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There has, of late, been a veritable tsunami of results from recent research that are literally transforming prehistory before our very eyes. One of these that has attracted a lot of interest beyond specialists in early Southeast Asia comes from Óc Eo, a 2,000-year old port on the Mekong Delta. It was first excavated by the French archaeologist Louis Malleret during the Second World War, and in his voluminous publication, he described a rectangular, moated city divided into wards by canals that radiated out across the flat delta landscape, linking Óc Eo with Angkor Borei, the probable capital of an early kingdom known to us from early Chinese visitors as Funan. This city was a vital node in a trading network, known as the Maritime Silk Road, that brought Chinese mirrors and ceramics, Indian-inspired religions, temples, and script, even Iranian and Roman coins. Now we have a new trade item straight from an Indian cookery book. An examination of stone mortars has identified starch grains, the list comprehensively covering the components of South Asian cuisine. Turmeric probably came from India and cloves from the Molucca Islands. Cinnamon is native to Sri Lanka. Other spices include ginger and galangal. Mix them up and you have curry powder. This finding needs to be taken in conjunction with the DNA from a young man from an Iron Age cemetery at Angkor Borei, dated to the 1st to 2nd century AD, that revealed 42-45% South Asian ancestry.
The subject of ancient DNA brings me to another paper published recently that, behind its direct and factual text, has seismic implications for prehistory. Just three years after Crick and Watson walked the few yards from the Cavendish Laboratory in Cambridge to the Eagle pub to announce the structure of the double helix, I found myself passing through a tiny French village, Gurgy-les-Noisats, on my moped en route to a summer spent digging at Arcy-sur-Cure. Renowned for its hazelnuts, this village should now be better known for its Middle Neolithic cemetery, dated between 4850 BC and 4500 BC. Excavations there have progressively uncovered a cemetery of 128 inhumation burials in which barely one has disturbed another, a sure sign that the people knew where their ancestors were buried. On purely archaeological grounds, there is no pathway to finding out how long the site was in use, unless one radiocarbon dates an awful lot of bones, because there is no vertical stratigraphy. Very few graves overlie another. Only a decade or so ago, this site would barely have registered any interest beyond the Department of Yonne, for grave goods were sparse and there was nothing very much to report.
Secrets from the grave
However, 110 individuals were sampled for surviving DNA, of which 94 returned positive results. Strontium 87Sr/86Sr ratios were also obtained for 57 individuals, in order to distinguish between those raised locally and others who joined the community from a different environment. The increasing incisiveness of DNA analyses in identifying relationships has sorted the cemetery population at Gurgy into two pedigrees or descent groups. The larger, Group A, comprises 44 males and 20 females, while Group B contains seven females and five males. The former group has resolved into seven generations, in which descent followed the male line. Here is evidence for a patrilineal and patrilocal social order, while, at a stroke, the duration of the site has been identified. The founding father was found as a handful of bones, reinterred from elsewhere it seems, in the grave containing a complete female skeleton who, unfortunately, did not yield any DNA. Thereafter the graves of the succeeding six generations extended out from the founding father in a south-westerly direction. The graves of Group B, meanwhile, concentrated in the northern sector of the burial ground.
When looking in detail at the female genomic data, we find that none had a parent or other ancestor buried at Gurgy. So they must have been newcomers into the community, most likely as marriage partners. A clinching point for this hypothesis is that there is a great diversity in mitochondrial DNA across the women at the site, suggesting that they originated in multiple other groups. Moreover, there are no half siblings at all. Marital relationships were, it seems, stable. Perhaps, too, the females born at Gurgy left it for marriage elsewhere, as the ratio of locally born men to women is 4.5:1, there being 27 men and just six women. Compare this with the sex ratio for those who died when too young for marriage, most of them under eight years of age, and we find it normal: 19 boys and 18 girls.
One way of testing for female mobility is through the analysis of the strontium isotopes as indicators of diet, and therefore the locale where a person grew up. The results are fascinating. The men and girls cluster together, in contrast to the adult women, who seem to have originated elsewhere.
When examining the age structure of Group A, we find that, for the first four of seven generations, only five subadults of 36 individuals were buried at Gurgy, whereas this figure reverses for the last three generations, when 20 of 25 were subadult. What does this tell us about social mobility and behaviour? The most parsimonious interpretation is that members of several generations moved to the settlement responsible for this burial ground, leaving behind, as they departed, the graves of their deceased children. Then, for the last three generations, the parents moved elsewhere, leaving behind the graves of their children. But one person stood apart, the re-buried few bones of the founding patriarch. When you factor in the suggested arrival and departure of, say, two generations at once, the duration of the seven-generation cemetery was probably only about a century, if you give 28 years to a generation. This conforms with the radiocarbon chronology, and the estimated durability of a well-maintained Neolithic longhouse, or the sustainability of successful farming through the methods then practised before soil degradation set in. So it all makes sense. I do wonder what my teachers way back would make of insights such as these.
As I have mentioned before in this column, I have for years had to encounter the frustration that DNA does not survive well in the hot and wet climate where I dig in Southeast Asia. And this frustration gathers momentum when I reflect on what I found at Khok Phanom Di. Commanding the estuary of the Bang Pakong River, this Neolithic community lived continuously for at least five centuries, adapting to the changing environment as the sea level fell back, and then rose up again. The tropical estuary is one of the richest habitats on earth, and the diet included crabs, fish, shellfish, and rice. There, we don’t find seven generations, but between 17 and 20. And, unlike Gurgy-les-Noisats, the dead were buried in tight groups on top of the ancestors, so as to keep pace with the dying, because the site accumulated at such a rapid rate. As at Gurgy, all graves were intact, meaning the location of the ancestors was clearly well known. When Ron Pinhasi found that DNA survives particularly well in the petrous bone, son Tom and I went to the archived skeletons and sampled this dense bone in the hope of our own eureka breakthrough. However, of more than a hundred individuals sampled, just one has yielded DNA. So, in trying to glimpse into the relationships between the successive generations, we have turned to genetically inherited markers in the teeth, such as a cingulum or Carabelli’s cusp. And what we found was fascinating. Like Gurgy, we identified two particularly enduring putative lineages, and each displayed these inherited quirks through successive generations. Moreover, Alex Bentley’s analysis of the strontium isotopes has identified two pulses when people came to the site from elsewhere, the first with initial settlement and the second halfway through the sequence, when some women came to the site from a different habitat.
I had nearly given up hope of ever making the DNA-style breakthrough seen at Gurgy, when Eske Willerslev and Hugh McColl began sending me emails about the people of Iron Age Non Ban Jak from their DNA lab in Copenhagen. I know I have recently recounted this news, but it bears repeating. There, we returned season after season to trace and record house plans. We found stout walls and floors, kilns, houses destroyed by fire, and even a kitchen with a pot still on the stove. Vitally, we also found that the dead were buried inside these houses, in graves cut through the floors. The emails reported a growing number of positive hits for ancient DNA, and now, as these are being digested in Copenhagen, we stand on the brink of ‘doing a Gurgy’ and really entering the brave new world of palaeogenetics and prehistoric social lives once thought to be beyond the bounds of possibility.
Charles Higham is a Professor at Otago University in New Zealand, and an authority on Cambodia's Angkor civilisation and Ban Non Wat in Thailand.
