I'm pretty sure TLT has got it all over them. :-)
Researchers mapping the genome of great white sharks have discovered results that could have implications in fighting cancer and age-related diseases in the future.
Like the fictional Marvel comic character of Wolverine, it turns out white sharks have real-world genetic adaptations that make them incredibly efficient at wound healing and even the prevention of the formation of deadly cancers.
The research project’s study of white shark and whale shark genomes are explained in a paper released this week in the Proceedings of the National Academy of Sciences, USA.
Mahmood Shivji, director of the Save Our Seas Shark Research Centre and the Guy Harvey Research Institute at Nova Southeastern University in Florida, was one of the co-authors of the paper. He also gave large credit to co-author Michael Stanhope at Cornell University.
“I want to emphasize, we’ve only just scratched the surface of this genome,” Shivji said in a telephone interview on Friday. “The first step, of course is getting the genome ... and then looking in more detail at what ... genes are (there) and what they’re doing.”
The scientists used samples from two white sharks, one caught by a fisherman off Delaware in the Atlantic and another in the Pacific. In a process that took four years of research and analysis, the team mapped the sharks’ genome revealing a massive amount of data.
First, the white shark’s is a huge genome, Shivji said, equating to about 1.5 times the size of the human genome.
“The human genome is about three billion base pairs. The white shark genome is 4.63 billion base pairs. So a lot bigger.”
Almost 60 per cent of it is made up of repeated gene sequences. About 30 per cent of those are made up of a type of DNA sequence called “LINEs,” or “jumping genes.” These can make copies of themselves that can jump around and insert themselves randomly into the genome.
One would think this could give rise to errors, leading to unstable DNA, which can lead to diseases like malignant cancer. But at the same time many of the genes the team observed are involved in the critical process of maintenance of genome stability, like DNA repair genes, tumour suppressor genes and those involved in the process that tells cells when they should die.
Those genes were enriched, Shivji said. They had also undergone small changes in their sequence through evolutionary positive selection.
“These are advantageous mutations that have occurred in these genes, the genome’s stability genes, and have been kept around,” he said.
“That was, I’d call it, a Eureka moment for us.”
Many of the genes that were enriched and had undergone these advantageous sequence changes were also involved in key wound healing processes.
The next step would be to do studies of the genes’ effects in human and mouse cell line model systems in a lab to see how they react to potential cancer-causing mutations.
“Is that going to lead to some magic pill?” Shivji asked. “Who knows? We don’t know.”
But if it works in cell lines, further research will be warranted.
They didn’t map the genes of other species but the Guy Harvey Research Institute does have a tracking project. They’ve tagged and tracked mako, ocean white-tips, tiger and whale sharks in the Atlantic, including into Nova Scotia waters. The tracking data can be seen at ghritracking.org.
Shivji wanted to stress that they don’t want people to think that eating sharks is a cure for cancer.
“There’s a lot of cool stuff that we’re going to learn from these animals," he said, another reason why it's essential to conserve them.
“Thinking that eating sharks is going to cure cancer is about as silly as thinking that eating sharks is going to make you swim faster or breathe underwater better. It doesn’t make any sense.”
Fred Whoriskey, a shark researcher with Dalhousie University’s Ocean Tracking Network, was not surprised to hear about the results of the study, primarily because the animals have been around for hundreds of millions of years.
“They have been solving all sorts of problems over those hundreds of millions of years and you would expect their genome to have gotten to address a lot of these kinds of issues,” Whoriskey said.
“So it is a very fruitful and intelligent direction to go to conduct research and I was pleased to see that there were some hopeful avenues in this study that came out that suggested places where we may be able to go to address some pretty significant health problems in humans.”