Key Findings on Indian Elephant Migration and Genetic Diversity

Source: The post on Key Findings on Indian Elephant Migration and Genetic Diversity is based on the article “Indian elephants lost genetic vigour as they moved north to south, 5 distinct populations exist: Study” published in “Indian Express” on 30th september 2024.

Why in the News?

Recently, Researchers from Bengaluru’s National Centre for Biological Sciences (NCBS) and the Indian Institute of Science (IISc) have discovered that Indian elephants migrated southward over millennia, progressively losing genetic diversity with each migration.

Key Findings on Indian Elephant Migration and Genetic Diversity

1. Migration from North to South:  Indian elephants migrated progressively from the north to the south over several millennia. This movement led to a loss of genetic diversity, with the southern populations showing reduced genetic vigour.

2. Five Genetically Distinct Populations: Researchers identified five genetically distinct elephant populations across India:

a) Northern population along the Himalayan foothills (Northwest to Northeast).

b) Central Indian population located in parts of central India.

c) Three Southern populations distributed across Tamil Nadu and Kerala, south of the Shencottah Gap.

3. Southernmost Population and Genetic Diversity: The southernmost population, south of the Shencottah Gap, has the lowest genetic diversity, making it highly vulnerable. This isolated population consists of fewer than 150 elephants and faces a higher risk of extinction.

4. Historical Divergence of Populations: The northern population diverged from the others over 70,000 years ago. Central Indian elephants diverged around 50,000 years ago. The three southern populations separated approximately 20,000 years ago.

5. Serial Founder Effect and Inbreeding Risk: As elephants migrated southward, the reduced population sizes led to the serial founder effect. This phenomenon increased the risk of inbreeding depression, where harmful genetic traits are more likely to be passed down.

6. Southern Barrier: The study revealed that the Shencottah Gap acted as a natural barrier, further dividing the southern elephant populations. This was previously unrecognized, with the Palghat Gap thought to be the only barrier in the Western Ghats.

7. Central and Northern Populations: Central Indian elephants are found between southwest West Bengal and eastern Maharashtra, forming a distinct population. Northern elephants, in the Northwest (Uttarakhand, Uttar Pradesh) and Northeast (Assam, Arunachal Pradesh), are separated by the Ganga and Brahmaputra rivers but were historically connected.

8. Importance of Habitat Connectivity: The study stresses the need to maintain habitat connectivity, especially in the Western Ghats, where infrastructure development has disrupted gene flow between populations.

UPSC Syllabus: Environment