STATE COLLEGE, PENNSYLVANIA--Pumas are known by many names--panther, jaguar, and cougar among them. Indeed, experts on the animals thought they were so genetically diverse as to constitute a menagerie of 32 subspecies. Now an extensive genetic analysis has turned up just six puma subspecies. The finding, reported here on 12 June at the annual meeting of the American Genetics Association, sheds light on the evolution of the 60-kilogram cats and suggests that keeping some of these supposed "subspecies," such as the Florida panther, from becoming extinct may be easier than previously thought.
As part of a DNA study of the world's cats, Stephen O'Brien and his team at the National Cancer Institute (NCI) in Frederick, Maryland, collected blood and tissue samples from 209 puma in zoos, museums, and the wild across North and Central America, and from 106 of the animals in South America. They then looked for sequence differences in three mitochondrial genes and 10 microsatellites, short bits of repetitive DNA sequence that lengthen and mutate through time and thus indicate the relatedness of organisms.
The researchers found no differences in the mitochondrial DNA from North American pumas, and their microsatellites were "virtually indistinguishable," NCI's Melanie Culver reported at the meeting. This suggests that only one kind of puma inhabits North America, rather than the 15 subspecies previously identified on the basis of where they live and differences in appearance. The DNA analyses also showed that only one subspecies lives in Central America and that just four others prowl South America. The NCI team found the most genetically diverse pumas in Paraguay and Brazil south of the Amazon River. This indicates that these populations are the oldest, dating back some 250,000 years, and that northward migrations gave rise to the others over time, Culver adds.
The work is "a tour de force," says Oliver Ryder, a geneticist at the Zoological Society of San Diego. Moreover, with North American pumas so closely related, zoos should be able to breed the endangered Florida panthers with other animals without fear of contaminating that "subspecies" with the genes of another, notes geneticist James Womack of Texas A&M University in College Station. On the other hand, they will have to travel quite far if they hope to introduce more diversity into North American pumas.