Thanks to the ancient DNA revolution, we now know that Neolithic farmers spread much deeper into Europe demographically than was previously thought (back in 1993 by Luca Cavalli-Sforza and his colleagues):
Cavalli-Sforza was especially interested in interpreting the genetic clusters among present-day people in terms of population history. He and his colleagues analyzed their blood group data by using a technique that identifies combinations of biological variations that are most efficient at summarizing differences across individuals. Plotting these combinations of blood group types onto a map of West Eurasia, they found that the one summarizing the most variation across individuals reached its extreme value in the Near East, and declined along a southeast-to-northwest gradient into Europe. They interpreted this as a genetic footprint of the migration of farmers into Europe from the Near East, known from archaeology to have occurred after nine thousand years ago. The declining intensity suggested to them that after arriving in Europe, the first farmers mixed with local hunter-gatherers, accumulating more hunter-gatherer ancestry as they expanded, a process they called "demic diffusion." Until recently, many archaeologists viewed the demic diffusion model as an exemplary merging of insights from archaeology and genetics.
The model that Cavalli-Sforza and colleagues proposed to describe the data was intellectually attractive, but it was wrong. Its flaws became apparent beginning in 2008, when John Novembre and colleagues demonstrated that gradients like those observed in Europe can arise without migration. They then showed that a Near Eastern farming expansion into Europe might counter-intuitively cause the mathematical technique that Cavalli-Sforza used to produce a gradient perpendicular to the direction of migration, not parallel to it as had been seen in the real data.
It took the revolution wrought by the ability to extract DNA from ancient bones — the "ancient DNA revolution" — to drive a nail into the coffin of the demic diffusion model. The ancient DNA revolution documented that the first farmers even in the most remote reaches of Europe — Britain, Scandinavia, and Iberia — had very little hunter-gatherer-related ancestry. In fact, they had less hunter-gatherer ancestry than is present in diverse European populations today. The highest proportion of early farmer ancestry in Europe is today not in Southeast Europe, the place where Cavalli-Sforza thought it was most common based on the blood group data, but instead is in the Mediterranean island of Sardinia to the west of Italy.
Compare the early estimates of Anatolian farmer ancestry in Europe to the more accurate estimates of today:
It's still a bit lower in Northern Europe, but that's because it was displaced by a group of pastoralists from the Russian steppe called Yamnaya who arrived even later (less than 5000 years ago during the Bronze Age) and had a lot of another kind of Middle Eastern ancestry (from the Caucasus/Iran) plus a component from way out in Siberia called Ancient North Eurasian that's related to Native American Indians:
The extraordinary fact that emerges from ancient DNA is that just five thousand years ago, the people who are now the primary ancestors of all extant northern Europeans had not yet arrived.
The Tide from the East
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The Yamnaya emerged from previous cultures of the steppe and its periphery and exploited the steppe resources far more effectively than their predecessors. They spread over a vast region, from Hungary in Europe to the foothills of the Altai Mountains in central Asia, and in many places replaced the disparate cultures that had preceded them with a more homogeneous way of life.
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Our analysis of DNA from the Yamnaya — led by Iosif Lazaridis in my laboratory — showed that they harbored a combination of ancestries that did not previously exist in central Europe. The Yamnaya were the missing ingredient, carrying exactly the type of ancestry that needed to be added to early European farmers and hunter-gatherers to produce populations with the mixture of ancestries observed in Europe today. 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.
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...the frequencies of mutations in northern Europeans today tend to be intermediate between those of southern Europeans and Native Americans. He hypothesized that these findings could be explained by the existence of a "ghost population" — the Ancient North Eurasians — who were distributed across northern Eurasia more than fifteen thousand years ago and who contributed both to the population that migrated across the Bering land bridge to people the Americas and to northern Europeans. A year later, Eske Willerslev and colleagues obtained a sample of ancient DNA from Siberia that matched the predicted Ancient North Eurasians—the Mal'ta individual whose skeleton dated to around twenty-four thousand years ago.
How could the finding of an Ancient North Eurasian contribution to present-day northern Europeans be reconciled with the two-way mixture of indigenous European hunter-gatherers and incoming farmers from Anatolia that had been directly demonstrated through ancient DNA studies? The plot became even thicker as we and others obtained additional ancient DNA data from hunter-gatherers and farmers between eight thousand and five thousand years ago and found that they fit the two-way mixture model without any evidence of Ancient North Eurasian ancestry. Something profound must have happened later — a new stream of migrants must have arrived, introducing Ancient North Eurasian ancestry and transforming Europe.
What's most ironic is that it's actually all the later "non-European" Middle Eastern ancestry, including a component called Basal Eurasian, that made Europeans become "more European" (i.e. more Caucasoid, i.e. "whiter") and more homogeneous than they would have been, because the original Paleolithic hunter-gatherers, like Ancient North Eurasians, actually had affinities to East Asians:
Lazaridis was trying to understand a peculiar Four Population Test result showing that East Asians, present-day Europeans, and pre-farming European hunter-gatherers from around eight thousand years ago are not related to one another according to the tree model. Instead, his analysis showed that East Asians today are genetically more closely related on average to the ancestors of ancient European hunter-gatherers than they are to the ancestors of present Europeans. Ancient DNA studies prior to his work had already shown that present-day Europeans derive some of their ancestry from migrations of farmers from the Near East, who I had assumed were derived from the same ancestral population as European hunter-gatherers. Lazaridis now realized that the ancestry of the first European farmers was distinct from European hunter-gatherers in some way. Something more complicated was going on.
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Present-day Europeans and Near Easterners are mixed: they carry within them ancestry from a divergent Eurasian lineage that branched from Mal'ta, European hunter-gatherers, and East Asians before those three lineages separated from one another.
Lazaridis called this lineage "Basal Eurasian" to denote its position as the deepest split in the radiation of lineages contributing to non-Africans. The Basal Eurasians were a new ghost population, one as important as the Ancient North Eurasians, measured by the sheer number of descendant genomes they have left behind. The extent of the deviations of the Four Population Test away from the value of zero that would be expected if the populations were related by a simple tree indicates that this ghost population contributed about a quarter of the ancestry of present-day Europeans and Near Easterners. It also contributed comparable proportions of ancestry to Iranians and Indians.
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After around fourteen thousand years ago, a group of hunter-gatherers spread across Europe with ancestry quite different from that of the people associated with the preceding Magdalenian culture, whom they largely displaced. Individuals living in Europe between thirty-seven thousand and fourteen thousand years ago were all plausibly descended from a common ancestral population that separated earlier from the ancestors of lineages represented in the Near East today. But after around fourteen thousand years ago, western European hunter-gatherers became much more closely related to present-day Near Easterners. This proved that new migration occurred between the Near East and Europe around this time.
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The farmers in present-day Turkey expanded into Europe. [...] 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. This meant that the high genetic substructure that had previously characterized West Eurasia collapsed into the present-day very low level of genetic differentiation by the Bronze Age.
So Northern Europeans actually have a ton of the Middle Eastern ancestry that Nordicists have always looked down on. And while they still have some of their beloved European hunter-gatherer ancestry, it turns out that's Asian-related. Furthermore, large parts of their Middle Eastern and Asian/Amerindian-type ancestries arrived long after Paleolithic and Neolithic times in the Bronze Age.
Of course, the same goes for Southern Europeans, but they generally have more of the older Neolithic farmer ancestry and less of the exotic "Asiatic" ancestries. And the originators of European civilization — Minoan and Mycenaean Greeks, as well as Etruscans and Romans — were genetically like modern Southern Europeans, not like modern Northern Europeans as the Nordicists have always claimed.
So in a pissing contest of who's "more European", playing by Nordicists' own rules, Southern Europeans would have to be considered the "winners".
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David Reich. Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. Oxford: Oxford University Press, 2018.
