Saturday, 26 March 2011

A Third Eurasian Neolithic Revolution?

Recently there has been much talk in the ADMIXTURE-fiddling blogs about the origin of Ancestral North Indian (ANI) vs Ancestral South Indian (ASI). While ANI increasingly appears to be a Fertile Crescent derived population, ASI remains somewhat of a mystery, although some minor Yellow River-derived population may have also had a role.
Assuming an exceptionally fast and thourough cultural-biological Human Revolution followed by (near) complete replacement model, one would expect ASI to necessarily have undergone sufficient adaptations to be able to survive the onslaught of better adapted Fertile Crescenters and Yellow Riverers. It was necessarily more than just being at the right time and place to learn and get seeds from a neighbouring agricultural people. A whole new way of thinking and cooperating was likely needed... Since there is no archaeological evidence of an independent invention of agriculture in South/SouthEast Asia, and complete replacement from both known Core Areas is against the genetic evidence here, it would seem that the model fails to explain the facts and thus must discarded or much modified.

There are however some indications of a 3rd, perhaps less complete from an archaeological point of view, Neolithic Revolution in Eurasia.
Firstly, one other area, in addition to the Fertile Crescent and Yellow River areas, is thought to have independently invented quite advanced agriculture.
Secondly, several crops still grown in South Asia and South East Asia were not brought over from China or then Middle East by agriculturalists, and it's likely they were domesticated locally. It's quite rare for an already "Neolithic" society to domesticate new plants. We still rely on ancient ones, and the first independent domestication of a food plant in Europe was apparently the strawberry and that happened only in the 18th century... (rye was adapted in Northern Europe but it probably already grew as a contaminant of better cereals back in the Near East).
South Asia's crops are also less productive crops that no farmer already possessing the likes of wheat, barley or rice would care about labouriously domesticating.
One, sugar cane is well known today, as it's grown as a commodity crop. Interestingly also grown in New Guinea (even though mostly different varieties).
Others are maybe forgotten, since they compared unfavourably with the new crops.

Razib recently unveiled a 3D model he adapted from Zack's Harappa Project that suggests a 3rd centre of recent population expansion in Eurasia, possibly aborted and partially "eaten up" by the other two. Maybe there was a lack of local suitable native plants and the resulting less competitive crops lead to a semi-forager lifestyle. This would perhaps explain the absence of archaeological evidence.

Based on these indications I thought it would be fun to run a supervised ADMIXTURE analysis on East+South Asia.
I used a Fertile Crescent pole, consisting of Adygei+Turks+Palestinians. A Yellow River pole based on Beijing Chinese and Japanese. And a hypothetical 3rd Revolution pole based on Papuans and Melanesians, for lack of better "unadmixed" populations (even though I'd expect Papuans to be more of a fringe group and not exactly the Core Area population).
Here are the results.

The results correlate to a surprisingly high degree with the estimates by Reich and al as the table at Dienekes shows.


  1. FWIW, here is my take on ASI.

    1. The age of the South Asian Neolithic corrolates closely with the linguistically estimated time and place of origin of Dravidian.

    2. The only significant non-South Asian uniparental marker in Dravidian populations is Y-DNA haplogroup T, which is present in high percentages very close to the proto-Dravidian area and rare at the Dravidian fringe.

    3. The crops and cultivation methods associated with the South Asian Neolithic are mostly those of the African Sahel farmers and many are clearly African domesticates. There are also significant significant signs of cultural borrowing from African Sahel farmers.

    4. There is little crop overlap between the South Asian Neolithic and either Harappan crops or East Asian domesticates, and the archaeology supports fairly weak trade links between the Harappans and the South Asian Neolithic culture. This makes sense, as Dravidian areas of India are ill suited to Fertile Cresent crops (providing a natural boundary to Harappan expansion) and better suited to African Sahel crops (facilitating Dravidian expansion when those crops arrive).


    1. The South Asian Neolithic was a cultural transfer from Sahel Africa by a male dominated, haplogroup T heavy population that did not completely replace local populations but had disproportionate cultural influence and genetic component in the initial expansion in the proto-Dravidan area, but this language and lifestyle was carried beyond the area it first took off culturally rather than demically, or by unadmixed native populations. The identity of this population is not entirely clear as Y-DNA haplogroup T outside India is not an easy match to history, and Sahel farming took place at the Southern fringe of its distribution. But, the timing has to be a close fit to the South Asian Neolithic/proto-Dravidian date which is about 1000 years pre-South Asian Indo-Aryan.

    2. ASI is the mark of the small South Asian population at the core of the Dravidian/South Asian Neolithic population that expanded demically to fill much of South Asia, and the proto-Dravidian language is what prevailed in this community at the time that it started to expand - largely extinguishing other pre-Dravidian languages and muting the pre-existing population genetic signature relative to proto-Dravidian population genetics. Their expansion is an important reason that the South Asian/East Asian population genetic divide is so stark - East Asian tied genetic populations would have been further North from the proto-Dravidian area.

  2. I wonder if South Indian agriculture could have an East African origin. A common ancient substrate of linguistic traits is shared by most of the languages of South Asian regardless of linguistic family. Many of these traits extend northward in Central Asia and some appear in East Africa (my source is "Defining a linguistic area" by Colin P. Masica.). Perhaps, agriculture reached southern India from East African along with these linguistic traits.

  3. What do you mean "South Asian Neolithic" North India or South India? North India had FC crops. South India is poorly documented...
    "Age of Neolithic" generally means introduction of more advanced agriculture. Evidence of primitive sporadic agriculture from thousands of years ago is probably very difficult to find archaeologically.
    Dravidian in my view is a Fertile Crescent derived language, maybe connected with Elamite. It is also spoken by isolated groups in North India, most likely adopted Kurgan-culture-derived tongues later.

    It is intriguing that we seem to have three full fledged Neolithic revolutions in the Old World: East Asian (Yellow River), West Eurasian (Fertile Crescent) and West African. I personally think South Asian and East African resilience against the onslaught of the former has likely to do with incipient Neolithic revolutions among peoples still practising some foraging.
    I don't know if there's any connection between the two, but it seems very improbable. I do know there are some haplogroup connections, but these have tended to be ascribed to the far past.

    Some connections between Indian and African agriculture can be explained by other phenomena. Some tropical crops cultivated in both India and Africa may have to do with the introduction of the African ancestors of Makrani by slavers much later. Slaves with a major agricultural advantage (new better crops) are likely to thrive somewhat and introduce new crops, even in an alien Malthusian society.