Endangered since the appearance twenty years ago of a cancer ravaging the species, the Tasmanian devil may escape extinction. How can this be? To understand this, you have to look at the genetic evolution of the species.
Since the 90’s, the Tasmanian devil has been struck by an incurable disease: facial cancer or Devil facial tumor disease (DFTD), which is also contagious. Considered endangered, this animal endemic to the island of Tasmania, since its eradication from Australia, has been the subject of numerous studies.
The latest was carried out by an international team and reported in an article by Andrew Stofer, a specialist in the ecology of infectious diseases, published in the journal Nature. Thus, the genomes of 294 Tasmanian devils were assiduously compared, samples having been obtained before the appearance of DFTD. The researchers were then able to highlight two small portions of the genome (containing seven genes) having evolved in the space of only four to six generations.
“Overall, our results indicate a rapid evolutionary response to the strong selection imposed by DFTD; we have never seen a response to such a lethal pathogen in wildlife populations before.” explain Andrew Stofer and his team from the University of Washington (USA).
In other mammals, five of these seven genes are linked to cancer and immune responses, suggesting that the Tasmanian devil develops a species-wide resistance to this disease.
« We hope that the evolutionary response we have discovered will increase Tasmanian Devil survival from this devastating disease. » continues Andrew Stofer.
The devastating side of DFTD is not to be taken lightly since a study published by the Ecological Society of America (ESA) in 2009 announced the end of the species before the appearance of this famous genetic evolution. Fatal in almost 100% of cases, the DFTD has been decimating the Tasmanian devil since 1996, having caused the disappearance of 80% of its workforce for a presence in 95% of the territory.
“Seven years ago, I published models that predicted that these devil populations should now be extinct. I’m very glad I was wrong. » says one of the study’s co-authors, Professor Hamish McCallum of Griffith University (Australia).
The researchers hope that the results obtained, as regards the beneficial genetic evolution of the Tasmanian devil, will be able to contribute to making a selection of specimens carrying this genetic resistance and which will be bred in captivity for the survival of the species.
Sources: Tribune de Genève – MotherBoard