Lara Cassidy, a geneticist at Trinity College Dublin who was not involved in the research, described the study as “a triumph. It takes a step back and considers Bronze Age Britain on the macro scale, charting major movements of people over centuries that likely had profound cultural and linguistic consequences.”
Dr. Reich said the study demonstrated how, in the last few years, archaeologists and ancient DNA researchers have made great strides in coming together to address questions of interest to archaeologists.
“To a huge extent, this is due to the large ancient DNA sample sizes that it is now possible to generate economically,” he said. “These studies are also beginning to address questions that truly matter biologically and culturally.”
A pioneer in the swiftly evolving field of paleogenomics, Dr. Reich is a kind of puzzle master of human origins. By sequencing DNA from ancient skeletal remains and comparing it to the genetic material of individuals alive today, he and his collaborators piece together ancient population patterns that traditional archaeological and paleontological methods fail to identify. By overturning established theories and conventional wisdoms about migrations following the Ice Age, they are illuminating the mongrel nature of humanity.
For all the success of what Dr. Reich calls the “genomic ancient DNA revolution” in transforming our understanding of modern humans, the practice of extracting DNA from ancient human remains has raised ethical issues ranging from access to samples to ownership of cultural heritage. Critics point out that in some parts of the world, the very question of who should be considered Indigenous has the potential to fuel nationalism and xenophobia.
To respond to these concerns, three months ago Dr. Reich and 63 archaeologists, anthropologists, curators and geneticists from 31 countries drafted a set of global standards to handle genetic material, promote data sharing and properly engage Indigenous communities, although the guidelines did little to assuage critics.
Since languages “typically spread through movements of people,” Dr. Reich said, the wave of migration was a plausible vector for the diffusion of early Celtic dialects into Britain. “Everybody agrees that Celtic branched off from the old Indo-European mother tongue as it spread westward,” said Patrick Sims-Williams, emeritus professor of Celtic studies at Aberystwyth University. “But they have been arguing for years about when and where that branching took place.”