When STRUCTURE-style bar plots first emerged using the HGDP Cambodian samples, there were often strange residual components with affinities to South Asians. When Treemix was developed there were strange edges between South Asians and Cambodians. In discussions with Joe Pickrell, the author of Treemix, we both adduced this must be due to deep affinities to “Ancestral South Indians” (ASI). Though Cambodia had “Indic” cultural affinities, the standard model is that this was due to cultural diffusion, not gene flow. Then Spencer Wells told me that The Genographic Project had detected that many Cambodian males seem to carry the R1a1a lineage. Looking at the literature, several Southeast Asian groups carry West/South Eurasian haplogroups which are likey Indian-mediated (R1a, R2, and J2, to name three). The enrichment is notable in groups like the Thai and Khmer which are located at some distance from South Asia.
Out of curiosity, I decided to look at the “Cambodian Iron Age” sample from a recent ancient DNA paper. This sample dates to 100 to 300 A.D., the period of ancient Funan, which we know mostly though not exclusively through Chinese sources:
According to modern scholars drawing primarily on Chinese literary sources, a foreigner named “Huntian” [pinyin: Hùntián] established the Kingdom of Funan around the 1st century CE in the Mekong Delta of southern Vietnam. Archeological evidence shows that extensive human settlement in the region may go back as far as the 4th century BCE. Though treated by Chinese historians as a single unified empire, according to some modern scholars Funan may have been a collection of city-states that sometimes warred with one another and at other times constituted a political unity.
Look at the Iron Age sample it does seem it is notably “Indian-shifted” even compared to modern Cambodians. This could just be an artifact of ancient DNA, but when I looked at a few dozen ancient Vietnamese samples, only one exhibited this same pattern of being Indian-shifted. Reducing the dataset to the 55,000 SNPs that came back on this ancient sample, you see the result above (many of the modern samples don’t have the full complement of these SNPs).
Something on the order of ~5-10% of the ancestry of many Southeast Asian groups seems to be of Indian origin. Looking at the Malays in the Singapore Genome Project, some of them have clear recent Indian ancestry, but even removing all of those you see notable Indian-shift, just as you see with the Cambodians. In contrast, Vietnamese and Dayaks from Borneo don’t show any evidence of such admixture. Neither do samples from the Phillippines.
The question is when this admixture occurred then. A large number of Indians migrated to Southeast Asia during the colonial period to Malaysia and Burma. But some preliminary analysis suggests to me that this doesn’t account for all of the Indian ancestry there. And, it can’t account for Cambodia and Thailand at all (though there aren’t too many genome-wide samples from Thais, the Y chromosomes show the same pattern as the Khmer).
Over time the genetic data is going to coalesce and converge on the details, though I think we see where it’s pointing. At that point, it’s up to archaeologists and historians to make sense of it. This includes scholars of South as well as Southeast Asia. The genetic imprint of South Asians in Iran and Central Asia is rather modest compared to what one sees in Southeast Asia, so it’s an interesting contrast as to why.
Travel to the west was more dangerous as you have to cross deserts but not so perilous journey to the east through land.
I could be wrong.
Homo is an expansive and competetive species, that’s its formular for success. All major expansions of the past were caused by differing levels, like if you have two waters, the one with the higher water level will always flow in the one with the lower. There will be backflow quite often, but generally, that’s the rule.
There are three main causes for advantages one group can have over another, and most of the time they will be intermingled:
– genetic
– cultural
– demographic
Indo-Aryans and Dravidians developed rice farming high cultures which expanded into the more tropical South, but these cultures were made for moving deeper and deeper into a new colonial territory, while at the same time moving away from the North Western conditions from which both ethnic unities came from. So they became more competitive for the South Eastern direction, but not much more or even less for the North Western one. And usually, humans always take the path of the least resistance. The competitors in the North West were strong and hard to defeat, the South East was, after the rice culture revolution, like one soft cake to be cut into pieces for the first to come. The same was true for the Sino-Tibetans, Tai-Kadai, Austroasiatics, Austronesians in the East.
South East Asia was the Wild West for all these more developed people from East and South Asia, with one wave after another moving in and competing for the best spots. That’s why Vietnam shows less of the Indian component: That was East Asian expansion territory, so no soft mass of jungles and wildlings to be taken like a ripe fruit, but hard to fought for. The Vietnamese proved to be a very hard nut to crack over the centuries to come, so no wonder.
The real question is why the South Asian gene flow was so low and the reason is the natural borderline of swamps and dense forests. So most of the movements will have happened when the Eastern front was already more developed by the (new, already farming) locals and/or there were major sea routes established.
This meant the East Asian expansion was easier to make and demographically much more successful in SEA. Little mass movements, but rather trade and elite, only smaller settler groups most likely. But with still a significant impact because they founded more developed, successful cultural groups which expanded demographically after the influence from West.
The competitors in the North West were strong and hard to defeat, the South East was, after the rice culture revolution, like one soft cake to be cut into pieces for the first to come. The same was true for the Sino-Tibetans, Tai-Kadai, Austroasiatics, Austronesians in the East.
the s. asian flow is AFTER all of the above.
i think the flow is probably due to sea, not land, fwiw.
(re: vietnam, the southern 2/3 of the country is recent conquest and demographic expansion from chams and khmers)
I know it was afterwards and the history of Vietnam and that they colonised the South. The Indian influence in South East Asia would have been much stronger without the later incursions from the North, the conquests of the Vietnamese and Thai for example. The Mon-Khmer people are obviously the older layer and their replacement went on in historical times. Though one can question how much of this was demographic replacement, because of many farmers being just down the social ladder. In Vietnam however, we can speak of a replacement of the local people.
So in already historical times we have competing groups which were more South or East Asian respectively and as a rule, the East Asian (like Burmese, Thai and Vietnamese) won. Like the end of various Khmer realms and the destruction by the Thai is really a historical event. But the Thai were an elite conquest movement for most of the time. Clearly we have Indian influences on the Khmer before that. The Khmer kingdom as it was is unthinkable without Indian influences.
So there will be different time windows for different Indian influences (during the formation of the Khmer kingdoms, after their destruction, in Thai kingdoms and in colonial times for example).
But another question is the basic layer predating more recent East and South Asian migrations, being related to AASI. I mean R1a and J1 are clearly Caucasoid markers, but what about more ancient relationships of the original forager population and how to differentiate these two elements in modern South East Asians?
hoabinhian distantly related to AASI. onge more close to hoabinhian
I am not sure if it’s accurate to suggest that the genetic outflow from South Asia towards Iran and Central Asia is quite limited compared to its impact in SE Asia.
From what I can remember, there is about 5 to 10 % AASI (old ASI) admixture in most modern Iranians and Central Asians including that of Uighurs.
Considering the fact that this genetic admixture would have mostly come from Northwestern South Asians who themselves have only 20-30 % AASI at present and may have had even lower AASI as inferred from Indus Periphery samples, this could easily mean around 20 % and more admixture into Iran and Central Asia from NW South Asia.
Ofcourse, majority of the ancestry in NW South Asians & Iranians and Central Asians is of the Iranian Farmer/Hunter Gatherer type which is deeply shared between these regions. As a result, the scale of more recent admixtures between these regions is difficult to estimate.
I think Jaydeepsindh may have a good point (lower South Asia ASI ancestry may mask similar demographic impact of people from somewhere in South Asia, despite lower ASI in Central Asia than SE Asia), although I guess there’d still be a gap if his explanation was accounted for. With that in mind I’ll try an explanation:
On more demic impact of S Asia on SE Asia than Central Asia, I’d guess it’s (not perfectly) analogous to the greater impact of the Ashkenazi Jewish demographic expansion in Eastern Europe, than Western Europe.
These people (as far as we know?) in SE Asia came as traders and religious specialists, filling a new urban (or para-urban) niche, and got in at the ground floor when there was plenty of scope for urban expansion. In Central Asia, the urban routes and trade were already well established and policed by other groups and usually dominated by “natives”.
Just as Ashkenazi Jews were more “in at the ground floor” of urban expansion in Eastern Europe than Western Europe and Northwestern Europe than Southwestern Europe. Possibly the advantage was being the specialists who were able to fill a new and complimentary niche, just when that niche was expanding, not competitive superiority in the same specializations and niche.
As far as we know in SE Asia these people didn’t come as conquerors, and may not have got far if they had done, unless they had put serious technological and demographic advantages (for ex, the superior aasabiyah of peoples beyond the frontier of the core, where cooperation it is broken down over time and all that Ibn Khaldun stuff on why the Arabs from the periphery conquered the core and so on).
Really I think its all about timing, when the AASI spread, or better survived and I think this layer is pretty old, in any case much older than the SEA expansion and there was no massive expansion South -> North.
@Matt: “As far as we know in SE Asia these people didn’t come as conquerors, and may not have got far if they had done, unless they had put serious technological and demographic advantage”
That’s not entirely true, because there were presumably Indian conquerors in South East Asia, almost like conquistadores probably, and they brought advanced metallurgy and horses with them among other things. So there were these traders coming by sea, but there were also conquerors, coming by sea too. And the conquerors might even have had a greater demographic impact, especially if talking about the results 2000 BP. I don’t know whether the new tests looked for social status, but I really doubt that the R1a and J2 carriers which would pop up were at the bottom of the Cambodian social ladder.
The original warrior colonialism survived in legends like the one of Kaundinya:
https://en.wikipedia.org/wiki/Queen_Soma
Later historical accounts reported riders and war chariots in Cambodia and we have the Indian legends, style and scripts among many other things in Angkor Wat. The Indian influence is very strong on the whole Cambodian culture and it seems to have been rather elite transmitted. Similar to later Thai influences which brought elements, genetic and cultural, from Central and Southern China to the region, just even more sweeping – like the Burmese too, whereas the Vietnamese are the most interesting case, because they Austroasiatic layer not just resisted, but incorporated the later Sinitic settlement and became a major player itself.
Cambodia asked for protection from the Thai by France and Cambodia is another case of a stopped/slowed down replacement process by European colonialism. It would have been torn into pieces by its stronger neighbours in meantime for sure.
What is left of the once mighty Cham people (they were the main competitors of the Cambodians in the region for quite some time) Razib mentioned before speaks for itself.
I don’t know if there is any evidence that horses or metallurgical techniques came to SE Asia via S Asia as a primary, new introduction. Certainly these things could and did come via Central Asia via Tibet and also via China (cf blench – http://www.rogerblench.info/Ethnoscience/Animals/Livestock/The%20horse%20in%20SE%20Asia.pdf). Legends will often reinterpret things that happened via the current cultural tradition so are a fairly flimsy basis. Indeed I am not sure if there is any prominent archaeological opinion supporting any primary (first) metallurgical technology dispersals from South Asia into SE Asia.
(It looks like today at least, we do have a good idea that the source of South Asian ancestry in Cambodia, Burma and Thailand is fairly heavily ASI, looks roughly as much so as Bangladesh / Chamar. This seems to be the case in ancients too? So if any “warrior colonialism” at 2000 YBP did come it would either be associated with such people, had very low impact, or did not survive.).
It had no big long term impact presumably because of a small elite group as founders and the competition with other elites and the sweeping expansions of the mentioned people, for Cambodians especially the Thai which really rolled over them. Its like a miracle they stayed alive at all, caused by their puffer position.
The Indian conquerors had competitors from the Eastern steppe for sure, but they were among the first and most influential ones for the Western part of SEA, Funan/Cambodia.
Its remarkable how many groups tried to get their piece of the region, even Japanese and Turkic related groups made it there.
I guess the early Indian influenced elite of Cambodia will show the highest Indian (proper, not AASI-like) scores and I doubt that will be surpassed by any later samples which will just document the East Asian replacement from China mainly with some Indian and steppe ancestry being thrown in here or there.
That like in the newest post Thai had no East Asian first is clear, because that was a brutal ethnic conquest at first. Just later the Thai took slaves, workers and allies from the surrounding, surviving locals, from the refuges.
They integrated them in their system until many of the modern Thai became more Cambodian than old Thai (=~ Southern Chinese like).
Similar to the Indo-Aryan conquest in some parts of India.
Even following the legends, a few males marrying local SEA women founded the Indic Cambodia. So what mainly survived after some generations should be the y-chromosome. That’s what matters in this case the most, like so often.
@Matt: Also look at the article of Blench point #5: Sanskrit/Pali roots in Mon-Khmer languages. So if anything this linguistic overview gives support to my position.
The archaeological evidence so far proves little to nothing. But I’m not even saying Indian founders would have needed the horse to succeed, they had enough assets. But I would consider its presence as an option.
Blench pretty much reports the standard traders and missionaries story (“The second likely route into SE Asia for the horse is early contact with Indic peoples. The horse is strongly associated with the entry of Indo-Aryan peoples into India, and as Indian mariners and missionaries spread out in SE Asia, they carried both actual horses but also ideas about the religious significance of the horse. The exact beginning date for the process of Indianisation in mainland SE Asia remains disputed, but it is now thought that Indian ships were seeking commercial routes as early as the second century BC” … Comparative lexical data shows that the most important source of horses on mainland SE Asia is China… Horses and horse imagery are also brought separately through Indian contact, both along maritime routes but apparently through contact with NE India. The early iconography of the horse in SE Asia can be misleading, since much of the imagery refers to stereotyped Indian mythological scenes. ). I don’t think there is anything in there that specifically supports any “Indian conquerors” of SEA type of ideas over dissemination of terminology through religion, etc.
Migration from India to SE Asia may be male biased either way and more visible in the y chromosome, but that doesn’t say anything much about why or how people came (Ashkenazi Jews and Peranakan Straits Chinese were both formed by male biased movements and local women… by traders, merchants).
Ashkenazi Jews and Peranakan Chinese didn’t found empires on their own though. There were Chinese or Sino-Tibetan founded tribes and states though, which were based on the same principles. So its not the Chinese didn’t do it…
The Indian adventurers in Cambodia did it successfully. I know the evidence is in large parts circumstantial, but all we have points to some sort of conqueror, warrior group making a local alliance or putting themselves on top of one or more local groups and expanding on the base of this new, more developed cultural units, proto-states, into wider territories. Most likely they kept contact with home, via traders and priests etc., but the main difference to the Spanish in America is, that they had no constant supply or dependency from states at home. They did their own thing in Funan.
Since they were not numerous enough, nor dependent from their mother country, and their sons were mixed and many local allies might have supported them, they didn’t completely change the people, but just brought them the higher culture from India and their leadership. Contrary to Thai, to stress this once more, which really rolled over the local people first and after establishing their rule by force, taking in local women, working force and allies to expand on.
The Indian adventurers and conquerors might have allied up from the start, but looking at the construct they created, they used force too for sure to expand and build an empire. Like in many other such cases, just wait for more ancient DNA, it will prove the social stratification and that local males were hunted more than once, with every new wave coming in. The territory is huge and has many hiding places though, and eventually many foes mixed afterwards. But usually the last dominant one formed the dominant culture and ethnicity, with the others joining at the lower social end of their system. With the exception of some local and regional elites which joined as allies.
Same in India as in South East Asia and everywhere else.
However, Ashkenazi Jews did form in Europe as a group (and reflecting real Levantine migration) at the same time as Hebrew principles of religion became the dominant influence in politics and in the form of high culture, and local kings reinterpreted themselves in terms as being successors of David, Israel, Biblical kings and so on. But it would be a mistake if a couple of thousand years later we thought this was from a few Hebrew conquerors who built new states on Hebrew models, “taking local women by force”, that then disappeared as an influence in the population.
Ultimately, I don’t tend to think that you actually had at all much founding of states by people from India (perhaps a few trading posts and whatnot), through military adventurism or what have you, along a European colonial model, and what seems like the more consensual narrative that Indian missionaries and mariners simply provided narrative cloth and luxury art for local state building that was already underway, is probably correct. Same thing probably happened with Islamic mariners again in insular SE Asia, and Buddhists in Central Asia neither reflected a conquering North Indian force. It is possible that adna will correct this in some form, but this will need careful interpretation.
The data will have the last word, that’s for sure. But the if you look at Cambodia, the influences are too big and complete, that’s more than just “influence”, that was build on purpose. And I’m not saying they fought against everybody there, because even the Spanish Conquistadores wouldn’t have succeeded against the Azteks without support from the local population. Rather they came in as a foreign, new force, with new, highly attractive tools and concepts. They might have convinced some, allied up with others and killed another people in battle if necessary. These Indian adventurers came in as a new player in a backward country and turned everything upside down. Also, look at the DNA evidence available already, the R1a and J2 in the respective regions, after all those later incoming people, speaks for itself.
Wait and see what comes up next 🙂