Iran's critically endangered cheetahs are the last remaining survivors of a unique, ancient Asian subspecies, genetics experts reveal.
New analysis confirms Iran's cheetahs belong to the subspecies Acinonyx jubatus venaticus. DNA comparisons show that these Asiatic cheetahs split from other cheetahs, which live in Africa, 30,000 years ago.
Researchers suggest that Iran's cheetahs must be conserved to protect the future of all cheetahs.
Cheetahs formerly existed in 44 countries in Africa but are now only found in 29.
Historically, they were also recorded across southwest and central Asia but can now only be found in Iran.
Scientists have previously said that cheetahs have low genetic variability, theorising that a "population crash" approximately 10,000 years ago led to inbreeding in the species.
Despite this, five 'different' subspecies are currently described according to where they live.
Genetic studies in the 1990s confirmed cheetahs found in southern Africa (A. j. jubatus) and east Africa (A. j. raineyi) as separate subspecies.
However, it has not been clear whether populations in west Africa (A. j. hecki), northern-east Africa (A. j. soemmeringii), and north Africa and Iran (A. j. venaticus) are genetically different enough to deserve their current status as subspecies.
Aiming to solve the puzzle of modern cheetahs' origins, scientists from the University of Veterinary Medicine in Vienna, Austria have been working in collaboration with the Iranian Department of Environment and wildcat conservation group Panthera.
Their findings are published in the journal Molecular Ecology.
Dr Pamela Burger and her team analysed the DNA of cheetahs from a wide geographical and historical range, including medieval remains found in north-western Iran.
"With our data we prove that current Iranian cheetahs represent the historical Asiatic subspecies A.j. venaticus as they share a similar genetic profile with specimen originating from northwestern Iran in 800-900 CE," explains Dr Burger.
The researchers have also been able to distinguish Iranian cheetahs from their nearest neighbours in northern-east Africa which were confirmed as A. j. soemmeringii.
Cheetahs in north Africa, previously considered the same subspecies as those in Iran, were actually found to have more in common genetically with those in west Africa.
By comparing sequences in the DNA, researchers have found that the unique Asiatic cheetahs separated from the rest of the species in southern Africa over 30,000 years ago.
Dr Burger explains that because this split occurred long before the theorised population crash, A.j. venaticus represents a highly distinct lineage.
"The implications of our discovery are that the confirmation of the subspecies is a basis for future conservation management. If the aim is to conserve this biodiversity, subspecies should not be mixed," she says.
Currently estimated at just 60-100 individuals with less than half at mature breeding age, the Iranian cheetah population is classified as critically endangered by the IUCN Red List.
Together with the United Nations Development Programme, Panthera and the Wildlife Conservation Society the Iranian Department of the Environment has established a programme to make conservation of the Asiatic cheetah a national priority.
Conservationists are concerned that time is running out for Iran's cheetahs.
"We have been successful in stabilising numbers in Iran but we still have a long way to go before we can consider this unique sub-species secure," says Alireza Jourabchian, Director of the Conservation of the Asiatic Cheetah Programme (CACP) in Iran.
Threats facing the small population include overhunting of cheetah prey, habitat degradation and direct poaching.