The existence of five genetically-distinct populations of Asian elephants in India, more than previously thought, has been revealed in a recent study published in Current Biology.
‘’Divergence and serial colonisation shape genetic variation and define conservation units in Asian elephants’, authored by Uma Ramakrishnan’s group at the National Centre for Biological Sciences, in collaboration with Raman Sukumar and others at the Indian Institute of Science, have uncovered new insights into the genetic history of India’s Asian elephants.
60% of global population
“India is home to 60% of the global population of Asian elephants, found across South and Southeast Asia. Today, Asian elephant habitats in India are fragmented, surrounded by farmland, human settlements, commercial plantations, and linear transport infrastructure. This has resulted in widespread and often severe human-elephant conflicts. Despite their ecological and cultural significance, studies on the population genetic structure, diversity, and demographic history of these elephants—critical for identifying conservation and management units—have been limited,” said a release.
The study, which analysed whole genome sequences from captive and wild elephant blood samples collected across diverse landscapes, offers new hope for the species’ future by identifying key populations that need tailored conservation strategies.
The research identified five elephant populations spread across Northern, Central, and Southern India. Two populations in the north and three in the south. Historically, elephants migrated from the north to the south, but with each migration, their genetic diversity declined.
Anubhab Khan, the study’s lead author and faculty member at the Indian Institute of Science, Bengaluru, explained that this reduced genetic variation could be the result of a serial founder effect, where fewer individuals from each starting population migrate to establish new populations. As these populations become smaller, the risk of inbreeding depression increases — a phenomenon where harmful genetic variants are more likely to be inherited due to breeding among related individuals.
“The results also align with previous research, showing that the Northwest and Northeast Indian populations, nestled in the foothills of the Himalayas, are genetically distinct from other Indian populations. The Ganges and Brahmaputra rivers are potential barriers to gene flow in these regions.”
Lowest genetic diversity
The release further added that the southernmost population, located south of the Shencottah Gap, has the lowest genetic diversity and is particularly vulnerable. With fewer than 50 elephants remaining, Prof. Ramakrishnan warned that this population has a higher chance of extinction. The researchers suspect that recent development along a railway line, a highway, and other transportation infrastructure may have further reduced gene flow between northern and southern populations. The researchers advocate carefully considering any translocation of animals across the gap.
The identification of these five genetically-distinct populations underscores the need for region-specific conservation efforts. The research team also plans to develop a genetic toolkit based on DNA extracted from elephant faeces. This toolkit will help monitor populations more accurately and identify individual elephants in the wild, providing invaluable data for conservationists.
Published - September 28, 2024 10:49 pm IST
