Topeka Kansas State University assistant professor of biology Eva Horne is keeping her eye on a copperhead snake that’s been living in her house the past several months.
The copperhead, collected from the Konza Prairie in 1998 and initially housed in a laboratory setting, gave birth to two offspring in 2001, after being isolated in captivity for nearly three years. Known as parthenogenesis, the female snake reproduced without her eggs without being fertilized by the sperm of a male copperhead.
In short, the female copperhead cloned herself.
Parthenogenesis occurs naturally in some animal species, such as aphids and some reptiles. But Horne, who had never before witnessed the process, wondered if the copperhead could reproduce on its own in captivity, could the species also clone itself in its natural habitat.
“We have no idea if this occurs in the wild,” she said.
Horne, who is assistant director of the Konza Prairie Biological Station, reported the copperhead’s cloning to K-State biology professor Susan Brown, and two years ago an investigation of the genetic markers of the snakes began.
By that time, only one of the offspring was still alive. However, tissue samples from the yet-year-old deceased baby had been collected for future research.
Horne and Brown joined forces with Tony Grace, K-State post-doctoral research associate, to study the molecular markers of the mother and the babies to determine the similarity of their genes and if the offspring were the exact clones of their mother.
Last year, Sternberg Museum at Fort Hays State University sent samples of copperhead tissue from its collection to K-State to aid in the investigation.
“We used those tissues to isolate DNA to develop (and test) molecular markers,” Grace said, explaining those markers were used to test the mother and the babies in a K-State laboratory.
“We found the mom and her two babies were identical, so the babies were clones of the mother. That led us to conclude (the female copperhead) was the parent and (the reproduction) was not the result of sperm storage,” Brown said.
Female copperheads can store sperm in their bodies for up to six months.
“So this snake can mate with a male or follow the parthenogenesis route,” Horne added.
The next step, Horne said, is to collect pregnant female copperheads from the wild in September, when they typically have their babies, and determine if their offspring have been produced by parthenogenesis or mating with a male.
To do that, the snakes would be brought into the laboratory, where they would have their babies. The DNA of the offspring would be tested, and then the snakes would be released back into the wild.
Horne said she also would like to study parthenogenesis in garter snakes. While all copperhead offspring produced through parthenogenesis are female, garter snake clones seem to be male.
Horne said the research study has a broader application, too.
“A lot of amphibians and reptiles are being endangered, and the more we know about them and how they adapt, the more we can predict what will happen if things (in the environment) change,” she said.
Brown said many aspects of parthenogenesis remain a mystery.
“We still don’t know how or why they do it,” she said.