Who We Are And How We Got Here - Part 3 - Europe

Modern Europe is the product of multiple migrations

Paleolithic Europe

Europe is probably the best-studied region in the world for ancient DNA. This is because many of the scientific techniques were first discovered here. In addition, there is an abundance of Paleolithic sites to draw material from including Goyet Caves, Oase Cave, Bacho Kiro Caves, Kostenki-12, Halstatt, and Dolní Věstonice, among many others.

The stone age cultures of Europe are grouped by archaeologists into a number of cultures based on the styles of their tools (“industries”) and other artifacts such as carvings, jewelry and cave paintings. Often they are named after places in France where their fossils were first discovered (e.g. Aurignacian, Gravettian, Soultrean, Magdalenian, etc.). These were hunter-gatherers who preyed on the large animals of Ice Age Europe such as reindeer, woolly mammoths and mastodons.

Following the glacial retreat and gradual warming of the climate a number of Mesolithic cultures emerged in Europe, followed by Neolithic cultures centered around farming and pastoralism. These cultures are often named after the distinctive styles of pottery found in their burials (e.g. Globular Amphora, Funnelbeaker, Pitted Ware, Linear Ware, Corded Ware, Bell Beaker, etc.). Cultures further east in central Asia and the Caucasus are often named after the geographic location where their artifacts were first discovered.

David Reich and company divide the initial peopling of Europe during the Paleolithic into five sequential "events" corresponding to climatic changes and geological upheavals:

1. The most ancient inhabitants of Europe were the very first Homo sapiens to enter the continent between forty-five to fifty thousand years ago (barring anomalies like the 210,000 year old Apidima Skull from Greece). Sometimes these people are referred to as "Cro-Magnons," although this term has mostly fallen out of favor. These people apparently interacted and interbred with the Neanderthals already living in Europe at the time, however they appear to have died out and not left any descendants. Recently it's been discovered that the two groups lived alongside one another for longer than previously thought.

The eruption of a supervolcano in the Italian Peninsula near what is today Naples around 39,000 years ago appears to have put enough ash into the upper atmosphere to have created a "nuclear winter"-type effect. The ash from this eruption is deposited in a layer across Eurasia. The climate became much colder. Very few Neanderthal remains are found above this layer indicating that it might have played a significant role in their demise. But it also had an an effect on the earliest modern humans in Europe as well: "Most modern human archaeological cultures that left remains below the ash layer left none above it. Many modern humans disappeared as dramatically as their Neanderthal contemporaries." (p. 90)

2. After 39,000 years ago another human culture emerged in Europe who made stone tools archaeologists refer to as Aurignacian. This population appears to have descended from a single ancestral population based on the similarities between DNA samples across Europe. These include a 37,000 year old fossil from present-day Russia and a 35,000 year old fossil from the Goyet Caves in present-day Belgium. They also made the earliest cave paintings, such as Chauvet Cave in France and Altamira in Spain. This population did contribute some ancestry to later Europeans.

3. Then, between 33,000 years ago and 22,000 years ago, another hunter-gatherer culture emerged in Europe who made tools and artifacts archaeologists call Gravettian. The Gravettian culture is associated with the carved stone "Venus" figurines. They lived during a particularly cold period in Europe.

The Gravettian culture was more deliberate about burying their dead which means we have more fossils from this culture than from earlier ones. They appear to have entered Europe from somewhere in the East along the Danube corridor and displaced the previous Aurignacian inhabitants. Fossils from Germany, France, Belgium, Italy and the Czech Republic all show genetic similarities indicating that this Gravettian culture was a distinct group of people descending from a common ancestral source population. At the Goyet Caves in Belgium, Gravettian tools and DNA supplant earlier Aurignacian ones. The Gravettian culture appears to have been the last unified culture of the Paleolithic.

4. Expanding ice sheets over Northern Europe pushed the inhabitants of the continent south between 19,000 and 14,000 years ago—a climatic period known as the Oldest Dryas. In southwestern Europe a new culture emerged with a distinctive toolkit archaeologists call Magdalenian.

An analysis of a 19,000 year-old individual found in Spain indicated that the Magdalenian people were genetically related to the people of the Aurginacian culture who lived in northern Europe 20,000 years earlier. The Magdalenian culture expanded northward out of southeastern Europe when the ice sheets began to retreat after the Last Glacial Maximum.

5. After 14,000 years ago there was a warming period called the Bølling–Allerød interstadial. During this period the alpine glacial wall that divided West and East Europe finally melted. The people who had waited out the Ice Age in southern Europe became dominant across the entire European continent following the melting of the glacial wall. After this event, the peoples of Europe and the Near East become more genetically similar. Genetics show that people who lived in Europe after 14,000 years ago share more genetic affinity with contemporary Near Eastern peoples than with the earlier Madgalenian people.

The reason for this is unclear. It’s possible that European hunter-gathers migrated out of Europe into an Anatolian refugium during the coldest portions of the Last Glacial Maximum. From there they may have radiated outward back into both Europe and the Near East as the climate warmed: “Perhaps these same people also expanded east into Anatolia, and their descendants spread farther to the Near East, bringing together the genetic heritages of Europe and the Near East more than five thousand years before farmers spread Near Eastern ancestry back into Europe by migrating in the opposite direction.” (pp. 92-93)

The West Eurasians

Today the peoples of Europe, the Near East, and Central Asia are all genetically very similar. The evidence indicates that as populations expanded over the course of thousands of years following the adoption of farming they effectively "blended" into one another becoming more genetically homogeneous. The trend since farming began—and increasing since the Bronze Age—has been for more mixing and less genetic diversity. This blended population is known as West Eurasians. The West Eurasians, then, are a mixture of farmers and hunter-gatherers and retain phenotypic characteristics of both.

By studying the fossils from populations across the ancient Near East during this period, it’s possible to get a snapshot of these first farmers. Prior to farming the disparate populations inhabiting the ancient Near East were very genetically distinct from one another—as distinct as Western Europeans and East Asians are today. That is, the first groups to take up farming were very genetically distinct populations, meaning that that there was no single ancestral "farming" population which displaced all the others. Rather, farming and herding were taken up more-or-less simultaneously by a number of different groups throughout Western Asia after 10,000 years ago.

...about ten thousand years ago there were at least four major populations in West Eurasia—the farmers of the Fertile Crescent, the farmers of Iran, the hunter-gatherers of central and western Europe, and the hunter-gathers of Eastern Europe. All these populations differed from each other as much as Europeans differ from East Asians today. Scholars interested in trying to create ancestry-based racial classifications, had they lived ten thousand years ago, would have categorized these groups as "races," even though none of these groups survives in unmixed form today.

Spurred by the revolutionary technology of plant and animal domestication, which could support much higher population densities than hunting and gathering, the farmers of the Near East began migrating and mixing with their neighbors. But instead of one group displacing all the others and pushing them to extinction, as had occurred in some of the previous spreads of hunter-gatherers in Europe, in the Near East all the expanding groups contributed to later populations.

The farmers in present-day Turkey expanded into Europe. The farmers in present-day Israel and Jordan expanded into East Africa, and their genetic legacy is greatest in present-day Ethiopia. Farmers related to those in present-day Iran expanded into India as well as the steppe north of the Black and Caspian seas.

They mixed with local populations there and established new economies based on herding that allowed the agricultural revolution to spread into parts of the world inhospitable to domesticated crops. The different food-producing populations also mixed with one another, a process that was accelerated by technological developments in the Bronze Age after around five thousand years ago...(pp. 95-96)

As I noted last time, several of these early farming populations derived a great deal of ancestry from the Basal Eurasian ghost population. Therefore, the proportion of Neanderthal DNA present in these groups is quite low.

It is clear from the genetics that these distinct populations no longer exist in any form today due to blending, and thus there are no "pure" populations anywhere in Europe or Western Asia: “By demonstrating that the genetic fault lines in West Eurasia between ten thousand and four thousand years ago were entirely different from those today, the ancient DNA revolution has shown that…today's divisions are relatively recent phenomena, with their origin in repeated mixtures and migrations…Mixture is fundamental to who we are, and we need to embrace it, not deny that it occurred.” (p. 97)

First farmers had diverse origins, DNA shows (BBC)

Neolithic Europe

After around 8,000 years ago, farming populations started migrating westward into Europe from Anatolia—modern-day Turkey. This population is referred to by geneticists as the Early European Farmers (EEF) or sometimes Early Anatolian Farmers (EAF).

This population spread from the Balkans to the Iberian peninsula in the west and Germany to the north, retaining roughly 90 percent of their DNA, indicating that they did little interbreeding with the indigenous hunter-gatherer populations along the way. This migration is documented by the spread of a distinctive style of pottery, known as the Linear Pottery culture, or LBK culture (from the German Linearbandkeramik). In just a few generations the LBK culture swarmed across southern and central Europe, pushing the native hunter-gatherers to the margins. The LBK culture featured highly developed food production techniques centered around wheat and cattle.

Traveling rapidly westward across the fertile plains of what is now Germany, the LBK farmers reached the Rhine within just a few centuries, around 7,300 years ago. Fine-grained analysis of the evolution of pottery styles, along with radiocarbon dating, suggests that they practiced a form of leapfrog colonization. They took “stepwise movements with sometimes hundreds of kilometers covered, and then the landscape in between filled up,” says archaeologist Detlef Gronenborn...At some point they learned how to smelt copper, and a trade in precious copper objects sprang up between farming communities.

On the southern route, the farmers leapfrogged along the Mediterranean coast from Italy to France and on to the Iberian Peninsula. After reaching French shores, 7,800 or so years ago, they migrated northward toward the Paris Basin, the plain between the Rhine and the Atlantic Ocean that forms a kind of continental cul-de-sac. It was there that the two great streams of farmers met, around seven millennia ago. By then their cultures had diverged to some extent—they had been separated for more than 500 years—but they would still have recognized their own kind. They mingled both biologically and culturally.

When the First Farmers Arrived in Europe, Inequality Evolved (Scientific American)

Today, the population that retains the greatest amount of EEF ancestry are the inhabitants of Sardinia, an island in the Mediterranean Sea, indicating that at least some of these migrations must have been by boat. However, genetics also showed that the earliest farmers of the Peloponnese in southern Greece were related to a different set of Anatolian migrant farmers—ones who were more closely related to ancient Iranians. Perhaps this was the source of the distinctive Spartan culture which even other Greeks found to be unusual?

We also found that farmers from the Peloponnese in southern Greece who lived around six thousand years ago may have derived part of their ancestry from a different source population in Anatolia—a population that descended more from Iranian-related populations than was the case in the northwestern Anatolian farmers who were a likely source population for the rest of Europe's farmers.

The first farming in Europe was practiced in the Peloponnese and the nearby island of Crete by people who did not use pottery. This has led some archaeologists to wonder if they were from a different migration. Our ancient DNA is consistent with this idea, and suggests the possibility that this population held on for thousands of years. (p. 105)

Early European Farmers living between 6,000 and 4,500 years ago show as much as 20 percent of their DNA being derived from indigenous European hunter-gatherers. This indicated that the farming and foraging populations in Europe had remained separate from one another for thousands of years but after 6,000 years ago began mixing more freely. This meant that "pure" European Hunter Gatherer populations gradually began assimilating into the neighboring farming cultures, with the farmers contributing the largest amount to the subsequent gene pool.

In northern Europe, the EEF bumped up against native Neolithic cultures like the Funnelbeaker culture (or TBK culture, from German Trechterbekercultuur). This was the culture that constructed the great stone megaliths of northwest Europe. The natives of the far north began to incorporate farming techniques while retaining many aspects of their previous hunter-gatherer lifestyle. As farming techniques more suited to northern ecologies were gradually developed by these cultures, gene flow became more pronounced between northern and southern Europe:

The Funnel Beaker culture arose in a belt of land a few hundred kilometers from the Baltic Sea, which was not reached by the first wave of farmers, probably because their methods were not optimized for the heavy soils of northern Europe. Protected by the stronghold of their difficult-to-farm environment, and sustained by the fish and game resources of Baltic Europe, the northern hunter-gatherers had more than a thousand years to adapt to the challenges of farming. They adopted domesticated animals, and later crops, from their southern neighbors, but kept many elements of their hunter-gathering ways.

The people of the Funnel Beaker culture were among those who built megaliths, the collective burial tombs made of stones so large it would have taken dozens of people to move them. The archaeologist Colin Renfrew suggested that megalith building might be a direct reflection of this boundary between southern farmers and hunter-gatherers turned farmers—a way of laying claim to territory, of distinguishing one people and culture from others.

The genetic data may bear witness to this interaction, as there was clearly a stream of new migrants into the mixed population. Between six thousand and five thousand years ago, most of the northern gene pool was overtaken by farmer ancestry, and it was this mixture of a modest amount of hunter-gatherer related ancestry and a large amount of Anatolian farmer-related ancestry—in a population that retained key elements of hunter-gatherer culture—that characterized the Funnel Beaker potters and many other contemporary Europeans. (p. 106)

The original inhabitants of Neolithic Europe, then, derived from these two populations: West European Hunter-Gatherers (WHG) and Early European Farmers (EEF). Western Hunter Gatherers tended to have dark skin, dark hair and blue eyes. Early European farmers tended to have lighter skin and dark hair and eyes. Southern Europeans (like Italians and Greeks) tend to have a greater percentage of EEF ancestry, whereas northern Europeans (like Germans and Swedes) have a greater share of WHG ancestry. This contributes, for example, to height differences seen today between southern and northern Europeans.

Stonehenge: DNA reveals origin of builders (BBC)

The Western Steppe Herders

The final contribution to the genetic makeup of modern Europeans was made by a group known to geneticists as Western Steppe Herders (WSH) or Western Steppe Pastoralists. The Western Steppe Herders are a large genetic/cultural grouping which encompasses a number of nomadic pastoralist groups originating in the vast grassy plains bordering the Black and Caspian seas including Khvalynsk, Sredny Stog, Repin, Yamnaya, Fatyanovo-Balanovo, Usatovo, Poltavka, Catacomb, and a number of other cultures.

Around 5,000 years ago a Copper-Age culture known as the Yamnaya, or Yamna culture (from a Russian adjective meaning "related to pits"), became the predominant culture on the steppe. Only a hundred years later they reached the forested areas of Europe where they mixed with the Stone Age farmers who inhabited this region and established what is known to archaeologists as the Corded Ware culture, an archaeological horizon whose distinctive pottery features cord-like impressions in the clay. The Corded Ware culture spread westward into Europe starting around 4,900 years ago. Genetic evidence has shown that individuals associated with the Corded Ware culture feature around 75 percent WSH ancestry, with about 10-18 percent European Farmer ancestry.

Today WSH represents the largest single portion of ancestry for Europeans north of the Alps, with Norwegians having the highest amount. The Y-signature is especially dominant, with all previous native European Y-haplogroups practically dying out. This has caused speculation that these migrants were mostly men who married local women along the way. The steppe herders appear to have first introduced blond hair and pale skin phenotypes into the European gene pool.

Steppe migrant thugs pacified by Stone Age farming women (Science Daily)

The Yamnaya herders were themselves a mixture of Eastern European Hunter-gatherers (EHG) and Caucasian Hunter Gatherers (CHG). The connection to the Caucasus Mountains is particularly revealing, since the Yamnaya people appear to have inherited a number of their cultural traditions from an earlier culture in this region known as the Maikop (or Maykop) culture, including burial mounds (kurgans) and the use of wheeled vehicles. The Maikop culture, in turn, may have its origins further south in the Iranian plateau or perhaps some other part of the Caucasus. The Maikop culture is contemporaneous with the Uruk period in Mesopotamia.

Our ancient DNA data also allowed us to learn how the Yamnaya themselves had formed from earlier populations.

From seven thousand until five thousand years ago, we observed a steady influx into the steppe of a population whose ancestors traced their origin to the south—as it bore genetic affinity to ancient and present-day people of Armenia and Iran—eventually crystallizing in the Yamnaya, who were about a one-to-one ratio of ancestry from these two sources.

A good guess is that the migration proceeded via the Caucasus isthmus between the Black and Caspian seas. Ancient DNA data...have shown that the populations of the northern Caucasus had ancestry of this type continuing up until the time of the Maikop culture, which just preceded the Yamnaya.

The evidence that people of the Maikop culture of the people who preceded them in the Caucasus made a genetic contribution to the Yamnaya is not surprising in light of the cultural influence the Maikop had on the Yamnaya. Not only did the Maikop pass on to the Yamnaya their technology of carts, but they were also the first to build the kurgans that characterized the steppe cultures for thousands of years afterward.

The penetration of Maikop lands by Iranian- and Armenian-related ancestry from the south is also plausible in light of studies showing that Maikop goods were heavily influenced by elements of the Uruk civilization of Mesopotamia to the south, which was poor in metal resources and engaged in trade and exchange with the north as reflected in Uruk goods found in settlements of the northern Caucasus. Whatever cultural process allowed the people from the south to have such a demographic impact, once the Yamnaya formed, their descendants expanded in all directions... (pp. 108-109)

The Yamnaya were a highly mobile people who lived in wagons pulled by horses and herded livestock. Horses appear to have been a cultural adaptation, as there is no evidence of genetic admixture with the Botai culture further east (who were more closely related to the Ancient North Eurasians). Yamnaya culture is distinguished by their distinctive burial mounds, known as kurgans, where individuals were elaborately buried with bronze vessels, horses, and weaponry (hence alternative names for this culture such as the Kurgan culture, the Pit Grave culture, or the Battle-Axe culture).

Beginning around forty-nine hundred years ago, artifacts characteristic of the Corded Ware culture started spreading over a vast region, from Switzerland to European Russia. The ancient DNA data showed that beginning with the Corded Ware culture, individuals with ancestry similar to present-day Europeans first appeared in Europe...

The genetic data thus settled a long-standing debate in archaeology about linkages between the Corded Ware and the Yamnaya cultures. The two had many striking parallels, such as the construction of large burial mounds, the intensive exploitation of horses and and herding, and a strikingly male-centered culture that celebrated violence, as reflected in the great maces (or hammer-axes) buried in some graves.

At the same time, there were profound differences between the two cultures, notably the entirely different types of pottery that they made, with important elements of the Corded Ware style adapted from previous central European pottery styles. But the genetics showed that the connection between the Corded Ware culture and the Yamnaya culture reflected major movements of people. The makers of Corded Ware culture were, at least in a genetic sense, a westward extension of the Yamnaya. (p. 110)

The most violent group of people who ever lived (Daily Mail)

The Bell Beaker Culture

As the Corded Ware culture swept into Europe from the east, another culture began spreading around Europe from the west starting around 4,700 years ago. It's known as the Bell Beaker culture, after their distinctive bell-shaped pottery. The "beaker folk" appear to have originated in the Iberian peninsula (modern-day Spain) and spread northward and eastward over the next several centuries.

The question for archaeologists studying the expansion of the Bell Beaker culture was once again whether it was a product of migration or cultural diffusion.

Genetic evidence indicated that the answer was both. In Spain, where the culture originated, there is no genetic difference between the Beaker folk and those who immediately preceded them. In central Europe, on the other hand, the Beakers were not related to the Iberians at all, but rather to the Yamnaya, with around 50 percent Western Steppe Herder ancestry. That is, the eastern Beakers were a western extension of the Yamnaya who had voluntarily adopted the Beaker tradition, perhaps due to cultural assimilation or stylistic choice: “…the Bell Beaker culture could be viewed as a kind of ancient religion that converted peoples of different backgrounds to a new way of viewing the world, thus serving as an ideological solvent that facilitated the integration and spread of steppe ancestry and culture into central and western Europe.” (p. 116)

The"Yamnaya Beakers" began moving westward—including back into Iberia. They migrated into the British Isles around 4,500 years ago, possibly after picking up sailing technology from the Iberians. It's thought that this expansion is associated with the initial spread of the Celtic languages in Europe. The later Iron Age Halstatt and La Tène cultures show genetic continuity with the Bell Beaker culture, with about 50 percent WSH ancestry.

At the beginning of the twentieth century, the recognition of the massive impact of the Bell Beaker culture led to the romantic notion of a "Beaker Folk," a people who disseminated a new culture and perhaps Celtic languages—a nod to the nationalistic fervor of the time. But, like the claim made for the Corded Ware culture, this position fell out of favor after the Second World War.

...individuals in Iberia were genetically indistinguishable from the people who had preceded them and who were not buried in a Bell Beaker culture style. But Bell Beaker-associated individuals in central Europe were extremely different, with most of their ancestry of steppe origin, and little if any ancestry in common with individuals from Iberia associated with Bell Beaker culture.

So, in contrast to what happened with the spread of Corded Ware culture from the east, the initial spread of the Bell Beaker culture across Europe was mediated by the movement of ideas, not migration. Once the Bell Beaker culture reached central Europe through the dispersal of ideas, though, it spread further through migration… (pp. 114-115)

The expansion of the Bell Beaker culture into the British Isles—in contrast to the rest of the continent—was caused by population replacement rather than cultural diffusion. The Beaker people replaced 90% of the indigenous population of Britain—the people who built Stonehenge—within just a few hundred years. They also brought with them metalworking and the ability to digest milk.

Ancient mass migration transformed Britons' DNA (BBC)

Measured in terms of its proportion of steppe ancestry, DNA extracted from dozens of Bell Beaker skeletons in Britain closely matches that of skeletons from Bell Beaker culture graves across the English Channel…British and Irish skeletons from the Bronze Age that followed the Beaker period had at most around 10 percent ancestry from the first farmers of these islands, with the other 90 percent from people like those associated with the Bell Beaker culture in the Netherlands. This was a population replacement at least as dramatic as the one that accompanied the spread of the Corded Ware culture. (p. 115)

The Indo-European Languages

The Corded Ware culture has also been associated with the spread of the spread of the Indo-European languages. Today Indo-European languages are the most widespread language family on earth due to migration and colonialism.

Initially, it was thought that Indo-European language family originated in Anatolia (Turkey) and was introduced into Europe with the arrival of the Early Anatolian Farmers—known as the Anatolian hypothesis. The earliest known Indo-European languages come from Anatolia, including Hittite and related language called Luwian. These were the first Indo-European languages to be written down.

But recent genetic evidence has given weight to the idea that the Indo-European languages instead originated somewhere on the Pontiac-Caspian steppe and spread into Europe via the Corded Ware migrations. The Corded Ware culture traveled both east and west, spreading these languages to both to Europe and South Asia. An eastward migration of the Corded Ware culture back into the steppe is thought to have created the Sintashta culture, which subsequently contributed ancestry to the inhabitants of modern-day India, Pakistan and Iran, as we'll see next time. This theory is known as the Steppe hypothesis.

Many cultural similarities have been documented between Iron Age European cultures and Indian cultures whose members speak an Indo-European language. Words related to wheeled carts, horses, cattle, and particular deities are especially similar between these widely dispersed languages.

[Archaeologist David Anthony's] key observation is that all extant branches of the Indo-European language family except for the most anciently-diverging Anatolian ones (such as ancient Hittite) have an elaborate shared vocabulary for wagons, including words for axle, harness, pole, and wheels. Anthony interpreted this sharing as evidence that all Indo-European languages spoken today, from India in the east to the Atlantic fringe in the west, descend from a language spoken by an ancient population that used wagons.

This population could not have lived much earlier than about six thousand years ago, since we know from archaeological evidence that it was around then that wheels and wagons spread. This date rules out the Anatolian farming expansion into Europe between nine thousand and eight thousand years ago.

The obvious candidate for dispersing most of today's Indo-European languages is thus the Yamnaya, who depended on the technology of wagons and wheels that became widespread around five thousand years ago. (pp. 119-120)

However, early Anatolian languages like Hittite use different words for horses, wagons and wheels (and agriculture) than other Indo-European languages. This indicates that the Hittite and Luwian languages must have broken off from proto-Indo-European sometime before the adoption of wheeled carts and horses by the ancestors of the Yamnaya.

This raises the possibility that the ultimate origin for the Indo-European languages may not actually be the Pontic steppe, but an altogether different region whose inhabitants contributed genes (and language) both to Iron Age Anatolians (such as the Hittites) and Western Steppe Herders (such as the Yamnaya). Unfortunately, the Hittites typically cremated their dead rather than burying them complicating verification of this possibility through genetics.

Anatolian languages known from four-thousand-year-old tablets recovered from the Hittite Empire and neighboring ancient cultures did not share the full wagon and wheel vocabulary present in all Indo-European languages spoken today. Ancient DNA evidence available from this time in Anatolia shows no evidence of steppe ancestry similar to that in the Yamnaya (although the evidence here is circumstantial as no ancient DNA from the Hittites themselves has yet been published).

This suggests to me that the most likely location of the population that first spoke an Indo-European language was south of the Caucasus Mountains, perhaps in present-day Iran or Armenia, because ancient DNA from people who lived there matches what we would expect from a source population both for the Yamnaya and for ancient Anatolians.

If this scenario is right, the population sent one branch up into the steppe—mixing with steppe hunter-gatherers in a one-to-one ratio to become the Yamnaya as described earlier—and another to Anatolia to found the ancestors of people there who spoke languages such as Hittite. (p. 120)

Intriguingly, the Basque language of Spain is one of the only non-Indo-European languages spoken today in Western Europe, and it has no clear relationship to any other languages. Genetic studies show a distinct lack of Western Steppe Herder ancestry in the Basque population—unlike in other parts of Spain—indicating that their language may be a descendant of the language spoken by the original neolithic farmers of Europe.

Ancient DNA cracks puzzle of Basque origins (BBC)

The Lithuanian archaeologist Marija Gimbutas claimed that the culture of what she referred to as "Old Europe" was mostly non-violent and centered on the worship of various goddesses (e.g. “The Civilization of the Goddess”). She argued that the cultures of Old Europe were gynocentric, with women enjoying high status and a great deal of autonomy. She also thought they had a fairly flat social hierarchy as indicated by communal (rather than individual) burials. She pointed to the similarities in goddess figurines found in both Anatolia and early Neolithic Europe, along with a distinct lack of fortifications or other signs of violent conflict, and as evidence of this.

All that changed, she said, after the arrival of the Kurgan culture from the steppes which displaced the peaceful, female-centric (“matristic”) cultures of Old Europe in the late Bronze Age. This culture, she claimed, was violent, patriarchal (“andocratic”), stratified, and worshiped male deities associated with the sky and battle. This was reflected in burial customs, for example, where communal burials were supplanted by the internment of powerful chieftains in tumuli with weapons and horses. Fortifications known as hillforts begin to appear around this time—along with the first evidence of massacres—in the archaeological record. Although widely treated with skepticism at the time, many of her claims have since been backed up by the genetic evidence.

How did the Western Steppe Herders make such an overwhelming demographic impact, to the point of almost total population replacement in some areas? Some have raised the possibility of an ancient genocide. But a more recent theory points to the role of disease. It's possible that the people of the steppe may have introduced new diseases into Europe causing a massive die-off of the native population. This speculation was fueled by the discovery of the Yersinia pestis bacterium in burials of people interred in Europe around the time of steppe herder infiltration—the same bacterium which caused the Black Death thousands of years later.

Eske Willerslev and Simon Rasmussen, working with the archaeologist Kristian Kristiansen, had the idea of testing 101 ancient DNA samples from Europe and the steppe for evidence of pathogens. In seven samples, they found DNA from Yersinia pestis, the bacterium responsible for the Black Death, estimated to have wiped out around on-third of the populations of Europe, India, and China around seven hundred years ago. Traces of plague in a person's teeth are almost a sure sign that he or she died of it.

The earliest bacterial genomes that they sequenced lacked a few key genes necessary for the disease to spread via fleas, which is necessary to cause bubonic plague. But the bacterial genomes did carry the genes necessary to cause pneumonic plague, which is spread by sneezing and coughing just like the flu. That a substantial fraction of random graves analyzed carried Y. pestis shows that this disease was endemic on the steppe. (p. 113)

Modern Europeans, then, are a mixture of three primary "tribes": West European Hunter-Gatherers (WHGs); Early Anatolian Farmers (EEFs); and Western Steppe Herders (WSHs), in various proportions.

NEXT: Ancient India