Using three-decade-old samples, a group of scientists have at last mapped the genome of Florida’s state animal, the Florida panther.
They also mapped the genome of the Texas cougars that were imported to breed with the panthers in 1995 to keep them from going extinct.
Their next step is to analyze the results and see what changes that crossbreeding might have caused in the panthers’ genetic makeup, according to Melanie Culver, a University of Arizona biology professor who is one of the co-authors of a just-published scientific paper about the study.
The cross-breeding of the two closely related animals was a last-ditch experiment that had never been tried before to save an endangered animal that was suffering from genetic defects.
Prior studies have shown that it succeeded in curing the panthers’ genetic defects and caused a population boom. Fewer than 30 panthers prowled the Florida wilderness in 1995, and now biologists estimate the number is more than 200.
The just-published study found that the cross-breeding “increased the genetic diversity among panthers by a factor of three,” said Alex Ochoa, a scientist and lead author on the project. The higher genetic diversity means the panthers are healthier and are less liable to be wiped out by a disease.
What’s not clear is what else may have happened as a result of the cross-breeding.
“We want to know how the two genomes mixed,” Culver said. “Did everything in the Texas genome benefit the panther? Or was something detrimental? Or was it neutral?"
Those changes, if any, should be clear because “this is 10 generations later” among the revived panther population, Culver said.
There are other avenues to explore, too.
“It opens the door for a much finer scale assessment of panther genetics to assess not only genetic variation but also differences with other populations of pumas,” said Florida Fish and Wildlife Conservation Commission panther biologist Dave Onorato, another co-author.
The work is based on samples that a University of Florida veterinarian named Melody Roelke collected in the late 1980s when she accompanied the state’s biologists in tracking down and putting radio collars on the panthers.
She discovered that the number of panthers had dwindled so low that they were inbreeding. As a result genetic defects were cropping up. Panthers had developed sharply crooked tails, holes in their hearts and deformed testicles that would prevent them from having offspring. The males’ sperm was barely viable too.
Initially state wildlife officials tried a captive breeding program to save the panthers, but the cats they captured to use in the captive breeding all had the same genetic problems. That led to the unprecedented decision to bring in the Texas cougars, a close cousin of the panther, and refresh the gene pool.
Of the eight cougars imported from Texas, only five successfully bred with male panthers. But that was sufficient to save Florida’s state animal from sliding into oblivion.
This new study is based on the genetic samples that Roelke took before that cross-breeding experiment.
“When I performed the first set of genetic tests in 1986, the techniques were so limited that we could not see any differences between any of the panthers,” Roelke said in an email to the Tampa Bay Times about the new study.
Better genetic testing techniques have come along, she said, and “33 years later, analyzing some of the identical samples that I collected so long ago, Alex Ochoa has been able to sequence the entire genome, one base pair at a time! Pretty remarkable.”
Culver estimated that taking the next step in the genome study may take about a year.