Ancestry largely derived from South Asia with minor influences from elsewhere
Lakshadweep is an archipelago of 36 islands, scattered over approximately 78,000 square km of the Arabian Sea, 200-440 kms off the south-western coast of India, with population of approximately 65,000. However, the first human settlement of this archipelago is not clear.
The islands were known to sailors since ancient times and historical documents say that the spread of Buddhism to these islands happened during 6th century B.C., Islam in 661 A.D. by Arabians. Cholas ruled the islands in 11th century, Portuguese in 16th century, Ali Rajahs in 17th, Tipu Sultan in 18th before the British Raj of 19th century.
Genetic studies done on the people of the archipelago by a team, led by K. Thangaraj at CSIR-Centre for Cellular and Molecular Biology (CCMB), for the first time have shown that a majority of human ancestry in Lakshadweep is largely derived from South Asia with minor influences from East and West Eurasia. And, there was no evidence of early human migration through the Lakshadweep islands.
“The islands are located between Africa and southwestern part of India. Through our earlier studies we know that early human migration from Africa to Andaman and Australia happened through western coast of India. So, we presumed that Lakshadweep Islands might have played a major role in early human migration and expected the presence of genetic signatures of ancient people, such as Andamanese and Australian aboriginals,” said Dr. Thangaraj, chief scientist at CCMB and a lead author of the study.
DNA samples of 557 individuals from eight major islands for mitochondrial DNA and 166 individuals for Y chromosome markers were analysed.
“We found a strong founder effect for both paternal and maternal lineages — a sign that the island population had limited genetic mixing”, said M. S. Mustak, first author of the study and associate professor of Department of Applied Zoology, Mangalore University.
The authors have studied the major islands of Agatti, Andorth, Bitra, Chetlat, Kadmat, Kalpeni, Kiltan and Minicoy of Lakshadweep and demonstrated a close genetic link of Lakshadweep islanders with people from Maldives, Sri Lanka and India.
“Even after regular historic interactions with people from different regions of the world, it is extremely interesting that we could see only limited number of founders,” said Gyaneshwer Chaubey, another author and professor at Banaras Hindu University.
The results have been published in Scientific Reports on May 6.
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