Florida panthers gained harmful mutations during rescue efforts

A project that was intended to save Florida panthers may have had unintended consequences, according to a new study led by the University of Central Florida. The experts have discovered harmful mutations in Florida panthers which originated in pumas that were introduced as part of a genetic rescue program.  

By the 1980s, Florida’s panther population had bottomed out at around 30 individuals. Inbreeding within this dangerously small population was causing offspring to be born with genetic defects and diseases. 

In the 1990s, experts introduced pumas from Texas to breed with the panthers. Ultimately, the Florida panther population rebounded to between 120 and 230 adults with greater genetic diversity. However, the new study reveals that the new gene pool has both good and bad mutations present.

“There’s a genetic signal that harmful mutations from different source populations were introduced into the Florida panther population,” explained study lead author Alexander Ochoa. “Although there’s still no evidence of these mutations emerging at the phenotypic level, we want to monitor the genetic health of the Florida panther because things could also go south pretty quickly, especially if their population remains small.”

Ochoa noted that if the fitness of the population begins to decline, wildlife managers should consider future introductions and genetic rescue programs for Florida panthers.

“And if that’s the case, with the information we have in hand, we may be able to assess the genetic health of potential source populations, and pinpoint and select individuals that are best suited for these introductions,” said Ochoa. “Ideally, we would want to select individuals that carry smaller amounts of harmful, or deleterious, mutations for introductions.”

The experts were surprised to find that some of the deleterious mutations were contributed by Central American pumas that were introduced to Everglades National Park during the 1950s and 1960s.

Overall, 16 percent of the deleterious mutations present in Florida panthers are of Central American origin and 33 percent are of Texas origin. In addition, four percent of the harmful mutations are of both Central American and Texas origin.

Using full genome sequencing, the researchers determined that the genetic admixture boosted Florida panther fitness by offsetting the expression of existing harmful mutations. However, the panthers have now become carriers of many new harmful mutations.

“I was expecting that the genetic rescue program was in general beneficial to Florida panthers,” said Ochoa. “But at the same time one of the unexpected findings was that a reasonable amount of novel harmful mutations from different source populations were also introduced into the Florida panther population. And we need to monitor these mutations in current Florida panthers because that’s something that Florida panthers did not have before.”

According to study co-author Professor Robert Fitak, the Florida panther has been a generally positive conservation success story, and that it now can also serve as a model to inform genetic rescues in other species.

“We know that in the future many more species are going to become endangered, suffer from severe inbreeding, and have to be managed by conservation actions such as genetic rescue,” said Fitak. “Our results will help us understand what the potential negative genetic consequences of these actions will be, or what we need to be prepared for.”

The study is published in the Journal of Heredity.

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By Chrissy Sexton, Earth.com Staff Writer