19th July 2013
When did modern man (Homo sapiens sapiens) first enter India?
While on the subject of ancient Indians, there is currently some uncertainty regarding when modern man (Homo sapiens sapiens) entered India. Two alternative theories are currently found in the literature. Both are very sturdy theories, but on balance, after reviewing the articles, I'm currently inclined to agree with the 50-60,000 year theory.
Theory 1: Modern man entered India up to 120,000 years ago from Africa
This theory uses as key basis a 2007 paper published in Science, to demonstrate evidence of specific types of stone age tools that only modern man could have produced.
I'm extracting key sections from this paper, below. Paper: "Middle Paleolithic Assemblages from the Indian Subcontinent before and after the Toba Super-Eruption", by Michael Petraglia, Ravi Korisettar, Nicole Boivin, Christopher Clarkson, Peter Ditchfield, Sacha Jones, Jinu Koshy, Marta Mirazón Lahr, Clive Oppenheimer, David Pyle, Richard Roberts, Jean-Luc Schwenninger, Lee Arnold and Kevin White, Science, New Series, Vol. 317, No. 5834 (Jul. 6, 2007), pp. 114-116
The Youngest Toba Tuff (YTT) eruption, which occurred in Indonesia 74,000 years ago, is one of Earth's largest known volcanic events. The Indian subcontinent contains extensive YTT deposits (13-15). Here we associate the YTT with archaeological assemblages at Jwalapuram, in the Jurreru River valley of southern India. Broad continuity of Middle Paleolithic technology across the YTT event suggests that hominins persisted regionally across this major eruptive event.
Here we describe an archaeological sequence from south India that includes a substantial YTT layer and sheds light on the eruption's impact on climate, environments, and hominin populations.
In the Kurnool District of Andhra Pradesh in southern India, stratified archaeological sites in the Jurreru River valley contain stone artifacts in association with faunal remains in caves, rockshelters, and open-air localities. The archaeological record spans all periods of the Paleolithic.
The Jwalapuram ash is a distal deposit of the YTT, based on its close similarities with proximal deposits of YTT in Sumatra and with previously characterized distal occurrences in India. Jwalapuram locality 3 preserves more than 7.5 m of sedimentary deposits, including a 2.55-m-thick deposit of ash, and a sequence of lithic artifacts that straddle the ash layer.
Soft sediment deformation structures suggest that the tephra initially accumulated on a wet clay substrate, probably in a lacustrine environment. The abrupt transition from light gray ash to an orange (but still ash-rich) silt horizon immediately above the ash sequence represents a major change in depositional regime.
The stone tool assemblages were found in trenches placed across the landscape (that is, at Jwalapuram localities 3, 17, and 21). At Jwalapuram locality 3, we used optical dating to obtain burial ages for sediment samples from archaeological layers above (JLP-380) and below (JLP3A-200) the ash. Ages of 77 +- 6 and 74 +- 7 ka were obtained for the pre- and post-Toba samples, respectively.
The pre-Toba archaeological layer at locality 3 contained 215 artifacts as well as a piece of red ochre that shows striations due to use. This stone tool assemblage consists of faceted unidirectional cores made from limestone (60%), quartzite (22%), and chert (11%), with elongate parallel flake scars indicating the production of blades. Frequent preparation of flake platforms is seen, suggesting that these flakes were struck from prepared cores similar to those found at the site. A small proportion of flakes were retouched into notches, informal scrapers, retouched blades, and a burin (Fig. 2). [Click for larger image]
We provide here firm chronological evidence that hominins were present in the Jurreru River valley, south India, immediately before and after the YTT eruption. Analyses of the archaeological industries recovered from the site indicate a strong element of technological continuity between the pre- and post-Toba assemblages. Together with the presence of faceted unidirectional and bidirectional bladelike core technology, these pre- and post-Toba industries suggest closer affinities to African Middle Stone Age traditions (such as Howieson's Poort) than to contemporaneous Eurasian Middle Paleolithic ones that are typically based on discoidal and Levallois techniques.
The coincidence of (i) evidence of hominins flexible enough to exhibit continuity through a major eruptive event, (ii) technology more similar to the Middle Stone Age than the Middle Paleolithic, and (iii) overlap of the Jwalapuram artefact ages with the earlier end of the most commonly cited genetic coalescence dates may suggest the presence of modern humans in India at the time of the YTT event. This interpretation would be consistent with a southern route of dispersal of modern humans from the Horn of Africa; the latter, however, will remain speculative until other Middle Paleolithic sites in the Indian subcontinent and Arabian Peninsula are excavated and dated.
Theory 2: Modern man entered India 50-60,000 years ago from Africa
Last month, Professor Richards et. al. published his rebuttal of this theory by drawing on a greater body of DNA evidence that was available for the earlier article. (Proceedings of the National Academy of Sciences of the United States of America)
"One of the things we didn't have in 2005 was very much evidence from India in the way of mitochondrial sequences. Now, with a lot of people doing sequencing and depositing material in databases there are about 1,000 sequences from India," said Professor Richards.
By using the mitochondrial DNA of today's populations and working backwards, and by drawing on a wide variety of other evidence and research, the team was able to make much more precise estimates for the arrival of modern humans in India.
The evidence suggests dispersal from Africa and settlement in India no earlier than 60,000 years ago.
"We also argue that close archaeological similarities between African and Indian stone-tool technologies after 70,000 years ago, as well as features such as beads and engravings, suggest that the slightly later Indian material had an African source," states Professor Richards.
"There were people in India before the Toba eruption, because there are stone tools there, but they could have been Neanderthals – or some other pre-modern population," he added. [Source]
I'm citing a diagram and extract from the article, below [click for larger image]
"Genetic and archaeological perspectives on the initial modern human colonization of southern Asia" by Paul Mellarsa, Kevin C. Goric, Martin Carre, Pedro A. Soaresg, and Martin B. Richardse, PNAS June 25, 2013 vol. 110 no. 2610699-10704.
We find no evidence, either genetic or archaeological, for a very early modern human colonization of South Asia, before the Toba eruption. All of the available evidence supports a much later colonization beginning ~50–55 ka, carrying mitochondrial L3 and Y chromosome C, D, and F lineages from eastern Africa, along with the Howiesons Poort-like microlithic technologies. We see no reason to believe that the initial modern human colonization of South and Southeast Asia was distinct from the process that is now well documented for effectively all of the other regions of Eurasia from ~60 ka onward, even if the technological associations of these expanding populations differed (most probably for environmental reasons) between the eastern and northwestern ranges of the geographical dispersal routes.
How far one can make a case for potentially much earlier expansions (in mtDNA terms, pre-L3) from Africa into adjacent areas of Asia is a separate issue, for which the current evidence remains more debatable. The skeletal evidence from Skhul and Qafzeh in Israel demonstrates that for a limited period around 100–120 ka, populations of anatomically modern form dispersed from northern Africa into the immediately adjacent areas of the Levant (at the extreme northern limit of the East African Rift Valley system), apparently in response to an episode of sharply increased humidity, alongside other elements of Afro-Arabian fauna. As discussed in Archaeology, the same case can be made (with rather less confidence) for the western parts of the Arabian peninsula at around the same time, on the basis of the distinctive forms of “Nubian” technology of presumed (although still not demonstrably so) northeast African origins. With this precedent in mind, one could suggest that the same, or a similar, dispersal, could have carried these intrusive African populations farther to the east, conceivably as far as India, and potentially well before the Toba eruption.
However, this scenario encounters major problems on both archaeological and genetic grounds. The archaeological evidence initially advanced to support an earlier (pre-Toba) dispersal of African-derived populations to southern Asia has since been withdrawn by the author responsible for the original lithic analyses, who now suggests that they are most likely “the work of an unidentified population of archaic people” (ref. 11, p. 26). Meanwhile, the genetic evidence outlined earlier indicates that any populations dispersing from Africa before 74 ka would predate the emergence of the mtDNA L3 haplogroup, the source for all known, extant maternal lineages in Eurasia. The size of the mtDNA database is very substantial: currently there are almost 13,000 complete non-African mtDNA genomes available, not one of which is pre-L3. One would therefore need to postulate the complete extinction of these earlier, non-L3 lineages over a vast region of Asia, from the Near East to southern India (a distance of at least 5,000 km), despite the populations in question belonging to anatomically modern Homo sapiens form, for which intermixture and interbreeding with the subsequently dispersing L3-carrying groups would presumably have been inevitable and widespread. The present lack of any discernible evidence for these pre-L3 lineages in any surviving Eurasian population or for any similarly ancient Y chromosome lineages argues against substantial intermixture with earlier resident groups and poses a final obstacle to the hypothesis of an early, pre-Toba modern human colonization of South Asia.