The culprit responsible for a shark bite that took place a quarter of a century ago was discovered after a piece of a shark’s tooth was removed from the victim 25 years later.
A DNA test of the tooth, conducted by scientists at the Florida Museum of Natural History, found that a blacktip shark was to blame for an incident that took place in 1994.
The victim, Jeff Weakley, was bitten while surfing off the coast of Flagler Beach, Florida. He had suspected that it was a blacktip that was responsible.
“I was very excited to determine the identity of the shark because I’d always been curious,” said Weakley. “I was also a little bit hesitant to send the tooth in because for a minute I thought they would come back and tell me I’d been bitten by a mackerel or a houndfish—something really humiliating.”
Weakley, who now works as the editor for Florida Sportsman Magazine, had planned on turning the tooth into a jewelry pendant before donating it to be tested. Nearly 25 years later, he has not let the incident keep him away from the water.
“I certainly don’t have a hatred of sharks or any feeling of vindictiveness toward them. They’re part of our natural world,” he said.
Gavin Naylor, director of the shark research program, was surprised that viable DNA was left in the tooth fragment to analyze after 24 years in Weakley’s foot where it would have been attacked by his immune system.
Along with laboratory manager Lei Yang, the tooth was cleaned of contaminants, the tooth enamel was removed and pulp tissue was scraped from the tooth’s cavity. DNA was then extracted from the tissue, purified and broke into small pieces. Molecular “bookends” were added on either side of each piece. which made a genomic “library” out of the DNA. Yang compared the target sequences against two databases of shark and ray genetic information to determine Weakley had been bitten by a blacktip.
“It was a mystery waiting for us to uncover,” Yang said.