Can world's biggest shark help humans?

Whale sharks have caught the attention of medical researchers who are now studying the genome of the world’s largest fish.

“If you sequence any extreme — the biggest, the smallest, the fastest, the heaviest — all of these animals are interesting to biologists,” said Alistair Dove, director of research and conservation at the Georgia Aquarium, the only facility in North America to house live whale sharks. “They provide sort of the goal posts on where biology of this animal can occur. And so this is a terrific species to study because it’s so much bigger than all the others.”

Dove collaborated with Tim Read, a professor of infectious diseases at Emory University School of Medicine, to sequence the whale shark genome.

The researchers hope their ongoing analysis of whale shark genetics will lead to a better understanding of the threatened species and, perhaps, humans as well.

“Sharks are the first group of vertebrates to have antibodies in their blood to specific diseases,” Dove said. “So, if we want to understand where our own immune systems come from and how we come to have this ability to fight off the flu or other diseases, looking in the DNA of sharks is a great place.”

Read added that the research could also lead to a better understanding of autoimmune diseases in humans (such as rheumatoid arthritis, multiple sclerosis and lupus).

“Ideally you want to target invading microorganisms and avoid self targets,” Read said. “We’re going to see how the whale sharks may have solved that problem.”

Although whale sharks grow as long as 40 feet, they feed on tiny organisms, such as plankton, and pose no threat to humans. For an extra fee, visitors at the Georgia Aquarium can swim with the popular Atlanta attraction’s four whale sharks.

“They’re really indifferent to the presence of people, and essentially it’s the same when you see them in their natural setting out in the ocean,” Dove said. “They’re the largest fish in the world. They really don’t have a lot of natural predators. So, we represent very little threat to them at all.”

Humans may even prove helpful to whale sharks as they learn more about these gentle giants.

“They’re extremely mysterious,” Read said. “We know so little about the ecology of whale sharks in the wild. And actually one of the aspects of this work I’m particularly interested in, as well as immunology, is the conservation genomics — using the genome sequencing to understand what is the population of the whale sharks and what are the differences between whale shark populations in different (parts) of the world."