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The Great White Shark is not only a formidable predator, it also has an unusual resistance to cancer and a remarkable ability to heal wounds quickly, a team of scientists discovered after sequencing the genome of the sea creature to the fullest.
This discovery gives biologists a first glimpse of the shark's exceptional longevity – over 70 years old – and could also be used by medical researchers to prevent cancer, treat age-related ailments and heal wounds at home. the man, the researchers said.
"We believe that these evolutionary features can contribute to the long lifespan of white sharks and their bulky bodies, and could even contribute to the long-standing success of sharks as one of the oldest vertebrate lineages on Earth, "said Salvador Jorgensen, a senior official. researcher at the Monterey Bay Aquarium and co-author of the study. "Sharks have thrived for about 500 million years, longer than almost every vertebrate on the planet."
The findings, published February 19 in the journal Proceedings of the National Academy of Sciences, represent a breakthrough for scientists studying the adaptations of evolution in the marine environment. The unique genes for blood clotting and protection against cancer in white sharks have also been found in whale sharks, dispelling a long-held view among biologists that larger animals than humans are more likely to Cancer.
The research team, made up of scientists from California State University (Monterey Bay) and several other shark research centers and specialized veterinary centers in the United States and around the world, used blood, skin and white shark muscles off the coast of California to identify the active genes of creature DNAs.
Jorgensen explained that the idea was to identify the genes that had evolved, essentially the natural cellular selection. They have discovered many genes associated with stem cell maintenance and DNA repair, a type they associate with "genome stability" because they are specifically related to the fight against cancer. sickness and damage repair.
According to the study, the opposite phenomenon, the instability of the genome, predisposes humans to many cancers and age-related diseases.
"We find that nature has developed smart strategies to maintain genome stability in these large and long-lived sharks," said Mahmood Shivji, director of the Shark Research Center of the Nova Southeastern Save Our Seas Foundation. University, Florida, and one of the leading authors of the study, which also compared large white genes to other animals, including whale sharks and humans.
In addition to having more healing properties, scientists were surprised to discover that the genome of the great white had one and a half times the size of the human genetic code, probably because of all the molecular adaptations.
It is not known if white sharks do have cancer, but they heal wounds very quickly, even serious. The restoration pathways found in sharks could revolutionize medical science, said Shivji, who led the study with Michael Stanhope of the College of Veterinary Medicine at Cornell University.
Great White shark
Source: Shark Research Institute
"We still have a lot to learn from these wonders of evolution," Shivji said, "including potentially useful information for fighting cancer and age-related diseases and improving treatments for the healing of wounds in humans, while discovering how these animals do it. "
White sharks, known scientifically as Carcharodon carcharias, can live at least 73 years, reach 20 feet in length and weigh up to 7,000 pounds, making them one of the largest predatory fishes in the world.
Sharks, which have long scared Bay Area surfers, abalone divers and swimmers, live worldwide in cold, coastal waters and are known to dive to a maximum depth of 4,000 feet. They have a developed sense of smell and sight and an innate ability to detect changes in water pressure, which helps them find prey.
The genetic characteristics of sharks are important, said Jorgensen, because the population of large whites, especially along the west coast, remains relatively small compared to their historical numbers. Less than 350 adults were counted off the coast a few years ago, but reported sightings and encounters have recently increased, particularly along the central coast and southern California.
This is not the first genetic study on sharks that has given striking results. A historic report from Stanford University in 2009 determined that west coast sharks, known as white sharks from the northeastern Pacific, are genetically unique compared to other great whites in the world.
Local sharks, which feed primarily on elephant seals, sea lions and sea otters, are derived from a relatively small number of South Pacific sharks between Australia and the United States. New Zealand in the late Pleistocene, about 200,000 years ago, and have not mixed with other populations since then, revealed the Stanford study.
Carnivores with stubborn teeth are known to spend their winters in a deep spot near Hawaii near Hawaii, which scientists have dubbed the White Shark Cafe. From
August, they return to the Farallon Islands, where they feed until October. Some of them have been documented entering the San Francisco Bay Area.
The area they travel from Monterey Bay to the Farallon Islands, via Bodega Head, has been known for years as the Red Triangle, a scary name that many marine biologists avoid fleeing because it reinforces what they consider it a false impression – this Whites are bloodthirsty killing machines.
Experts claim that attacks on humans are rare and usually result from the fact that a shark takes for a sea lion a surfer or abalone diver. The only reported death in the Bay Area occurred in 1959, when a swimmer was attacked off Baker Beach in San Francisco.
The researchers said their discoveries are just the tip of the iceberg of what they expect to learn about white sharks during their studies.
Peter Fimrite is a staff writer for the San Francisco Chronicle. Email: [email protected]. Twitter: @pfimrite
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