- MD
Sidestep: Is Ancient DNA Research revealing new truths or falling into old traps?
The above article was in relation to the find of 36 Lapita skeletons at Teouma Bay on the island of Efate in the South Pacific nation of Vanuatu. Isotope analysis was performed on the excavated individuals to determine the characteristics of human migration in the Pacific during this time period. Researchers were able to analyze isotopes from 17 of the individuals. Subsequently, they found that four individuals had different isotope levels from the remaining 13. It is believed that these four individuals were immigrants, and in addition to having different isotope levels, they may have been different culturally as well.
There are two comments in the main article I wish to highlight under their respective chapters.
4. What Happened? - One longtime premise is that as these early humans spread out in all directions over the land, groups of them encountered places that struck their fancy, pitched their tents and more or less stayed “home” for the duration of prehistory. This is not just a pet theory of academic prehistorians but the natural way that human beings have tended, over the millenniums, to connect their identities to where they live. The ni-Vanuatu, for example, take for granted their eternal ties to the archipelago; their oral traditions ascribe their origins to some nonhuman feature of the landscape, their first ancestors having emerged from a stone, say, or a coconut tree. Non-indigenous people seek the same rootedness in consumer ancestry services like Ancestry.com, which declare that they’re “Spanish” or “Irish” or "Asian". Reich believes he has proved, to the contrary, that human history is marked not by stasis and purity but by movement and cross-pollination. People who live in a place today often bear no genetic resemblance to people who lived there thousands of years ago, so the idea that something in your blood makes you meaningfully Spanish is absurd.
10. The Archaeologists dilemma - She had reached the same conclusions upon examination of the cranial morphology of the exact same skulls, which she believed more closely resembled those of Asians than those of Papuans.
SUMMARY OF THE ARTICLE
What can genes tell us about who we are? Millions of people around the world have begun using consumer ancestry services like Ancestry.com in an attempt to peer into their personal origins and understand where they came from. Meanwhile, though, in a handful of elite genetics labs around the world, scientists have begun analyzing ancient DNA - which can now be extracted from skeletal remains that are thousands or even tens of thousands of years old - to ask, and try to answer, even more fundamental questions about the human past. In only the past few years, as a new report in The New York Times Magazine describes, this burgeoning science of “paleogenomics” has begun to offer surprising revisions to the story of humanity. But at the same time, this research has generated significant controversy, including among some of the archaeologists, anthropologists and other academics who have collaborated with geneticists on this work.
1. The study of ancient DNA has upended many of our assumptions about prehistoric times.
For decades, it was commonly believed that ancient communities tended to stay in one place — and thus didn’t mix very much with their neighbors. When a lab in Leipzig, Germany, sequenced the majority of a Neanderthal genome, in 2010, the scientists surprised just about everybody with the finding that humans and Neanderthals had actually interbred; we now know that most people, with the general exception of sub-Saharan Africans, can trace part of their genetic inheritance to our extinct cousins. As it turns out, we probably bear very little resemblance to human populations of ancient times. Most of these groups — to which researchers have given names like “Ancient North Eurasians” — disappeared as distinct populations as they mixed with other peoples they encountered. The idea of “pure” groups with identifiable “origins” has been largely reconsidered.
2. Many of the new findings say the same thing: that these groups mixed together in the process of great and previously unknown migrations.
For example, ancient DNA research seems to indicate that about 5,000 years ago, when Europe was populated with a mix of hunter-gatherer groups and early farmers, a group of outsiders suddenly arrived - nomadic herders from the Asian steppes - and within a relatively short time their own ancestry became prevalent. Sometimes these prehistoric migrations seemed to result in “admixture” between groups on an even footing. Other times, however, researchers describe population replacement” or “turnover” - the near-wholesale shift from one predominant ancestry to another. Contemporary Europeans owe a significant amount of their genetic inheritance to the incoming herders.
3. For peoples around the world today, these new theories about origin and migration can have destabilizing implications.
In the South Pacific nation of Vanuatu, a few thousand kilometers northeast of Australia, the national post issued stamps that commemorated the first settlers on their remote shores. In an artist’s recreation of the founding scene, the people were drawn to resemble the country’s modern inhabitants, an indigenous group called the ni-Vanuatu. Recent work with the region’s ancient DNA, however, has suggested that the original settlers were in fact the distant descendants of a group of migrants from East Asia - people who looked nothing like the contemporary ni-Vanuatu, whose ancestors are presumed to have arrived much later. Does the country need to re-imagine its origin story, down to its stamps?
4. Archaeologists have collaborated with geneticists on these academic papers, but many of them now worry that the papers are trafficking in some old, discredited ideas.
Many archaeologists feel as though they’ve been here before. For the first half of the twentieth century, archaeology tended to believe that large migrations of superior peoples shaped the landscape and culture of the ancient world. That idea was easily exploited by nationalists, eager to tell stories about their people’s glorious past; the Nazis, for example, seized on the ideas of Gustaf Kossinna, a German archaeologist whose work seemed to find evidence of the inherent superiority of the German people. In the early 1960s, a new generation of archaeologists came to question these grand historical narratives and the unwarranted assumptions that supported them. They turned away from simplistic stories about the distant past in favor of much more detailed attention to specific societal dynamics. Now, some worry that their geneticist colleagues are making similarly grand claims on the basis of a small number of samples.
5. And, as excited as many archaeologists are about all of the new data geneticists have produced, some feel that their own concerns and expertise are being sidelined in the competitive scramble for access to ancient bones.
Ancient DNA research has enjoyed a tremendous amount of success in a very short period of time, and the latest results are often published in the most prestigious journals. This has led to great demand for access to old bones, especially from exotic places. These unique samples are often destroyed or damaged in the process of DNA extraction. Archaeologists may get credit for providing the bone samples that make high-profile papers possible, but some say they feel as though their own expertise is being ignored in the process. Some of them have been cited as co-authors on papers that directly contradict their own work. These misgivings are accompanied by a concern among the critics that some leading geneticists are being insensitive to the needs or priorities of indigenous communities. (These geneticists, for their part, believe these criticisms are unfounded; in their view, their high-quality work provides important data for scientists in a variety of fields to build on.) As the Times Magazine’s report notes, the controversy underscores not just a gap in priorities between different academic disciplines but also a conflict between two warring scholarly attitudes: on the one hand, “those bewitched by grand intellectual narratives,” and on the other hand, “those who wearily warn that such adventures rarely end well.”
Responses to the article from around the world
"You don't have to be an expert archaeologist to know that using 4 skulls to justify an entire new migration theory doesn't work. It may be correct but the conclusions are pre-mature just from a statistical perspective. Reich's aggressiveness to push it and dismiss everyone else sounds like someone in it for the publicity".
"This article sums up every problem that archaeology has as a discipline. The researchers drew sweeping conclusions from a convenience sample of three skulls. No technology makes it acceptable to trample on the basic principles of sampling. They might be right, they might be wrong, but they should be considerably more humble about their data. Moreover, the idea that a paper is "unrejectable," and Reich's apparent ability to persuade the editors of Nature that his paper is so, makes a mockery of peer review, the backbone of any science. It's ironic that no journal in any of the "softer" social sciences would have published a piece that made such claims based on obviously exploratory evidence."
