In recent decades, there have been significant advances in our knowledge of our past thanks to new techniques based on genetic mapping. As this is very new discipline, still learning to define itself and its capacities, there remains a good deal of controversy but this much seems to be reasonable certain: our ancestors or Homo sapiens originated in Africa around 150,000 years ago. A small group eventually left Africa some 80,000 years ago and settled along the coast of South Asia from which they gradually spread out to colonize different parts of the world. All non-Africans in the world today are descended from a small group of south Asians living south of a line from Yemen to the Himalayas, especially from those along the Indian coast. This means that after Africa, India is the second homeland of our human species. Geneticists like L. Cavalli-Sforza and S. Oppenheimer have noted that settlers in the coastal regions of India were the source ('inocula') for the population of India. Some of them later migrated northwards and westward to populate Europe. This is the exact reverse of the various migration-invasion theories (like the Aryan invasion) advanced by linguists and anthropologists who sought to derive Indians and their civilization from Central Asia, Eurasia, or even Europe. See for example, Eden in the East by Stephen Oppenheimer (2003).
This 'founder group', from which all non-Africans are descended, barely survived the fallout from a volcanic eruption in Sumatra known as the 'Toba Explosion', 74,000 years ago. The Toba Explosion was the greatest catastrophe ever to hit humanity. It almost put an end to non-African human populations, but a core group survived in India, which became the jumping off point for the ultimate colonization of the world. This does not mean that there were no non-African humans before the Toba Explosion, but only that descendants of those earlier populations have not survived outside of Africa. Apparently another group out of Africa 120,000 years ago made its way to Egypt but disappeared 90,000 years ago without leaving a genetic trace. This means that the Indian population is largely indigenous from the earliest times of the Toba Explosion and is not the result of recent migrations as held by many historians and anthropologists.
The Europeans were among the descendents from these early South Asians, possibly as recently as 40,000 years ago. South Asia, India in particular, was the jumping off point for the colonization of East Asia, Greater India, Australia and ultimately the Americas.
The data for this is summarized by Luigi Luca Cavalli-Sforza, arguably the world's foremost population geneticist, and his colleagues, in the following words:
"Results show that Indian tribal and caste populations derive largely from the same genetic heritage of the Pleistocene southern and Western Asians and have received limited gene flow from external regions since the Holocene. The phylogeography [neighboring branches] of the primal mtDNA and Y-chromosome founders suggests that these southern Asian Pleistocene coastal settlers from Africa would have provided the inocula for the subsequent differentiation of the distinctive Eastern and Western Eurasian gene pools. " – The Genetic Heritage of the Earliest Settlers Persist Both in Indian Tribal and Caste Populations: by T. Kisilvid, S.Rootsi, M. Metspahi, S. Mastana, K. Kaldma, J. Parik, E. Metspalu, M. Adojan, H.-V. Tolk, V. Stephanov, M. Golge, E. Usanga, S.S. Papiha, C. Cinnioulu, R. King, L. Cavalli-Sforza, P.A. Unterhill and R. Villems. 2003. American Journal of Human Genetics, 72: pp 313 – 332.
Put in non-technical language, it means that the Indian population and all its varied constituents, however defined – upper castes, lower casters, tribal (or so-called indigenous peoples), Dravidians and so forth – are all mainly of indigenous origin, and the contribution of immigrants (gene flow) is negligible. This is a major blow to the many invasion-migration theories that continue to dominate historical discourse in India. In particular, the various theories about Aryans and non-Aryans have no scientific basis whatsoever. In fact, such genetic information calls into question the entire concept of race as a primary factor for explaining the movements of people in ancient history.
Seen against this background, it is natural that the human inhabitants of India and Greater India, like the climate and its flora and fauna, should remain closely related. This is precisely what recent biological studies have also revealed. And this connection goes back at least 50,000 years. It is the descendants of these early humans who created both Indian and Greater Indian civilizations – art, archaeology and literature. Their influence also spread north and west.
This means that contrary to older views that India was mainly populated from the outside in historical times, India has actually been a major source of the world's populations going back many tens of thousands of years, of which the movement at the end of the last Ice Age was the largest and the most important.
Human Migration Timeline:
- 150,000 years ago Modern humans – out mtDNA ancestors – lived in Africa
- 120,000 years ago A group of humans travelled northward through Egypt and Israel but died out 90,000 years ago
- 80,000 years ago A group of humans travelled through the southern Arabian peninsula towards India. All non African people are descended from this group
- 75,000 years ago Modern humans moved east from India to Southeast Asia and China
- 70,000 years ago Humans crossed from Timor to Australia
- 46-50,000 years ago Homo Sapiens entered Europe. Most Europeans today can trace their ancestry to mtDNA lines that appeared between 50,000 and 13,000 years ago
- 40,000 years ago Humans trekked north from Pakistan up the Indus River and into Central Asia
- 40,000 years ago Humans from the East Asian coast moved west along the Silk Road
- 20-30,000 years ago Central Asians moved west towards Europe and east towards Beringia.