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Sunday, July 22, 2018

Local Students Partner with Phoenix Zoo to Save Native Frog

Students at a South Phoenix charter school this fall will give more than lip service to environmental issues: They’ll do hands-on research that is helping to save a threatened species, the Chiricahua leopard frog.

The project started with five students at Arizona Agribusiness and Equine Center’s Paradise Valley campus in the spring and will expand in August to include the South Mountain campus on Baseline Road and Red Mountain campus in Mesa.

Five or six students at each school will be involved in genetic research in partnership with the Phoenix Zoo.

Here’s how it works: Arizona Game and Fish staff and volunteers, including zoo staff, collect frogs from the wild. The zoo breeds them and releases the offspring back into their habitat, hoping they’ll continue to breed and increase their numbers.

The catch? “There’s a problem with endangered species,” said Dr. Mike Brown, chair of the school’s science department. “The gene pool gets quite small.”

So Brown and the students use DNA sequencing to determine how closely related the frogs are.

“His work will improve the genetic diversity and we’ll get healthier populations,” said Dr. Dean Rice, executive vice president of the Phoenix Zoo. “For high school kids to be doing this work is dynamic.”

Taylor Lasley of Phoenix, a junior at the Paradise Valley campus, was involved in the research last semester. She has known since second grade she wanted to work with animals and plans a career working with endangered species in the rainforest.

“A lot of conservation work you do, you need the genetic research,” she said.

She and another student won the FFA Agriscience Fair June 12 in Tucson and will compete in the nationals in October.

This kind of experience is important for any student looking toward a career with wildlife, even closer to home.

“The years of zoos being places of passive observation are gone,” Rice said. “We’re all into conservation.”

One reason Brown chose to study the Chiricahua leopard frog is because the international Association of Zoos and Aquariums named 2008 the year of the frog.

“Amphibians are topical,” Brown said. Of about 2,000 species in the wild, one-third face extinction. This particular frog could be extinct within a few years if not for the zoo’s efforts. “The Chiricahua leopard frog is almost totally wiped out,” Rice said.

Invasive species such as bullfrogs and crayfish are partly to blame; so is a fungal disease and the disappearance of habitat.

Brown also chose this frog because it’s native to Arizona.

So far, the zoo has raised and released 7,000 frogs back into their native habitat around the Mogollon Rim and in southern Arizona, mainly near Ramsey Canyon. But it’s difficult to track the survival rate, Rice said. The large numbers make it cost-prohibitive to use a marking system, and they also move around a lot.

But the less related the frogs are, the greater their chances of living and of breeding healthy offspring. As with humans and many other creatures, inbreeding weakens the population by increasing the risk of deformities and disease.

It’s not easy to decipher which frogs are family and which are not. Getting frog DNA in a non-invasive way is a messy business.

“Frogs are kind of dirty and scummy and covered in bacteria and fungus,” Brown said. “It you’re taking a sample of DNA from the outside of a frog, a great deal of it will be from other creatures.”

They found a commercial DNA testing kit that works well, though. After that, they use a machine called a PCR, or polymerase chain reaction, which is like a DNA photocopier. The students copy sections of frogs’ DNA and compare them to figure out how inbred the frogs are or aren’t.

“The trick is knowing where to copy,” Brown said.

This will allow the zoo to choose less inbred frogs to mate. After that, the egg masses are stored in tanks like aquariums at the zoo and raised into mature frogs for release.

While one goal of the program is to bring a threatened species back from the brink, another is to boost numbers of a different sort: “The grand overall plan is to get more students interested in biotechnology as a career,” Brown said.


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