By Sarah Rubinstein | Bond LSC
As animals face increasing pressure from habitat loss and changing climate in the wild, zoos worldwide strive to reinforce diversity for at-risk populations among their inhabitants.
So, when Rachel Carroll took charge of creating a genetic blueprint for the fishing cat — a feline native to Southeast Asia — she had one eye toward helping the often-overlooked “grumpy, overgrown house cat.”
“We’re hoping that we can really showcase the power that genetics can play in understanding not just the organism but diseases that could be occurring within them as well,” said Carroll, research specialist and lab manager in the Wes Warren lab at Bond Life Sciences Center.
Fishing cats were the heart of Carroll’s masters project she started in 2020. This species stands out from other cats with its affinity for water, unique swan diving technique used to catch food and moody personality. The International Union for Conservation of Nature lists these cats’ conservation status as “vulnerable,” and zoos have found that older fishing cats have a higher prevalence of bladder cancer.
Published in Nature’s Scientific Reports, Carroll’s effort to create a reference genome partly aimed to find gene mutations in fishing cats potentially linked to bladder cancer. Using genes from 11 cats at zoos across the country — some with bladder cancer and some cancer free — she looked at the cat equivalent of 152 genes known to increase cancer risk in humans, with 10 of those specifically linked to bladder cancer. That allowed her to identify a specific cat gene mutation that could lead to higher rates of bladder cancer. Since only 25 fishing cats are captive in U.S. zoos, many share a genetic pedigree that may result in higher rates of inherited disease.
“The work includes taking genetic sequences from affected cats — cats that are cancer free — and comparing those sequences to a reference genome for that species to see the differences and similarities within the sequences of these cats,” she said.
Creating the genome required mastering bioinformatics, a challenge Carroll welcomed. After learning to code, she operated Mizzou’s supercomputer to synthesize the complete genome.
She used a variety of bioinformatic programs to analyze if the fishing cat genome contains similar gene sequences to the known cancer risk genes in humans, and then she identified these mutations within the 11-cat dataset. Next, she used another program to determine if these mutations have a harmful effect on the organism.
Carroll found the gene BRCA2 to be more prevalent in cats with cancer compared to cats without, however, since her sample size was small, she cannot definitively say that this gene causes cat bladder cancer.
Carroll noted this study is just a jumping off point for exploring the genome of this species and, ultimately, promoting conservation. By understanding the genetic basis of diseases like bladder cancer, conservationists can develop better strategies to protect fishing cats and other endangered species. Zoological institutions will also have information to guide better management strategies to help decrease the chances of disease occurrence in a smaller population.
Carroll noted other major factors impact animal populations that are important to consider. Heavy deforestation, aquaculture development and farming development all lead to habitat loss, which is a danger to these cats as well.
“Habitat loss is really the biggest driver and risk factor for all species on Earth right now,” she said. “And, unfortunately, until we can get a really good hold on that, it’s really hard to find ways to promote conservation efforts since that’s happening so rapidly.”
For now, she’s happy to increase interest in these lesser known apex predators to show fishing cats are just as essential to their natural ecosystems as other big cats.
“That’s something I really pride myself on, being able to communicate science better to people so that we can actually have action and excitement about trying to make the world and the environment a better place for us and everything else that’s living in it,” she said.