All Hail Svante Pääbo
Over the last ten years, this magazine has reported from time to time on the advances that were being made by researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, in the replication and mapping of ancient DNA, a process that even 15 years ago was considered impossible. Thankfully, Professor Svante Pääbo, Director of the Department of Genetics at the Max Planck Institute team studying our Neanderthal cousins as well as the previously unknown Denisova hominin, refused to accept such a defeatist attitude and he has just been awarded a Nobel Prize for his work in this field.
The prize is for Physiology and Medicine, and Pääbo is described as a geneticist, but we have every right to claim him as an archaeologist because his work is not purely biochemical: it has advanced our knowledge of Neanderthal culture as well, not least the discovery that modern humans of Eurasian descent have inherited parts of the Neanderthal genome (and vice versa: there is now evidence from Neanderthal remains from Siberia, Croatia, and Spain of human gene flow into the Neanderthal genome). Such discoveries have led us to reappraise our understanding of Neanderthals and reinterpret the associated archaeological evidence – the tools, the burial rites, the use of ochre – to realise that our two species were much closer than was once thought and that Neanderthals were much more like us in appearance, behaviour, social organisation, and the capacity for abstract thought and creative activity.
Archaeologists have adopted the extraction and analysis of aDNA from humans, from animals, and from plant material and food remains with alacrity. In a very short period of time, we have mapped aspects of human migration that were previously in question – how much do the innovations of farming, pottery use, and metalworking represent the movement of people and how much the transmission of ideas? The answer is surely both, but with a much bigger role for migration and movement than we might have been prepared to accept in recent decades.
Our sister magazine, Current Archaeology, devoted a whole issue last month to the results from aDNA analysis based on human remains from early medieval cemeteries in England. This shows that a much larger proportion of the population of the period from the 4th to the 8th centuries had continental North European ancestry (deriving from the modern Netherlands, north Germany, Denmark, and southern Sweden) than had been acknowledged in the recent past. England was no exception to the history of migration and movement that characterised this period all over Europe and Asia, and there is surely a great deal more to be learned about the very topical subject of migration from future aDNA studies and the associated science of bone and tooth isotope analysis.
These discoveries have also focused attention on past mobility. We tend to think that modern humans are highly mobile and that long-distance travel began in the 1840s with the railway age, but we now know that humans have always been travellers and that the movement of peoples has had a major impact on history, whether the peopling of the globe through migration out of Africa to Australia and the Americas, or the recent discovery that horse-born people of the central Asian steppe had a considerable impact on the genetic makeup of Bronze Age European populations, or the extensive trade networks that supported the distribution of copper, tin, silver, gold, precious stones, spices, and silk in the past.
It is a very exciting time in archaeology, characterised by a flood of new discoveries that change our core paradigms on an almost daily basis, and it is good that Svante Pääbo’s contribution to modern science-based archaeology has been recognised. Interestingly, Svante is the second member of his family to be elected a Nobel laureate: his father, Sune Bergström (1916-2004) shared the same Nobel Prize in Physiology and Medicine in 1982. Is there a gene, one wonders, for Nobel-Prize-winning science?
The everyday diet of Neolithic people
At Bristol University, researchers have been specialising in the analysis of food residues on the surface and in the walls of absorbent ceramic vessels dating from the early Neolithic, when people first started consuming domesticated animals and crops. Cows, goats, and sheep, it appears, were reared primarily for their milk, which was added to grains to create nutritious and filling wheat-based porridge.
Until now, it has not been possible to distinguish between different cereals, but the Bristol team, led by Drs Simon Hammann and Lucy Cramp, has developed the means of detecting the molecular traces of different types of grain, and they say that previous studies have underestimated the importance of wheat, mainly because the evidence from charred plants has pointed to barley as the staple grain – the process of charring having the effect of helping to preserve the grain against fungal and microbial attack.
With porridge as the basis for the everyday diet, meat was reserved for special occasions, just as now in many parts of the world. At Durrington Walls, where the builders of Stonehenge probably lived, large feasts were held in midwinter, and a study of the bones from food pits at the site shows that participants roasted and consumed ten times as many pigs as cattle.
Pottery residues from the site also have high quantities of pig-fat residues, despite bone evidence showing that the meat was roasted on a spit rather than cooked in pots. Noting that the pig-fat residues are found in vessels that resemble buckets rather than dishes for cooking or serving food, Dr Lisa-Marie Shillito, Senior Lecturer in Landscape Archaeology at Newcastle University, has concluded that the vessels were used for collecting and storing pig fat. Tallow lamps are most often made of beef or mutton fat, so was there another use for the pig fat? Dr Shillito wonders whether it was used to grease the runners on the sleds that transported the massive stones used in the construction of Stonehenge.
Heritage professionals are coming up with some ingenious ideas for helping people cope with the summer heatwaves that we have witnessed increasingly this century. In Britain, maps are being created of cool and shaded places where people can take refuge when temperatures are high, including many churches and cathedrals where historic buildings considered problematic to heat are coming into their own as cool places in summer.
In Naples, the city’s ancient water networks are being mapped and assessed for their ability to be brought back into use as an answer to global warming. The city has one of the most extensive water systems in the world, fed by aqueducts dating from the Roman period, such as the Aqua Augusta. Built in 30 to 40 BC, this extensive regional network brought water from mountain springs to at least eight ancient cities in the Bay of Naples, including Pompeii and Herculaneum. At various times in the past, engineers have asked whether the Roman system could be brought back into use, and the Cool City Project, a collaboration between scientists in Italy and the United States, is using high-tech survey equipment to map the underground tunnels and lost water channels.
Some of these tunnels are massive enough to form potential retreats for people most at risk, but other uses might be to reintroduce fountains to the city or to use the water to irrigate green spaces with shade-creating trees that will act as cooling agents to offset the heat absorbed by and re-emitted by buildings.
Meanwhile, the Cool Towns alliance is bringing together 14 European partners to seek ways of counteracting the negative effects of climate change and find attractive solutions that are less vulnerable to heat stress. With rising sea levels threatening coastal and riverine cities, we might learn much from the centuries of experience that the Netherlands has in water management. Could London and New York become more like Amsterdam or Venice, with road systems converted to networks of newly created canals to contain excess water? Given the amount of archaeology that survives below city streets, it would be good to think that a canal-building programme might be preceded by a major archaeological effort, but realism suggests that archaeology would be sacrificed to the need for a rapid flood-mitigation solution.