News

'Virgin birth' draws fish world to ECCO aquarium

Kortney Clark points to Epa, who seems to have produced parthenogenetic offspring.

By Bill Moss, Published: August 28, 2015

Last week, when ECCO founder and executive director BJ Ramer was away, Kortney Clark was making the rounds of the 400-gallon fish tank at the Team ECCO Ocean Center & Aquarium on Main Street.

Epa, a 4-year-old Bamboo shark, had been especially prolific laying eggs. She was up to 38. Kortney noticed something very unusual about one of them. A tiny baby shark, called a pup, was swimming inside the casing.
“I called (coworker) Mary Lynn (Marks) and said, ‘Come over here. I think I’m seeing things.’” What they were seeing was real — likely a rare occurrence of a parthenogenetic birth. Kortney called Ramer.
“She was jumping and down, calling everybody (to ask) ‘What do we do?’” Kortney said. “I figured she’d be on a plane back here.”
Although Ramer finished her vacation, she immediately got on the phone with aquarium sources around the country to gather information and get advice.
“Parthenogenesis, from the Greek meaning ‘virgin birth’ is an odd quirk of embryonic development that allows female animals of some species to give rise to offspring without a male genetic contribution — usually by a doubling of the egg genome to generate a new embryo with the proper number of chromosomes,” Jennifer V. Schmidt, an associate professor in biology at the University of Illinois at Chicago and a researcher with the Shark Research Institute. “Parthenogenesis is common in insects, and among vertebrates it occurs in some species of fish and reptiles, and strangely enough, in turkeys.”
Reached at her office in Chicago, Schmidt said the news in the small North Carolina aquarium would be an exciting and important development for scientists to follow.
“Genetics study of sharks is a relatively recent thing,” she said. Though scientists have studied the genetics of many animals “sharks with their bad rap kind of lag behind other species in the research that’s being done. It’s only in the last 10 or even five years that there’s been much research at all.”
Parthenogenesis in a few species of sharks in captivity has been documented.
“It can be determined genetically if we have a sample from the pup when it’s born along with a sample from the mom,” Schmidt said. “It’s starting to seem like (parthenogenesis) is a mechanism sharks will use (to reproduce) at least when they’re in captivity and forced to do so. In the wild it’s harder to say.”
The baby shark “is not a clone of the mother because the mother’s chromosomes are not reproduced exactly,” she said. “It will only have chromes that are female. It will not necessarily be identical because it will have a subset of the genome of the mother.”
Pups born through parthenogenesis seem to be normal. Schmidt studied a zebra shark in an aquarium in Dubai that had offspring. “So they can survive and they can be fertile,” she said.
A remote possibility was that Epa could have been impregnated by Guinness, the male shark she came with when ECCO first got both. Female sharks can store sperm for up to three years, Schmidt said. But neither Guinness or Epa was sexually mature when Guinness died, Ramer said.
Ramer said she’s considered every scientific possibility.
“I said, oh ray. Sharks and rays are cousins, we live in the South,” she joked. There’s no documented case of sharks mating with rays.
Ramer and her ECCO workers plan to keep the pup in its egg casing for the full gestation of about 100 days. Once it’s hatched, ECCO could take tissue samples from the pup and Epa. DNA testing would prove once and for all that the birth was through parthenogenesis. She has been in touch with the Georgia Aquarium in Atlanta and one in Chattanooga about DNA testing.
Kortney worked her last day at ECCO last week before leaving for UNC Charlotte. A 2012 graduate of Hendersonville High School, she earned an associate degree in science from BRCC and wants to get dual degrees in environmental biology and psychology at Charlotte.
“We normally don’t name them until they get a little bigger,” she said of the pup. “Sometimes there can be complications because she is a half-clone. Eventually we would have to help her come out of her shell but we’ll wait till that yolk sac is completely gone. It’s kind of a waiting game and watching. You can see she’s moving and there’s water flow because the shell is permeable.”
A parthenogenetic birth would be one more coup for the little aquarium that could. Epa and her pup of virgin birth could attract attention from ichthyologists and geneticists the world over.
“It’s just a click off of being a true clone,” Ramer said. “I’m still waiting for Jeff Goldblum to walk through the door and say, ‘Yes, life has found a way.’ And we’ve got it right here on Main Street. People think we’re nothing. We have some cool stuff going on here, sports fans.”