'Is Ancient DNA Research Revealing New Truths — or Falling Into Old Traps?' diff viewer (0/1)

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Is Ancient DNA Research Revealing New Truths — or Falling Into Old Traps?	Is Ancient DNA Research Revealing New Truths — or Falling Into Old Traps?
2019-01-17 15:40:05 UTC	2019-01-27 12:55:05 UTC (10 days later)
PART I	PART I
A faint aura of destiny seems to hover over Teouma Bay. It’s not so much the landscape, with its ravishing if boilerplate tropical splendor — banana and mango trees, coconut and pandanus palms, bougainvillea, the apprehensive trill of the gray-eared honeyeater — as it is the shape of the harbor itself, which betrays, in the midst of such organic profusion, an aspect of the unnatural. The bay, on the island of Efate in the South Pacific nation Vanuatu, is long, symmetrical and briskly rectangular. In the expected place of wavelets is a blue so calm and unbroken that the sea doesn’t so much crash on the land as neatly abut it. From above, it looks as though a safe harbor had been engraved in the shoreline by some celestial engineer.	A faint aura of destiny seems to hover over Teouma Bay. It’s not so much the landscape, with its ravishing if boilerplate tropical splendor — banana and mango trees, coconut and pandanus palms, bougainvillea, the apprehensive trill of the gray-eared honeyeater — as it is the shape of the harbor itself, which betrays, in the midst of such organic profusion, an aspect of the unnatural. The bay, on the island of Efate in the South Pacific nation Vanuatu, is long, symmetrical and briskly rectangular. In the expected place of wavelets is a blue so calm and unbroken that the sea doesn’t so much crash on the land as neatly abut it. From above, it looks as though a safe harbor had been engraved in the shoreline by some celestial engineer.
In late 2003, while clearing land just above the seaside, a bulldozer driver found a broken piece of pottery in the rubble. The villagers of Vanuatu often happen upon shards of timeworn ceramic, which spark an idly mythical curiosity; they’re said to be fragments of Noah’s Ark, or the original Ten Commandments, or the burst water vessels of powerful ancestral spirits. These shards are often left alone, but word in this particular case traveled quickly, and the artifact soon found its way to the Vanuatu Cultural Center and National Museum, where Stuart Bedford, a New Zealand archaeologist who had studied local pot shards for years, was called in to inspect it. He immediately recognized its distinctive pattern — “dentate stamping,” an ancient technique so named because it looked as though some tiny-toothed creature had bitten an intricate pattern into the ceramic — and understood that this pottery coincided with the very first movement of ancient peoples into the South Seas.	In late 2003, while clearing land just above the seaside, a bulldozer driver found a broken piece of pottery in the rubble. The villagers of Vanuatu often happen upon shards of timeworn ceramic, which spark an idly mythical curiosity; they’re said to be fragments of Noah’s Ark, or the original Ten Commandments, or the burst water vessels of powerful ancestral spirits. These shards are often left alone, but word in this particular case traveled quickly, and the artifact soon found its way to the Vanuatu Cultural Center and National Museum, where Stuart Bedford, a New Zealand archaeologist who had studied local pot shards for years, was called in to inspect it. He immediately recognized its distinctive pattern — “dentate stamping,” an ancient technique so named because it looked as though some tiny-toothed creature had bitten an intricate pattern into the ceramic — and understood that this pottery coincided with the very first movement of ancient peoples into the South Seas.
Bedford rushed to the site of the discovery, an old colonial coconut plantation that the bulldozer had been clearing for use as a prawn farm. Further burrowing turned up not only more pottery but also tools of obsidian and a great cache of human bones, which had lain undisturbed and unusually well preserved over thousands of years. The site was soon identified as the oldest and largest prehistoric cemetery ever found in the Pacific. Everything at the site indicated a founding colony — first arrivals to the shores of uninhabited islands. Teouma was, according to Bedford, “unlike anything anyone had ever seen, or was likely to see, in this part of the world ever again.”	Bedford rushed to the site of the discovery, an old colonial coconut plantation that the bulldozer had been clearing for use as a prawn farm. Further burrowing turned up not only more pottery but also tools of obsidian and a great cache of human bones, which had lain undisturbed and unusually well preserved over thousands of years. The site was soon identified as the oldest and largest prehistoric cemetery ever found in the Pacific. Everything at the site indicated a founding colony — first arrivals to the shores of uninhabited islands. Teouma was, according to Bedford, “unlike anything anyone had ever seen, or was likely to see, in this part of the world ever again.”
Archaeologists hoped the bones might help provide a clue to the abiding mystery of how anybody had gotten to these far-off coastlines in the first place. Vanuatu is a volcanic archipelago of more than 80 islands littered in an extended slingshot shape across an 800-mile arc of the South Pacific. Europeans first heard of its existence in 1606, when a Portuguese navigator stopped through on a brief but violent imperial errand for the Spanish crown. The islands were largely left to their own devices until the end of the 18th century, when French and British ships arrived to plant their own flags. The two countries ruled the archipelago as a joint colony, called the Condominium of the New Hebrides, until independence was achieved in 1980. National coherence remains a work in progress. By some measures, Vanuatu is per capita the most linguistically diverse country on the planet: Its quarter-million citizens, predominantly the native ni-Vanuatu, speak as many as 140 different indigenous languages and maintain an astonishing variety of cultural practices. A meaningful national identity has been constructed from a common appreciation of ceremonial pig-tusk bracelets and the taking of kava, a very mild narcotic root that looks like primordial pea soup and tastes like a fine astringent dirt. Above all, however, the ni-Vanuatu are bound together by the fact of the country’s nautical isolation: Their nearest neighbors are hundreds of miles in any direction.	Archaeologists hoped the bones might help provide a clue to the abiding mystery of how anybody had gotten to these far-off coastlines in the first place. Vanuatu is a volcanic archipelago of more than 80 islands littered in an extended slingshot shape across an 800-mile arc of the South Pacific. Europeans first heard of its existence in 1606, when a Portuguese navigator stopped through on a brief but violent imperial errand for the Spanish crown. The islands were largely left to their own devices until the end of the 18th century, when French and British ships arrived to plant their own flags. The two countries ruled the archipelago as a joint colony, called the Condominium of the New Hebrides, until independence was achieved in 1980. National coherence remains a work in progress. By some measures, Vanuatu is per capita the most linguistically diverse country on the planet: Its quarter-million citizens, predominantly the native ni-Vanuatu, speak as many as 140 different indigenous languages and maintain an astonishing variety of cultural practices. A meaningful national identity has been constructed from a common appreciation of ceremonial pig-tusk bracelets and the taking of kava, a very mild narcotic root that looks like primordial pea soup and tastes like a fine astringent dirt. Above all, however, the ni-Vanuatu are bound together by the fact of the country’s nautical isolation: Their nearest neighbors are hundreds of miles in any direction.
It is the peculiar geography of this isolation that made the Teouma site so significant. Many of the islands of the South Pacific are much farther-flung: Easter Island makes Vanuatu look like an Australian exurb. But with one very small exception — the tiny eastern outliers of the Solomon Islands — Vanuatu offers the first solid ground on the far side of a major but invisible maritime boundary. On the west side of that border is a string of archipelagoes called Near Oceania: islands chained to one another (and to the rest of the world) by lines of sight. Prehistoric peoples, after tens of thousands of years of travel by foot from Africa, had arrived at the end of Southeast Asia and hopscotched their way forward via short sea outings, presumably crossing the narrow channels they encountered on crude watercraft. Finally, however, some 40,000 years ago, their path was decisively blocked by open ocean. In front of them, across more than 200 miles of empty sea, was the vast aquatic wilderness of Remote Oceania.	It is the peculiar geography of this isolation that made the Teouma site so significant. Many of the islands of the South Pacific are much farther-flung: Easter Island makes Vanuatu look like an Australian exurb. But with one very small exception — the tiny eastern outliers of the Solomon Islands — Vanuatu offers the first solid ground on the far side of a major but invisible maritime boundary. On the west side of that border is a string of archipelagoes called Near Oceania: islands chained to one another (and to the rest of the world) by lines of sight. Prehistoric peoples, after tens of thousands of years of travel by foot from Africa, had arrived at the end of Southeast Asia and hopscotched their way forward via short sea outings, presumably crossing the narrow channels they encountered on crude watercraft. Finally, however, some 40,000 years ago, their path was decisively blocked by open ocean. In front of them, across more than 200 miles of empty sea, was the vast aquatic wilderness of Remote Oceania.
[5 takeaways from this report on ancient DNA research.]	[5 takeaways from this report on ancient DNA research.]
That border marked the absolute limit of human expansion for tens of thousands of years, until at last someone sailed out across the naval event horizon and into the unknown. This first traversal was one of the greatest and most courageous passages in human prehistory. The peopling of Remote Oceania — an obscure exodus that easily ranks among the signal triumphs of the ancient world — has inspired awe and vexation for generations. In the mid-20th century, archaeologists came to identify these first voyagers with a set of jars and tools unique to the region, the “Lapita cultural complex,” and determined that they crossed the boundary into Remote Oceania some 3,000 years ago. Further details were presumed lost to history.	That border marked the absolute limit of human expansion for tens of thousands of years, until at last someone sailed out across the naval event horizon and into the unknown. This first traversal was one of the greatest and most courageous passages in human prehistory. The peopling of Remote Oceania — an obscure exodus that easily ranks among the signal triumphs of the ancient world — has inspired awe and vexation for generations. In the mid-20th century, archaeologists came to identify these first voyagers with a set of jars and tools unique to the region, the “Lapita cultural complex,” and determined that they crossed the boundary into Remote Oceania some 3,000 years ago. Further details were presumed lost to history.
But in 2014, Bedford got another surprise call, this time from a researcher affiliated with a genetics team at Harvard. A small group of pioneering lab scientists had found ways to isolate and analyze DNA from ancient bones, methods potent enough to inspire a wholesale revision of our knowledge about ancient peoples. The Harvard operation, which was then preparing a landmark paper about European origins, now intended to visit their attention upon the South Pacific, and they wanted to know whether Bedford might facilitate access to the Teouma remains. Bedford agreed, and over the next four years, the Harvard team used the DNA they found to present a radical new story about Remote Oceania’s first settlers.	But in 2014, Bedford got another surprise call, this time from a researcher affiliated with a genetics team at Harvard. A small group of pioneering lab scientists had found ways to isolate and analyze DNA from ancient bones, methods potent enough to inspire a wholesale revision of our knowledge about ancient peoples. The Harvard operation, which was then preparing a landmark paper about European origins, now intended to visit their attention upon the South Pacific, and they wanted to know whether Bedford might facilitate access to the Teouma remains. Bedford agreed, and over the next four years, the Harvard team used the DNA they found to present a radical new story about Remote Oceania’s first settlers.
Bedford and I met last summer in the hilly and sedate capital of Port-Vila, outside the towering thatched A-frame of the national museum. He is tall and friendly, with a square head, short brown hair, a rancher’s open gait and the incessant squint of someone in perpetual communion with the near-hopeless complication of human affairs. We climbed into his white Land Cruiser and drove to a tidy village compound outside town. There, Bedford embraced the local chief, Silas Alben, who led us through village gardens of banana and tuber to a high limestone cliff with a sprawling view of the Teouma site.	Bedford and I met last summer in the hilly and sedate capital of Port-Vila, outside the towering thatched A-frame of the national museum. He is tall and friendly, with a square head, short brown hair, a rancher’s open gait and the incessant squint of someone in perpetual communion with the near-hopeless complication of human affairs. We climbed into his white Land Cruiser and drove to a tidy village compound outside town. There, Bedford embraced the local chief, Silas Alben, who led us through village gardens of banana and tuber to a high limestone cliff with a sprawling view of the Teouma site.
As we shared the sweating neon flesh of a machete-split papaya, Bedford, now affiliated with the Australian National University, ran through all the reasons that the sheltered cove far below — just then rippling beneath a late-afternoon rainbow — would have made an inviting stage for the encounter of an ancient people with a primeval place. For whoever arrived in those first canoes, these empty islands offered a bounty of unfished reefs, unoccupied land and naïve, slow-moving animal prey; for those who now studied those first colonists, their arrival represented an important inflection point in human expansion and development. And now, the science of “paleogenomics” had coaxed new stories of ancient lives from the Teouma bones.	As we shared the sweating neon flesh of a machete-split papaya, Bedford, now affiliated with the Australian National University, ran through all the reasons that the sheltered cove far below — just then rippling beneath a late-afternoon rainbow — would have made an inviting stage for the encounter of an ancient people with a primeval place. For whoever arrived in those first canoes, these empty islands offered a bounty of unfished reefs, unoccupied land and naïve, slow-moving animal prey; for those who now studied those first colonists, their arrival represented an important inflection point in human expansion and development. And now, the science of “paleogenomics” had coaxed new stories of ancient lives from the Teouma bones.
For most of human history, our beliefs about our origins drew upon oral traditions or the evidence found in ancient texts. One 17th-century scholar calculated, on the basis of biblical genealogies, that the creation happened in 4004 B.C.; subsequent refinements settled on the date of Oct. 23. Sir Isaac Newton criticized the ancient Egyptians for the “vanity” of their own calendrical reckoning, which placed the beginning of their monarchy before the existence of the world. As the pre-eminent British archaeologist Colin Renfrew once put it, “For an educated man in the 17th or even the 18th century, any suggestion that the human past extended back further than 6,000 years was a vain and foolish speculation.”	For most of human history, our beliefs about our origins drew upon oral traditions or the evidence found in ancient texts. One 17th-century scholar calculated, on the basis of biblical genealogies, that the creation happened in 4004 B.C.; subsequent refinements settled on the date of Oct. 23. Sir Isaac Newton criticized the ancient Egyptians for the “vanity” of their own calendrical reckoning, which placed the beginning of their monarchy before the existence of the world. As the pre-eminent British archaeologist Colin Renfrew once put it, “For an educated man in the 17th or even the 18th century, any suggestion that the human past extended back further than 6,000 years was a vain and foolish speculation.”
It wasn’t long before a series of scientific interventions pried open human prehistory to methodical study. Two great advances of 1859 helped cement the view that 4004 B.C. was not, in fact, the starting point of all human activity. The first was the argument, made by a geologist and an antiquarian, that animal remains found alongside stone tools in Britain and France proved the antiquity of the human race. The second was the publication of Darwin’s “On the Origin of Species,” which was incompatible with both the specifics of biblical creationism and the more general proposition that the world was only a few thousand years old. It was all of a sudden widely plausible that stuff in the ground had been there for an unimaginably long time.	It wasn’t long before a series of scientific interventions pried open human prehistory to methodical study. Two great advances of 1859 helped cement the view that 4004 B.C. was not, in fact, the starting point of all human activity. The first was the argument, made by a geologist and an antiquarian, that animal remains found alongside stone tools in Britain and France proved the antiquity of the human race. The second was the publication of Darwin’s “On the Origin of Species,” which was incompatible with both the specifics of biblical creationism and the more general proposition that the world was only a few thousand years old. It was all of a sudden widely plausible that stuff in the ground had been there for an unimaginably long time.
Before anyone could even begin to tell an ordered story about what might have happened, however, there needed to be a way to differentiate what happened sooner from what happened later. In the early 20th century, geologists and archaeologists began to draw upon contemporary observations of regular sedimentary deposits to project elementary prehistorical “clocks” backward in time. The end of the last ice age, for example, was set at about 10,000 years ago. Archaeologists then realized that they could cross-reference these geological clocks with the earliest written documents, ancient Egyptian and Mesopotamian records that reached back 4,000 or 5,000 years. If geological time could be roughly calibrated everywhere, and if even a smattering of places had left behind calendars, recorded history could be tied to sedimentary chronology and true dates derived from the ground.	Before anyone could even begin to tell an ordered story about what might have happened, however, there needed to be a way to differentiate what happened sooner from what happened later. In the early 20th century, geologists and archaeologists began to draw upon contemporary observations of regular sedimentary deposits to project elementary prehistorical “clocks” backward in time. The end of the last ice age, for example, was set at about 10,000 years ago. Archaeologists then realized that they could cross-reference these geological clocks with the earliest written documents, ancient Egyptian and Mesopotamian records that reached back 4,000 or 5,000 years. If geological time could be roughly calibrated everywhere, and if even a smattering of places had left behind calendars, recorded history could be tied to sedimentary chronology and true dates derived from the ground.
This was heralded as a magnificent advance. The trouble, as it turned out, was that an emphasis on written records from Egypt and the Middle East prompted scholars to take for granted the cultural superiority of those early civilizations and to make major assumptions on that basis — Stonehenge, for example, simply had to have followed the majesty of the Great Pyramids.	This was heralded as a magnificent advance. The trouble, as it turned out, was that an emphasis on written records from Egypt and the Middle East prompted scholars to take for granted the cultural superiority of those early civilizations and to make major assumptions on that basis — Stonehenge, for example, simply had to have followed the majesty of the Great Pyramids.
In 1949, the invention of radiocarbon dating, by the American physical chemist Willard F. Libby, turned the whole field upside down. By giving cosmically certain dates rather than cross-referenced estimations, radiocarbon dating undermined virtually all of archaeology’s basic premises. (Stonehenge could not have been patterned after the Great Pyramids if it was built at the same time as Giza.) There was stubborn resistance to the new lab results. These dates, pronounced one vaunted Edinburgh archaeologist with a now-notorious sniff, are “archaeologically unacceptable.” By the early 1960s, they could no longer be ignored, and a new generation of archaeologists gutted the discipline and rebuilt it with very different assumptions — ones that did not rely on the idea that a few peoples of first-rate culture and pedigree had been responsible for humanity’s major steps forward.	In 1949, the invention of radiocarbon dating, by the American physical chemist Willard F. Libby, turned the whole field upside down. By giving cosmically certain dates rather than cross-referenced estimations, radiocarbon dating undermined virtually all of archaeology’s basic premises. (Stonehenge could not have been patterned after the Great Pyramids if it was built at the same time as Giza.) There was stubborn resistance to the new lab results. These dates, pronounced one vaunted Edinburgh archaeologist with a now-notorious sniff, are “archaeologically unacceptable.” By the early 1960s, they could no longer be ignored, and a new generation of archaeologists gutted the discipline and rebuilt it with very different assumptions — ones that did not rely on the idea that a few peoples of first-rate culture and pedigree had been responsible for humanity’s major steps forward.
If prehistorians had learned one hard lesson from chemists, their colleagues in biology departments were slowly laying the groundwork for another. In 1967, the molecular biologist Allan Wilson at the University of California, Berkeley, along with one of his students, Vincent Sarich, demonstrated that evolutionary relationships between species could be determined not only from fossils but also, via a quantitative analysis of blood proteins, from living specimens. Humans and apes, Wilson found, diverged only five million years ago — far more recently than previously believed.	If prehistorians had learned one hard lesson from chemists, their colleagues in biology departments were slowly laying the groundwork for another. In 1967, the molecular biologist Allan Wilson at the University of California, Berkeley, along with one of his students, Vincent Sarich, demonstrated that evolutionary relationships between species could be determined not only from fossils but also, via a quantitative analysis of blood proteins, from living specimens. Humans and apes, Wilson found, diverged only five million years ago — far more recently than previously believed.
Within the decade, researchers trained in the discipline of population genetics would get in on the historical act. Every contemporary genome is a mosaic of individual tiles passed along from thousands of ancestors; each of us thus contains not only our “own” ancestry but those of multitudes. With each new generation, random mutations, like misspellings, are introduced into a population; some of these will disappear over time, but others will increase in frequency until they are common enough to become a statistically significant part of a population’s genetic signature. If two populations have been distinct for a long time — that is, if people from one don’t tend to mate with people from the other — they will share fewer of these mutations; if they encountered each other and were fruitful, their mutation frequencies will overlap. These insights could be made relevant to prehistorians insofar as they could demonstrate that modern human populations were forged in the mixture of ancient ones. It was still mostly impossible, though, to conclude anything about when these groups might have mixed, or where, or how.	Within the decade, researchers trained in the discipline of population genetics would get in on the historical act. Every contemporary genome is a mosaic of individual tiles passed along from thousands of ancestors; each of us thus contains not only our “own” ancestry but those of multitudes. With each new generation, random mutations, like misspellings, are introduced into a population; some of these will disappear over time, but others will increase in frequency until they are common enough to become a statistically significant part of a population’s genetic signature. If two populations have been distinct for a long time — that is, if people from one don’t tend to mate with people from the other — they will share fewer of these mutations; if they encountered each other and were fruitful, their mutation frequencies will overlap. These insights could be made relevant to prehistorians insofar as they could demonstrate that modern human populations were forged in the mixture of ancient ones. It was still mostly impossible, though, to conclude anything about when these groups might have mixed, or where, or how.
The answers to those questions required not just contemporary genetic data but actual prehistoric DNA. The idea that it might be preserved in old specimens has been around since 1984, when Wilson announced that his lab had extracted DNA from the salted skin of a quagga, an extinct equine species with the head of a zebra and the haunches of a donkey. The further possibilities suggested by ancient DNA were awarded a special place in the public imagination by the 1993 release of Steven Spielberg’s “Jurassic Park.” But even as the journal Nature capitalized on the premiere with a paper that sequenced the DNA of an amber-trapped weevil — a study rendered dubious after widespread speculation that the sample had been contaminated with the researchers’ own DNA — observers wondered whether the sequencing of ancient genomes was just a neat trick or research of actual value.	The answers to those questions required not just contemporary genetic data but actual prehistoric DNA. The idea that it might be preserved in old specimens has been around since 1984, when Wilson announced that his lab had extracted DNA from the salted skin of a quagga, an extinct equine species with the head of a zebra and the haunches of a donkey. The further possibilities suggested by ancient DNA were awarded a special place in the public imagination by the 1993 release of Steven Spielberg’s “Jurassic Park.” But even as the journal Nature capitalized on the premiere with a paper that sequenced the DNA of an amber-trapped weevil — a study rendered dubious after widespread speculation that the sample had been contaminated with the researchers’ own DNA — observers wondered whether the sequencing of ancient genomes was just a neat trick or research of actual value.
Over the past few years, a growing cohort of scientists has at last produced a fantastic answer. Ancient DNA, they believe, not only allows us to cut through what scholars once wrote off as “wrapped in a thick fog” of “heathendom.” It promises nothing less than what the Harvard geneticist David Reich has called “the genome revolution in the study of the human past.”	Over the past few years, a growing cohort of scientists has at last produced a fantastic answer. Ancient DNA, they believe, not only allows us to cut through what scholars once wrote off as “wrapped in a thick fog” of “heathendom.” It promises nothing less than what the Harvard geneticist David Reich has called “the genome revolution in the study of the human past.”
David Reich’s lab is folded into a corner of a glassy, long-corridored labyrinth at Harvard Medical School. The only exterior advertisements of the nature of his research are large mounted maps of landforms all around the world. One afternoon last fall, as I stood and examined a continent, Reich materialized beside me. He is a long-limbed man with a lithe, almost balletic figure, and he wore a closefitting pullover and fading coral chinos. Though his hairline has receded and the curls behind his ears are graying, a boyish precocity makes him seem much younger than his 44 years. He led me swiftly past a confab of postdocs and into his windowed office. There was very little in the way of adornment, save a ghostly, truncated branch of the Indo-European language tree (“Greek,” “Armenian”) that someone had sketched out, on the wall over his desk, with what looked a permanent marker.	David Reich’s lab is folded into a corner of a glassy, long-corridored labyrinth at Harvard Medical School. The only exterior advertisements of the nature of his research are large mounted maps of landforms all around the world. One afternoon last fall, as I stood and examined a continent, Reich materialized beside me. He is a long-limbed man with a lithe, almost balletic figure, and he wore a closefitting pullover and fading coral chinos. Though his hairline has receded and the curls behind his ears are graying, a boyish precocity makes him seem much younger than his 44 years. He led me swiftly past a confab of postdocs and into his windowed office. There was very little in the way of adornment, save a ghostly, truncated branch of the Indo-European language tree (“Greek,” “Armenian”) that someone had sketched out, on the wall over his desk, with what looked a permanent marker.
In his recent book, Reich ranks the “ancient-DNA revolution” with the invention of the microscope. Ancient DNA, his research suggests, can explain with more certainty and detail than any previous technique the course of human evolution, history and identity — as he puts it in the book’s title, “Who We Are and How We Got Here.” Though Reich works with samples that are thousands or tens of thousands of years old, the phrase “ancient DNA” encompasses any old genetic material that has been heavily degraded, and Reich’s work has been made possible only by a series of technological and procedural advances. Researchers in the field ship or hand-carry the bones to Harvard, where clean-suited technicians expose them to ultraviolet light to prevent contamination, then bore holes in them with dental drills. These skeletal remains are often rare — one pinkie-finger fragment that researchers in a lab in Leipzig used to demonstrate the existence of a long-extinct form of archaic humans was one of only four such bones ever found. Minuscule portions of genetic code are isolated and enriched, then read by expensive sequencers; statistical techniques then plot the relationship between this particular sample and thousands more in enormous data sets.	In his recent book, Reich ranks the “ancient-DNA revolution” with the invention of the microscope. Ancient DNA, his research suggests, can explain with more certainty and detail than any previous technique the course of human evolution, history and identity — as he puts it in the book’s title, “Who We Are and How We Got Here.” Though Reich works with samples that are thousands or tens of thousands of years old, the phrase “ancient DNA” encompasses any old genetic material that has been heavily degraded, and Reich’s work has been made possible only by a series of technological and procedural advances. Researchers in the field ship or hand-carry the bones to Harvard, where clean-suited technicians expose them to ultraviolet light to prevent contamination, then bore holes in them with dental drills. These skeletal remains are often rare — one pinkie-finger fragment that researchers in a lab in Leipzig used to demonstrate the existence of a long-extinct form of archaic humans was one of only four such bones ever found. Minuscule portions of genetic code are isolated and enriched, then read by expensive sequencers; statistical techniques then plot the relationship between this particular sample and thousands more in enormous data sets.
Reich inherited from his parents a humanistic bent: His mother, Tova, is a novelist of some renown; his father, Walter, is a psychiatrist who was the first director of the United States Holocaust Memorial Museum in Washington. He entered Harvard with an inclination toward social studies, but halfway through, in pursuit of greater rigor, he switched to physics; after graduation, he went to Oxford, where he studied biochemistry with the idea that he might go on to medical school. The impression he gives when talking about these years is one of restless intellectual ambition in search of a commensurate object. He eventually returned to Oxford to complete a doctorate, in zoology, where he at last found a sense of belonging in the lineage of Luca Cavalli-Sforza, a population geneticist who spearheaded efforts to make historical inquiry resemble a hard science.	Reich inherited from his parents a humanistic bent: His mother, Tova, is a novelist of some renown; his father, Walter, is a psychiatrist who was the first director of the United States Holocaust Memorial Museum in Washington. He entered Harvard with an inclination toward social studies, but halfway through, in pursuit of greater rigor, he switched to physics; after graduation, he went to Oxford, where he studied biochemistry with the idea that he might go on to medical school. The impression he gives when talking about these years is one of restless intellectual ambition in search of a commensurate object. He eventually returned to Oxford to complete a doctorate, in zoology, where he at last found a sense of belonging in the lineage of Luca Cavalli-Sforza, a population geneticist who spearheaded efforts to make historical inquiry resemble a hard science.
After abandoning medical school at Harvard for a postdoc at M.I.T., Reich returned to Harvard to establish his own medical-genetics lab. His chief interest lay in the effort to design novel statistical approaches to better explain how populations were related to one another. He showed, for example, on the basis of contemporary genetic data, that modern Indians are in fact a product of two highly distinct groups, one that had been on the subcontinent for thousands of years and another that formed more recently.	After abandoning medical school at Harvard for a postdoc at M.I.T., Reich returned to Harvard to establish his own medical-genetics lab. His chief interest lay in the effort to design novel statistical approaches to better explain how populations were related to one another. He showed, for example, on the basis of contemporary genetic data, that modern Indians are in fact a product of two highly distinct groups, one that had been on the subcontinent for thousands of years and another that formed more recently.
He got his first opportunity to study ancient DNA when Svante Paabo — a Swedish geneticist who had worked with Wilson — enlisted Reich in his efforts, based out of a lab in Leipzig, to sequence the entirety of the Neanderthal genome. Reich’s analysis helped demonstrate that most living humans, with the general exception of sub-Saharan Africans, have some Neanderthal ancestry. “It was clear with the sequencing of the Neanderthal,” Reich told me in his office, “that this was obviously the best data in the world in any type of science.” It didn’t just tell you that Indians were a mixed group; it could, in theory, specify the moment where and when that mixture began.	He got his first opportunity to study ancient DNA when Svante Paabo — a Swedish geneticist who had worked with Wilson — enlisted Reich in his efforts, based out of a lab in Leipzig, to sequence the entirety of the Neanderthal genome. Reich’s analysis helped demonstrate that most living humans, with the general exception of sub-Saharan Africans, have some Neanderthal ancestry. “It was clear with the sequencing of the Neanderthal,” Reich told me in his office, “that this was obviously the best data in the world in any type of science.” It didn’t just tell you that Indians were a mixed group; it could, in theory, specify the moment where and when that mixture began.
So in 2013, Reich, along with a veteran of Paabo’s lab and a longtime mathematician collaborator, retooled his shop at Harvard Medical School as one of the country’s first dedicated ancient-DNA labs. The idea, he writes in his book, “was to make ancient DNA industrial — to build an American-style genomics factory” that would liberate such fields as archaeology, history and anthropology from hitherto insoluble debates.	So in 2013, Reich, along with a veteran of Paabo’s lab and a longtime mathematician collaborator, retooled his shop at Harvard Medical School as one of the country’s first dedicated ancient-DNA labs. The idea, he writes in his book, “was to make ancient DNA industrial — to build an American-style genomics factory” that would liberate such fields as archaeology, history and anthropology from hitherto insoluble debates.
He was more successful than even he anticipated. By the end of 2010, only five ancient genomes had been sequenced in total, but in 2014, 38 were done in one year. Soon the number will be close to 2,000. Reich’s lab alone is responsible for at least half of the published output, which doesn’t include some 5,500 more bones in the process of being analyzed and 3,000 more in storage. “Ancient DNA and the genome revolution,” he declares in his book’s introductory overture, “can now answer a previously unresolvable question about the deep past: the question of what happened.”	He was more successful than even he anticipated. By the end of 2010, only five ancient genomes had been sequenced in total, but in 2014, 38 were done in one year. Soon the number will be close to 2,000. Reich’s lab alone is responsible for at least half of the published output, which doesn’t include some 5,500 more bones in the process of being analyzed and 3,000 more in storage. “Ancient DNA and the genome revolution,” he declares in his book’s introductory overture, “can now answer a previously unresolvable question about the deep past: the question of what happened.”
Everybody pretty much agrees that the story of what happened began in Africa, with the evolution of modern humans; later, as of 50,000 to 100,000 years ago, the human story continued on the other continents. As Reich sees it, the study of ancient DNA has disproved our conjectures about what happened next. 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. Nonindigenous people seek the same rootedness in consumer ancestry services like 23andMe, which declare that they’re “Spanish” or “Yoruba.”	Everybody pretty much agrees that the story of what happened began in Africa, with the evolution of modern humans; later, as of 50,000 to 100,000 years ago, the human story continued on the other continents. As Reich sees it, the study of ancient DNA has disproved our conjectures about what happened next. 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. Nonindigenous people seek the same rootedness in consumer ancestry services like 23andMe, which declare that they’re “Spanish” or “Yoruba.”
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. Paabo had shown that early humans mated with Neanderthals, but that was only one small part of the swirling “admixture” that characterized human interbreeding. Even after the Neanderthals became extinct, roughly 40,000 years ago, the archaic human populations of the earth — Reich gives them names like Ancient North Eurasians — were utterly unlike the populations we see today.	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. Paabo had shown that early humans mated with Neanderthals, but that was only one small part of the swirling “admixture” that characterized human interbreeding. Even after the Neanderthals became extinct, roughly 40,000 years ago, the archaic human populations of the earth — Reich gives them names like Ancient North Eurasians — were utterly unlike the populations we see today.
While Paabo continued to work on the Neanderthal period, Reich devoted his energy to obtaining samples from the last 10,000 or so years — the historical domain of archaeologists. Ancient DNA’s “big bang,” as more than one geneticist described it to me, came with the 2015 publication, in Nature, of a Reich paper called “Massive Migration From the Steppe Was a Source for Indo-European Languages in Europe.” On the basis of genetic information culled from 69 ancient individuals dug up by collaborating archaeologists in Scandinavia, Western Europe and Russia, the paper argued that Europeans aren’t quite who they thought they were. About 5,000 years ago, a “relatively sudden” mass migration of nomadic herders from the east — the steppes of eastern Ukraine and southern Russia — swept in and almost entirely replaced ~~the~~ ~~continent’s~~ existing communities of hunter-gatherers and early ~~farmers.~~ These newcomers were known to exploit many of the cutting-edge technologies of the time: the domestication of horses, the wheel and, perhaps most salient, axes and spearheads of copper. (Their corpses sometimes featured cutting-edge wounds.)	While Paabo continued to work on the Neanderthal period, Reich devoted his energy to obtaining samples from the last 10,000 or so years — the historical domain of archaeologists. Ancient DNA’s “big bang,” as more than one geneticist described it to me, came with the 2015 publication, in Nature, of a Reich paper called “Massive Migration From the Steppe Was a Source for Indo-European Languages in Europe.” On the basis of genetic information culled from 69 ancient individuals dug up by collaborating archaeologists in Scandinavia, Western Europe and Russia, the paper argued that Europeans aren’t quite who they thought they were. About 5,000 years ago, a “relatively sudden” mass migration of nomadic herders from the east — the steppes of eastern Ukraine and southern Russia — swept in and almost entirely replaced existing communities of hunter-gatherers and early farmers in Central and Northern Europe. These newcomers were known to exploit many of the cutting-edge technologies of the time: the domestication of horses, the wheel and, perhaps most salient, axes and spearheads of copper. (Their corpses sometimes featured cutting-edge wounds.)
The Reich team inferred that the major source of contemporary European ancestry — and probably Indo-European languages as well — was not, in fact, from Europe but from far to the east. And this discovery, confirmed by the near-simultaneous publication of almost identical results from a competing ancient-DNA lab in Denmark, had monumental implications for science’s understanding of the whole ancient world. Great migration events — like the movement of Siberian peoples into North America or the spread of voyagers into the Pacific — were not outliers but the norm. After Europe and India, there were similar mass migrations identified in Africa, the Middle East and Southeast Asia. No one ever expected that we could possibly amass so much new evidence about the human past. And no one was producing this work at the pace and throughput of David Reich and his genomics factory. Most scientists felt lucky if they published one or at the most two Nature papers in a lifetime. Reich was publishing three or four a year.	The Reich team inferred that the major source of contemporary European ancestry — and probably Indo-European languages as well — was not, in fact, from Europe but from far to the east. And this discovery, confirmed by the near-simultaneous publication of almost identical results from a competing ancient-DNA lab in Denmark, had monumental implications for science’s understanding of the whole ancient world. Great migration events — like the movement of Siberian peoples into North America or the spread of voyagers into the Pacific — were not outliers but the norm. After Europe and India, there were similar mass migrations identified in Africa, the Middle East and Southeast Asia. No one ever expected that we could possibly amass so much new evidence about the human past. And no one was producing this work at the pace and throughput of David Reich and his genomics factory. Most scientists felt lucky if they published one or at the most two Nature papers in a lifetime. Reich was publishing three or four a year.
There was an obvious pattern to the great migratory arrows freshly drawn across world geography, which were often coincident with the spread of technology or agricultural practices. Earlier paleogenomic results established thousands of years of heady mixture among long-forgotten ancient populations. With the relatively recent rise of everything we associate with “culture” — technologies like agriculture, metallurgy and eventually writing — much of this continuous “admixture” began to give way, it seemed, to discontinuous episodes better characterized as “replacement” or “turnover.” That is, about 5,000 to 9,000 years ago, human history was, at least in a few crucial places, less about various groups coming together and more about some groups blotting out their neighbors.	There was an obvious pattern to the great migratory arrows freshly drawn across world geography, which were often coincident with the spread of technology or agricultural practices. Earlier paleogenomic results established thousands of years of heady mixture among long-forgotten ancient populations. With the relatively recent rise of everything we associate with “culture” — technologies like agriculture, metallurgy and eventually writing — much of this continuous “admixture” began to give way, it seemed, to discontinuous episodes better characterized as “replacement” or “turnover.” That is, about 5,000 to 9,000 years ago, human history was, at least in a few crucial places, less about various groups coming together and more about some groups blotting out their neighbors.
This was not only relevant as an eccentricity of prehistoric demography, but broadly consequential for the ongoing study of culture itself — of where new ideas come from and how they proliferate. When we thought of populations as stationary and largely stable, we assumed that whatever evolutionary progress they made, from toolmaking to agriculture, reflected either a native innovation or the incorporation of some adjacent group’s avant-garde practice. Now it seemed as though culture was less about the invention and spread of new ideas and more about the mass movements of particular peoples — and the resulting integration, outcompetition or extermination of the communities they overran. Previously, it was possible to think about prehistory as a kind of grand bazaar. Now the operative metaphor (as multiple science journalists observed) was more like Risk, or even “Game of Thrones.”	This was not only relevant as an eccentricity of prehistoric demography, but broadly consequential for the ongoing study of culture itself — of where new ideas come from and how they proliferate. When we thought of populations as stationary and largely stable, we assumed that whatever evolutionary progress they made, from toolmaking to agriculture, reflected either a native innovation or the incorporation of some adjacent group’s avant-garde practice. Now it seemed as though culture was less about the invention and spread of new ideas and more about the mass movements of particular peoples — and the resulting integration, outcompetition or extermination of the communities they overran. Previously, it was possible to think about prehistory as a kind of grand bazaar. Now the operative metaphor (as multiple science journalists observed) was more like Risk, or even “Game of Thrones.”
The ancient-DNA revolution seemed unlikely to have anything to say about Oceania, where the heat and humidity made the preservation of DNA implausible. But in 2014, Stuart Bedford got that second surprise call, from a Dublin-based archaeologist named Ron Pinhasi, a frequent Reich collaborator and procurer of samples. Pinhasi had discovered that the inner ear’s petrous bone, one of the densest in the body, often preserved vast quantities of genetic material. Could he and Reich examine the skulls of Teouma? In Vanuatu, human remains are often associated with ancestral spirits and are thus taboo — understandably, Bedford emphasized to me, explaining that he wouldn’t be comfortable digging up and boring into “Granddad.” But in this case, the ni-Vanuatu expressed no reservations: Local oral traditions contained no sacred reference to the Teouma dead, and Chief Alben gave his blessing. One of Bedford’s colleagues opened the skulls in a workshop warren behind the national museum, extracted the nubbins of petrous bone and shipped them to Dublin, where they were sandblasted. There turned out to be DNA in three of the samples. It was the first to be found in the tropics and suggested the opening of wide new fronts in ancient-DNA research.	The ancient-DNA revolution seemed unlikely to have anything to say about Oceania, where the heat and humidity made the preservation of DNA implausible. But in 2014, Stuart Bedford got that second surprise call, from a Dublin-based archaeologist named Ron Pinhasi, a frequent Reich collaborator and procurer of samples. Pinhasi had discovered that the inner ear’s petrous bone, one of the densest in the body, often preserved vast quantities of genetic material. Could he and Reich examine the skulls of Teouma? In Vanuatu, human remains are often associated with ancestral spirits and are thus taboo — understandably, Bedford emphasized to me, explaining that he wouldn’t be comfortable digging up and boring into “Granddad.” But in this case, the ni-Vanuatu expressed no reservations: Local oral traditions contained no sacred reference to the Teouma dead, and Chief Alben gave his blessing. One of Bedford’s colleagues opened the skulls in a workshop warren behind the national museum, extracted the nubbins of petrous bone and shipped them to Dublin, where they were sandblasted. There turned out to be DNA in three of the samples. It was the first to be found in the tropics and suggested the opening of wide new fronts in ancient-DNA research.
The skulls of Teouma were particularly interesting to paleogenomicists not only because they produced the first ancient DNA in the Pacific but because their genetic evidence could be brought to bear on an outstanding debate in the region. The pivotal moment in Pacific archaeological history happened in 1952, when a team of researchers found a cache of dentate-stamped pots at a place called Lapita in New Caledonia, a French collectivity to the southwest of Vanuatu. More than 200 sites eventually turned up nearly duplicate versions of this innovation across an enormous span of the region. The pots were often found with particular varieties of preserved plants and nuts, as well as stone adzes. Whoever made those pots some 3,000 years ago had traveled across more than 2,000 miles of ocean — from near Papua New Guinea to Tonga and Samoa — in perhaps as little as 10 generations. As Patrick V. Kirch, the dean of American archaeology in the Pacific, once put it, “Without a doubt, the Lapita colonization of Remote Oceania ranks as one of the great sagas of world prehistory.”	The skulls of Teouma were particularly interesting to paleogenomicists not only because they produced the first ancient DNA in the Pacific but because their genetic evidence could be brought to bear on an outstanding debate in the region. The pivotal moment in Pacific archaeological history happened in 1952, when a team of researchers found a cache of dentate-stamped pots at a place called Lapita in New Caledonia, a French collectivity to the southwest of Vanuatu. More than 200 sites eventually turned up nearly duplicate versions of this innovation across an enormous span of the region. The pots were often found with particular varieties of preserved plants and nuts, as well as stone adzes. Whoever made those pots some 3,000 years ago had traveled across more than 2,000 miles of ocean — from near Papua New Guinea to Tonga and Samoa — in perhaps as little as 10 generations. As Patrick V. Kirch, the dean of American archaeology in the Pacific, once put it, “Without a doubt, the Lapita colonization of Remote Oceania ranks as one of the great sagas of world prehistory.”
Where had this “Lapita” culture come from, and who were the people associated with it? Over the last 50 years, a collaboration among archaeologists, linguists, botanists, ecologists, geologists and more had produced some form of consensus. A population of early farmers departed from Taiwan about 5,000 years ago, with the help of the newly developed outrigger canoe. They moved down through the Philippines and the Spice Islands, along the northern coasts of New Guinea and eventually out to the Bismarck Archipelago, more or less the limit of Near Oceania; the “tracer dye” for their path was the language family they left behind, one known as Austronesian. Along the way, they encountered populations of “Papuans” — a generic shorthand for highly distinct groups of people who had been in the Papua New Guinea region for 40,000 years. The interactions between the incoming “Austronesians,” another shorthand for whoever was presumably spreading those languages, and the indigenous Papuans created the constellation of practices that would become known as Lapita. Finally, the people now associated with Lapita sailed into the blankness of the open ocean for the first time, crossing the Remote Oceania divide to Vanuatu and, from there, outward to the farthest reaches of the Pacific.	Where had this “Lapita” culture come from, and who were the people associated with it? Over the last 50 years, a collaboration among archaeologists, linguists, botanists, ecologists, geologists and more had produced some form of consensus. A population of early farmers departed from Taiwan about 5,000 years ago, with the help of the newly developed outrigger canoe. They moved down through the Philippines and the Spice Islands, along the northern coasts of New Guinea and eventually out to the Bismarck Archipelago, more or less the limit of Near Oceania; the “tracer dye” for their path was the language family they left behind, one known as Austronesian. Along the way, they encountered populations of “Papuans” — a generic shorthand for highly distinct groups of people who had been in the Papua New Guinea region for 40,000 years. The interactions between the incoming “Austronesians,” another shorthand for whoever was presumably spreading those languages, and the indigenous Papuans created the constellation of practices that would become known as Lapita. Finally, the people now associated with Lapita sailed into the blankness of the open ocean for the first time, crossing the Remote Oceania divide to Vanuatu and, from there, outward to the farthest reaches of the Pacific.
Archaeologists differed, often bitterly, on the details, but as Reich describes it in his book, the prevailing opinion was that “the Lapita archaeological culture was forged during a period of intense exchange between people ultimately originating in the farming center of China (via Taiwan) and New Guineans.” This certainly made intuitive sense. The people of contemporary Vanuatu are black, like the Papuan people of New Guinea, but they speak Austronesian languages that can ultimately be traced to Asia. Reich believed that the existing consensus was the perfect sort of hypothesis to put to the ancient-DNA test. The Austronesians and the Papuans had been separated by at least 40,000 years of genetic differentiation, which meant that it would be very easy to discriminate by genetic signature. Would the samples taken from the skulls at Teouma show a closer relationship to the people of nearby Papua or the people of distant Asia?	Archaeologists differed, often bitterly, on the details, but as Reich describes it in his book, the prevailing opinion was that “the Lapita archaeological culture was forged during a period of intense exchange between people ultimately originating in the farming center of China (via Taiwan) and New Guineans.” This certainly made intuitive sense. The people of contemporary Vanuatu are black, like the Papuan people of New Guinea, but they speak Austronesian languages that can ultimately be traced to Asia. Reich believed that the existing consensus was the perfect sort of hypothesis to put to the ancient-DNA test. The Austronesians and the Papuans had been separated by at least 40,000 years of genetic differentiation, which meant that it would be very easy to discriminate by genetic signature. Would the samples taken from the skulls at Teouma show a closer relationship to the people of nearby Papua or the people of distant Asia?
In October 2016, the paper — with such well-regarded Pacific archaeologists as Stuart Bedford and his mentor, Matthew Spriggs of the Australian National University, among the 31 authors — was published in Nature as “Genomic Insights Into the Peopling of the Southwest Pacific.” The analysis of ancient DNA from three 3,000-year-old skulls from Teouma, along with one skull dated a few hundred years later from Tonga, appeared to provide unambiguous confirmation of Lapita heritage. The First Remote Oceanians, as the paper calls them, were not, after all, a heterogenous group; they were of unmixed Asian descent.	In October 2016, the paper — with such well-regarded Pacific archaeologists as Stuart Bedford and his mentor, Matthew Spriggs of the Australian National University, among the 31 authors — was published in Nature as “Genomic Insights Into the Peopling of the Southwest Pacific.” The analysis of ancient DNA from three 3,000-year-old skulls from Teouma, along with one skull dated a few hundred years later from Tonga, appeared to provide unambiguous confirmation of Lapita heritage. The First Remote Oceanians, as the paper calls them, were not, after all, a heterogenous group; they were of unmixed Asian descent.