Over the past few years I have cast a skeptical eye at human phylogeography. Researchers like Spencer Wells have parlayed the study of uniparental lineages into books and television specials. Taking gene trees constructed from the Y chromosome Wells fashions the story of our species, in particular, of men. The problem of course is that Wells is looking at the lineage of the Y chromosome only! Humans are not neat little vacuum packages, nor are populations, rather, we are messy amalgamations of discrete genetic coalitions which are always in flux. Primed by our cultural mythologies and likely our mental biases we jump at neat and simple narratives, and in this day and age a scientific patina only makes it all the more sweeter. But we live in the post-genomic era, and as more and more data begins to push its way to the table I suspect that a readjustment of our plain yarns is inevitable.
But not all of human phylogeography is worthless, one has to pick one's battles. Consider the recent work investigating the genetic impact of the Anglo-Saxon migrations. Or, consider this paper, Balinese Y-chromosome perspective on the peopling of Indonesia: genetic contributions from pre-neolithic hunter-gatherers, Austronesian farmers, and Indian traders (full PDF). The authors found that a little more than 10% of the Balinese Y chromosomes seem to be Indian in origin. This is important, Bali is the last major refuge of Southeast Asian Hinduism. The historical mythologies of the pre-Islamic Hindu-Buddhist kingdoms of Austronesia imply that there was an emigration of notables from the kingdoms of southern India, particular from what is today Tamil Nadu, which reshaped the cultural landscape of the region. India and Bali are geographically distinct enough that the signal of exogenous lineages should be detectable, and it seems they are. Additionally, Bali is an island, which minimizes the possibilities for continuous genetic exchange with surrounding populations. Finally, we know the vague outlines of Bali's history, so that we can bring to bear other disciplines to fine tune our probabilities of plausibility.
Whether South Asians influenced Bali genetically as well as culturally is not as grand a question as "where does our species come from?" But, it is modest enough and narrow enough that one can imagine a testable hypothesis. Unlike the origins of our species the history of Bali is somewhat illuminated by its own written records & mythologies, we are not flying in the dark relying on DNA only. The objective is tenable, and the tools are at our disposal are variegated and diverse.
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GREAT post. Course, being south indian, and having an interest in the diaspora to south east asia, i'm slightly biased. Still...
I read some reports from the 70's that south indians shared up to 30% of their DNA with africans. Unfortunately I only briefly looked at the abstracts because I was in the middle of doing monkey research. But it was American Journal of Physical Anthropology.
You heard anything of the sort?
You heard anything of the sort?
sort of. i believe hammer et. al. did some mtDNA work on some andhara pradesh populations which showed some affinities (genetic distance) with sub-saharan africans vis-a-vis other eurasians. i don't think this has panned out...sample size matters, and mtDNA is subject to stuff like genomic convergence...and well, to some extent everyone is a subset of africans in many mtDNA phylogenies so it makes sense everyone would share genes with africans.
i tend to be of the opinion that south asians are a distinct and coherent phylogeographic unit, as opposed to being a simple subset of west eurasians (as the standard perception would imply). there is after all the 'indigenous' substram which shows ancient affinities with eastern eurasia, and in northeastern india, including bengal, there are more recent associations with eastern eurasia (e.g., if you look at the mtDNA clades eastern india tends to align with eastern eurasia, western india more with western eurasia). in the real eve stephen oppenheimer argues that india is the source of most eurasian lineages, that is, it was the first big stop outside of africa, so that could explain why indians might cluster with africans, as they are the more reflective of the ur-diversity in the original homeland.
anyway, itz complicated :) if you are curious about exploring the brown archeogenetic lit, start with this paper, and work through the cites.
cool, much appreciated. I didn't want to put much stock in a 1970's paper. both physical and cultural anth were more or less completely hijacked by politics at that point.
The mtDNA of Eurasia is divided into East Eurasian, West Eurasian and South Asian, but sometimes it overlaps. A large part of SA mtDNA is composed of Indian specific M and R haplogroups like most Non-African; however M haplogroups are missing from the Middle East and Europe, I wonder why? From what I've read the distinct SA mtDNA is partially the result of geographic barriers like the Himalayas, the Thar+ Iranian deserts.
Here is something:
"Proponents of the southern dispersal route have argued for a rapid initial dispersal around the South Asian coastline (e.g., Oppenheimer 2003), but the mitochondrial DNA evidence suggests expansions of modern human populations within South Asia close to its initial colonization (Kivisild et al. 1999b, Metspalu et al. 2004). A further demographic expansion is suggested by the coalescence of a number of India-specific M lineages to 20,000 30,000 years ago (Kivisild et al. 1999b, Metspalu et al. 2004) and may be related to other demographic expansions within the Old World and the more stable climate of oxygen isotope stage 3 (Forster 2004). Intriguingly, recent work has indicated a genetic continuum between the Near East and India coalescence-dated to between 50,000 and 30,000 years ago. By 20,000 years ago the window of this continuum had closed, perhaps representing the isolation of populations due to the increased aridity of western India and Iran as the Last Glacial Maximum approached (Metspalu et al. 2004)"
Wells deserves big time credit for his data gathering in Central Asia that led to the "Eurasian Heartland" paper. His popular-audience books and Genographic Project have fueled interest in this subject, which can be turned into research funds.
This field still suffers from a major lack of data. Nobody can even yet agree on basic where R1a finds a maximum of diversity, is probably much younger than some of the mtDNA clades lurking out there.
Isn't it interesting that there were many waves of immigration into India (mostly from the North-West), but the only emigration that I know of is to the South-East?
Actually, China has a similar pattern.
Ancient India (including Sri Lanka) did have a trade relationship with East Africa. I think that was one of the reasons (along with our cosmetic similarity) for htinking that perhaps there was a large amount of east african dna in southern populations.
I coudln't tell you how far that trade relationship went, whether there was much of an Indian trading community actually based in east africa or vice versa, because Indians can suck at studying the specifics of our history.
Ancient India (including Sri Lanka) did have a trade relationship with East Africa. I think that was one of the reasons (along with our cosmetic similarity) for htinking that perhaps there was a large amount of east african dna in southern populations.
I wonder about any genetic influence of Western Eurasians or Eastern Africans even in male lineages. I think it is worth noticing that Indian caste population largely lacks E3a, E3b, I, R1b.
As far as I know, South Indian male lineages are just subset of North Indian lineages.