Genetic study offers good news for endangered Sumatran rhinos


April 26 (Reuters) – A genome study involving the last remaining populations of the Sumatran rhino – a solitary inhabitant of the rainforest – provides what scientists have called good news on the prospects of saving this critically endangered species from extinction extinction.

Researchers said Monday that their study found that the two extant wild populations of this rhino on the islands of Borneo and Sumatra had surprisingly good genetic health and surprisingly low levels of inbreeding.

Experts estimate that only around 80 rhinos remain after a distinct population of the Malaysian Peninsula has become extinct in recent years. The Sumatran rhino – the closest living relative of the woolly rhino that was one of the notable species of the last ice age – is known for its two small horns and a thin coat of reddish-brown hairs.

“With such small population sizes, we expected much higher inbreeding in existing Sumatran rhino populations. So these results were good news for us,” said Nicolas Dussex, postdoctoral researcher at the Center for Paleogenetics in Sweden who helped lead the study published in the journal Nature Communications.

“Moreover, while the plight of the Malaysian population serves as a stark warning of what could happen to the two remaining populations in Sumatra and Borneo, our results suggest that it may not be too late to find ways. means of preserving the genetic diversity of the species, “said Dussex.

Researchers sequenced the genomes of seven rhinos from Borneo, eight from Sumatra and six from the Malay Peninsula population considered extinct since 2015.

The Sumatran rhino is the smallest of the world’s five rhino species, weighing approximately 1,540 to 1,760 pounds (700 to 800 kg). The elusive rainforest inhabitant, the most vocal species of rhino, remains solitary except for mating and rearing offspring. It once had a wide range in Southeast Asia, from the foothills of the Himalayas to Borneo and Sumatra.

Poaching and man-made destruction of homes have devastated its population, with numbers falling by around 70% over the past two decades.

“When it comes to the long-term survival of a species, genetic diversity is one of the key factors, as it allows adaptation to future environmental changes and disease,” said Johanna von Seth, doctoral student and lead author of the study at the Center for Palaeogenetics. “So the fact that there is still a lot of diversity is very promising if we manage to maintain it, assuming of course that we can reduce the impact of non-genetic factors as well.”

The researchers said that steps such as translocation of rhinos for mating – a costly and logistically difficult proposition – or the use of artificial insemination could enable a beneficial exchange of genes between the populations of Borneo and from Sumatra. This species has shown low breeding success in captivity and faces a high risk of inbreeding – mating with close relatives – in the wild due to its small numbers.

Inbreeding creates an increased risk of genetic defects and reduced genetic diversity. Scientists feared that reports of tumors and low fertility among these rhinos could be evidence of a dangerously inbred population.

“It’s important to remember that the Sumatran rhino is still on the brink of extinction due to non-genetic factors,” said Love Dalén, professor of evolutionary genetics and co-author of the study at the Center for Palaeogenetics.

“So the hope, albeit small, that these results offer is that if we can resolve the problems caused by habitat destruction and poaching, there is at least a chance that the survivors will not be doomed. by their poor genetic status, ”added Dalén. .

Reporting by Will Dunham in Washington, editing by Rosalba O’Brien

Our Standards: The Thomson Reuters Trust Principles.

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