offspring to detect new mutations.

“We estimate a mutation rate of 7×10−10 per base pair of DNA, per generation in epaulette sharks, which is the lowest mutation rate recorded to date for any vertebrate species,” Professor Currie said.

“This suggests that sharks may have a lower capacity to survive a drastic fall in population numbers compared to other species. Until now, sharks had not been included in mutation rate research of vertebrates despite the important role they played in a diverse range of marine ecosystems. 

“It can also explain low cancer rates in shark species, as the mutation rates that generate cancers would be expected to be low in sharks, given they are linked to the inherited mutation rate

“We therefore hope that this study will provide the evidence required to end the pointless harvesting of shark species for the production of baseless dietary supplements that give false hope to cancer sufferers. 

"The next step for our research is to understand what is unique about the biology of sharks that leads to this low rate of mutation, knowledge that may lead to an ability to slow mutation rates in our own tissues and lower cancer incidence.

Up to 72 million sharks are killed annually by the fin trade, with many targeted species facing the threat of extinction. Many more sharks are harvested for cartilage extracts used in dietary supplements for cancer treatments, and sharks are often caught inadvertently in fisheries directed at other species.

Joint first author Dr Frank Tulenko, an ARMI research fellow, said mutations were fundamental to evolution because they generated variability within populations, enabling evolutionary change.    

“The mutation rate is a crucial parameter for many calculations and predictive modelling in the fields of ecology and evolution, genetics and genomics,” Dr Tulenko said. “The rate of mutation provides an indication of a species’ ability to generate diversity, with a low rate of intergenerational mutations indicative of a reduced ability to respond to a sudden drop in population numbers.”

Professor Currie said the extremely low mutation rates could hamper efforts to restore shark populations and genetic diversity. 

“We know that sharks are particularly sensitive to unsustainable fishing practices and rapid changes in habitats,” Professor Currie said. “Now we also know that sharks evolve slowly, which means they are less able to counteract the mounting ecological threats they face.

“As sharks play fundamental roles in a diverse range of marine ecosystems, it is critical that we support conservation efforts to preserve the genetic variation within shark populations and to protect shark species more broadly.”

This study was jointly led by:
Team Lead Australia, Professor Peter Currie, Australian Regenerative Medicine Institute, Monash University. Contact: peter.currie@monash.edu
Team Lead Germany: Professor Manfred Schartl, University of Würzburg.                  
Contact: phch1@biozentrum.uni-wuerzburg.de  
Team Lead Sweden: Professor Leif Andersson, Uppsala University.
Contact: leif.andersson@imbim.uu.se  
Team Lead USA, Professor Shawn Burgess, National Institutes of Health.
Contact: burgess@mail.nih.gov   

About The Australian Regenerative Medicine Institute at Monash University
The Australian Regenerative Medicine Institute is one of the largest regenerative medicine and stem cell research organisations globally and Australia’s only research institute specialising in regeneration and stem cells. Located on the Clayton campus of Monash University, researchers at ARMI focus on understanding the basic mechanisms of the regenerative process, aiming to eventually enable doctors to prevent, halt and reverse damage to vital organs due to disease, injury or genetic conditions. Website: https://www.armi.org.au/

For media enquiries please contact:

Monash University
Cheryl Critchley - Communications Manager (medical)
E: cheryl.critchley@monash.edu
T: +61 (0) 418 312 596

For more Monash media stories, visit our news and events site

For general media enquiries please contact:
Monash Media
E: media@monash.edu
T: +61 (0) 3 9903 4840

 

***ENDS***

More from this category

  • Environment
  • 05/03/2024
  • 08:16
Climate Council

Climate pollution is “cooking” the Reef with law reform needed

FOR IMMEDIATE RELEASE DATE TUESDAY 5 MARCH THE CLIMATE COUNCIL is sounding the alarm on a severe bleaching event unfolding across the Great Barrier Reef, with new vision showing the damage that stretches more than 1100 kilometres from Lizard Island to the Keppel Islands.Marine heatwaves are bleaching swathes of the Southern Great Barrier reef white, which have brought direct observers to tears. With an ominous marine forecast for the coming weeks, authorities could declare another mass bleaching event. The Reef, a cherished global icon and home to diverse marine life and a cornerstone of Australian natural heritage, faces repeated and…

  • Environment, Science
  • 05/03/2024
  • 08:00
Banksia Foundation

35th National Banksia Sustainability Award finalists showcase new frontiers in sustainability

From reducing loved pets’ carbon paw print to developing a virtual powerplant, the finalists announced today for the 35th National Banksia Sustainability Awards demonstrate the full scope and talent of environmental and social impact projects in Australia. Revealing the short list, Banksia Foundation CEO Graz van Egmond praised finalists for their commitment to sustainability and social impact, and for the wide range of entries. “Across the categories this year, we have seen an incredible diversity of entries and finalists, from sole traders to large enterprises, all thinking and working creatively and effectively to combatting climate change and inequity.” “At a…

  • Contains:
  • Environment, Science
  • 05/03/2024
  • 07:08
CMC

“MOST RESEARCH SITES ARE BLEACHED DOWN TO SIX METRES” The Southern Great Barrier Reef has been cooked by an “underwater bushfire”, and the marine heatwave is causing coral reefs to bleach across the entire ecosystem.

There have been four mass coral bleaching events on the Great Barrier Reef in the past eight years - scientists tell us this kind of stress means species don’t have enough time to recover, fundamentally changing the reef and its biodiversity. The current marine heatwaves have caused swathes of the Southern Great Barrier reef to bleach, and the ominous marine forecasts for the coming weeks has almost the entire ecosystem in the highest alert level for another mass bleaching event. Climate pollution from burning fossil fuels is warming our planet, and with over 90% of atmospheric heat being absorbed by…

Media Outreach made fast, easy, simple.

Feature your press release on Medianet's News Hub every time you distribute with Medianet. Pay per release or save with a subscription.