Florida Panther Genetics
The Florida panther once ranged throughout the southeastern United States but its numbers were drastically reduced from years of persecution and habitat destruction until the only remaining members that survived were in south Florida. In the early 1970’s the panther went through a genetic bottleneck, barely escaping extinction, and it’s theorized there may have been only 6 individuals in the population (Culver et al, 2008). This very lower number lead to severe inbreeding that caused several maladies.
Genetic studies have revealed that panthers in south Florida may belong to two distinct stocks (O'Brien et al. 1990; Roelke et al. 1993): those in the Everglades and those in Big Cypress. Everglades panthers may be descended from seven captive South American pumas released into Everglades National Park between 1957 and 1967 from the Piper Collection of Everglades Wonder Gardens in Bonita Springs, Florida. This idea is supported by lower frequency of kinked tails, cowlicks, and cryptorchidism in Everglades panthers (Roelke 1993).
Findings of a population viability analysis in 1992 speculated that the Florida panther would become extinct in 24-63 years due to its small population size and associated inbreeding (Seal et. al. 1992). A plan for genetic restoration was prepared in 1994 to reduce the occurrence of inbreeding, restore genetic variability and vitality, and restore genetic diversity levels to that typical of other puma subspecies (U. S. Seal, 1994). In 1995 8 female pumas from Texas (Puma concolor stanleyana) were released throughout Florida panther range in south Florida to alleviate the genetic problems plaguing this isolated and inbred population. Texas pumas were chosen because they are the closest living relative to the Florida panther and one which they historically interbred with. Five of the eight Texas pumas produced offspring. Five died in the wild from various causes and the remaining three were removed to captivity during the 2002-2003 capture season after they contributed to Florida panther genetic introgression efforts. These efforts reestablished a healthy and diverse Florida panther gene pool and reduced the frequency of several of the inbreeding depression indicators such as atrial septal defects (holes in the heart), cryptorchidism (undescended testicles), kinked tails and cowlicks. Because the Florida panther population remains isolated it will likely become necessary to enrich the population, as before, by releasing females from other populations at some point in the future. Scientists are carefully monitoring the population to determine when this becomes necessary.
A common misconception held by some people is that genetic introgression has eliminated the “pure” Florida panther. Before the panther became artificially isolated through hunting and habitat loss, the coryi subspecies interbred with couguar to the north and stanleyana to the west. This mixing of genes is what kept all populations healthy including the original, pre-Columbian Florida panther. The goal of genetic introgression was not to replace the characteristics that make coryi unique but rather to restore its historic and healthy genetic variation. Because of the way wild panthers move throughout their habitat the level of gene mixing was diverse. Genetic analyses have revealed that the amount of genetic admixture in individuals ranges from a little to a lot. There are even panthers out there that remain uninfluenced by stanleyana genes.
Recent genetic studies suggest that all North American Puma became extinct during the late Pleistocene era. Subsequently, they recolonized the continent and are believed to be comprised of a single subspecies according to one analysis (Culver et al 2000). This study further suggests that only six subspecies of puma, instead of 30, should be recognized range-wide throughout North and South America. Despite this new genetic evidence these classifications have yet to be unanimously accepted. Even if the scientific classification of the Florida panther were to change it would still be protected under the Endangered Species Act as an endangered population.