August 23, 2011

Iberian Lynx Not “Doomed” By Genetics


The Iberian lynx, one of the most endangered cats in the world and Europe´s most endangered carnivore, may not be doomed by its small population size, according to a study published Monday in the journal Molecular Ecology.

Just 250 Iberian lynx are believed to exist in the wild, raising the risks of inbreeding and low genetic diversity.  However, the current study suggests the lynx has had little genetic variability over the last 50,000 years, and that this has not hindered the long-term survival of the species.

Lack of genetic diversity, which is seen in other cat species such as African cheetahs, lions of the Ngorongoro crater and the Florida panther, is typically thought to be the result of population bottlenecks.

However, when geneticists in Spain, Denmark and Sweden extracted DNA from the fossil bones and teeth of Iberian lynx, covering a period of at least the last 50,000 years, they found no genetic variation over that period.

The researchers examined mitochondrial DNA — a part of the genome that is typically highly variable.

"At first this result was very surprising," said lead author Ricardo Rodríguez from the Instituto de Salud Carlos III in Madrid, Spain.

"It is not unusual to see low genetic diversity in living members of a species, but when people have looked at fossil DNA — especially from fossils older than 10,000 years — much more diversity is usually seen."

The researchers were able to show that such patterns are best explained by relatively small long-term population sizes over that period.

"To see so little genetic diversity over such a long period of time indicates that populations sizes were moderate," said study co-author Professor Mark Thomas from the Department of Genetics, Evolution and Environment at University College London.

"But if small populations can exist for so long and with so little genetic diversity then this must say something about the survivability of similar endangered species today."

The Iberian lynx is currently considered the most threatened cat species in the world, with the International Union for Conservation of Nature (IUCN) having classified it as ℠critically endangered´.

Lynx were once widespread across the Iberian Peninsula, but were nearly wiped out due to hunting, habitat destruction and disease.  The numbers of lynx have plunged over the past 50 years, dropping from an estimated 3,000 to approximately 150 in 2005.  The species is now found only in two isolated areas in southern Spain.

Nevertheless, the study indicates that the lynx have continued to thrive, despite their dwindling numbers.

The research “indicates that some species can do fairly well at low population sizes, even for a very long period of time,” said senior author Love Dalen of the Swedish Museum of Natural History.

"Most importantly, these results show that low genetic diversity in the Iberian lynx is not in itself an indication of a population in crisis.”

"What's more, our results may help conservation biologists to assess how large a population needs to be to ensure its long-term survival, something which is a topic of an ongoing debate in many countries, especially for large carnivores."

"One clear message of our study is that a lack of genetic diversity in an endangered species should not hamper conservation efforts" added Dr. Cristina Valdiosera from Copenhagen University.

“It's a myth that certain species are doomed by their genetics. If a species is doomed, it is only doomed by a lack of will to conserve it".


Image Caption: Iberian lynx (Lynx pardinus). Credit: Programa de Conservación Ex-situ del Lince Ibérico/Wikipedia (CC BY 2.5)


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