A study on the genetic history of Asian elephants in India has revealed that there are actually five genetically distinct populations in the country, more than earlier estimates. These populations were also found to have diverged from each other much earlier than previously thought, reports Arathi Menon for Mongabay India.
India hosts some 30,000 Asian elephants (Elephas maximus), representing at least 60% of the global population of the species. Researchers from the National Centre for Biological Sciences (NCBS) and the Indian Institute of Science (IISc) collected blood samples from wild elephants in captivity from various parts of India and sequenced their whole genomes.
Previous studies estimated three or four distinct elephant populations in India. But the new study showed there are five genetically distinct ones: three in south India and one each in north and central India.
The researchers identified two geographical features that might have acted as barriers leading to the three populations in southern India: the Palghat Gap and the Shencottah Gap. Both are breaks in the Western Ghats mountain range, an important biodiversity hotspot. One distinct elephant population is found north of the Palghat Gap, while another lives south of it. A third population lives south of the Shencottah Gap.
All five populations seem to have split from each other earlier than previously thought, the study found.
“We believe the central Indian population diverged from the northeastern population around 50,000 years ago. The population north of the Palghat Gap diverged from the northeastern population 70,000 years ago,” study lead author Anubhab Khan of the IISc told Mongabay India. Khan said a subset of the former population “migrated to the south of the Palghat Gap, while a subset from the southern Palghat Gap population moved to the south of the Shencottah Gap approximately 20,000 to 30,000 years ago.”
Khan said it’s not often that such long histories are recorded in wildlife studies.
Conservation ecologist Aritra Kshettry of WWF-India, who wasn’t involved in the study, told Mongabay India the study is a milestone in elephant conservation. He said understanding elephant genomics has implications for identifying individual elephants and estimating their populations, and to trace poached items back to the affected populations.
Study co-author Uma Ramakrishnan from NCBS said the genome sequencing database can also aid conservation prioritization. “Smaller, vulnerable populations, like the one south of the Shencottah Gap, can be better assessed and prioritised for conservation, as the study suggests low genetic variation and high inbreeding in that population,” she told Mongabay India. “Similarly, better connectivity between the northern and northeastern populations is advisable because we don’t want multiple isolated populations there.”
This is a summary of “Genomes map elephant populations, history” by Arathi Menon.
Banner image of a herd of elephants at Jim Corbett National Park in northern India. Image by A. J. T. Johnsingh, WWF-India and NCF via Wikimedia Commons (CC BY-SA 4.0).
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