Skull of Cheddar Man (Wikicommons)
The first modern Britons, who lived about 10,000 years ago, had "dark to black" skin, a groundbreaking DNA analysis of Britain's oldest complete skeleton has revealed.
The fossil, known as Cheddar Man, was unearthed more than a century ago in Gough's Cave in Somerset. [...] It was initially assumed that Cheddar Man had pale skin and fair hair, but his DNA paints a different picture, strongly suggesting he had blue eyes, a very dark brown to black complexion and dark curly hair.
The discovery shows that the genes for lighter skin became widespread in European populations far later than originally thought. (Devlin 2018)
An ancient DNA study has made a big splash in the news. Its authors took the unusual step of releasing their findings to the media before presenting them at a scientific conference or in an academic journal. Not until more than a week later did they provide a paper describing their methods and their results. This paper was made available on BioRxiv, a preprint online repository, and it has yet to be accepted by a peer-reviewed journal.
Not surprisingly, these findings have been discussed in an atmosphere of Gotcha! journalism and trite moralizing. One of the authors, Yoan Diekmann, opined in an interview that the connection between Britishness and whiteness is "not an immutable truth. It has always changed and will change" (Devlin 2018).
Well, obviously. If I could travel back in time, I would encounter people who look less and less like me the farther back I go, and this would be true for any people anywhere in the world. We think of the Amerindians as being native to the Americas, yet their ancestors had earlier replaced a people with very dark skin and frizzy hair, similar in appearance to the natives of Papua New Guinea (Frost 2018). In Europe, the first modern humans to arrive some 45,000 years ago would have looked very African—not only in their skin color but also in their hair form, face shape, and body proportions.
This is what evolution is about, perhaps more so with our species. Human evolution is like a logarithmic curve. More genetic change has happened over the past 10,000 years than over the previous 100,000. And more has happened during those 100,000 years than over the previous one million. Our species is unique in having to adapt not only to a slowly changing natural environment but also to a faster-changing and increasingly diverse range of cultural and social environments (Hawks et al. 2007).
Another point: the Cheddar Man finding wasn't unexpected. We've already examined the DNA of two other Mesolithic humans, one from Loschbour in Luxembourg, dated to 8,000 years ago, and the other from La Braña in Spain, dated to 7,000 years ago. Both show the same combination of dark skin and blue/green eyes (Lazaridis et al. 2013; Olalde et al. 2014). How dark is 'dark'? They would have been much darker than a normal native European. The alleles in question are now so rare in native Europeans that anyone with them today most likely has a recent African ancestor.
Yes, this study has been criticized for inferring skin color from alleles at 16 genes. Although this number is adequate for European and Asian individuals, it isn't for Africans—among whom skin color is determined by alleles at many more genes (Barras 2018). This is the case with most genetically influenced traits: Europeans and Asians have much less genomic variability than do Africans because their ancestors left Africa as small 'founder' groups that took with them only a fraction of the original variability. But Cheddar Man, despite his skin color, was European; he was descended from humans who went through the Out-of-Africa bottleneck. Therefore, the study's methodology should work.
So Western Europe was once home to hunter-gatherers who, other than their blue eyes, were still largely African in appearance. Again, this is to be expected. If we go far enough back in time, we come to ancestors who didn't look like us. Perhaps less expectedly, we don't have to go very far back. The dark-skinned Mesolithic individual from Spain lived some 7,000 years ago, and there is no reason to believe he was the last of his kind. Indeed, dark skin seems to have persisted into the early Neolithic in some parts of Western Europe, like a Neolithic individual from England nicknamed 'Sven' and dated to 4,000-5,000 BP: "Sven most likely had intermediate to dark skin pigmentation, brown eyes and black possibly dark brown hair" (Brace et al. 2018). That last date puts us within the realm of recorded history—almost the time of Hammurabi.
All of this is consistent with earlier findings. Palaeontologists Marcellin Boule and Henri V. Vallois noted the African-like appearance of many Neolithic remains from Western Europe:
'In Brittany, as well as in Switzerland and in the north of Italy, there lived in the Polished Stone period, in the Bronze Age and during the early Iron Age, a certain number of individuals who differed in certain characters from their contemporaries', in particular in the dolichocephalic character of their skull, in possessing a prognathism that was sometimes extreme, and a large grooved nose. This is a matter of partial atavism which in certain cases, as in the Neolithic Breton skull from Conguel, may attain to complete atavism. Two Neolithic individuals from Chamblandes in Switzerland are Negroid not only as regards their skulls but also in the proportions of their limbs. Several Ligurian and Lombard tombs of the Metal Ages have also yielded evidences of a Negroid element.
Since the publication of Verneau's memoir, discoveries of other Negroid skeletons in Neolithic levels in Illyria and the Balkans have been announced. The prehistoric statues, dating from the Copper Age, from Sultan Selo in Bulgaria are also thought to portray Negroids. In 1928 René Bailly found in one of the caverns of Moniat, near Dinant in Belgium, a human skeleton of whose age it is difficult to be certain, but which seems definitely prehistoric. It is remarkable for its Negroid characters, which give it a resemblance to the skeletons from both Grimaldi and Asselar.
It is not only in prehistoric times that the Grimaldi race seems to have made its influence felt. Verneau has been able to see, now in modern skulls and now in living subjects, in the Italian areas of Piedmont, Lombardy, Emilia, Tuscany, and the Rhone Valley, numerous characters of the old fossil race (Boule & Vallois 1957: 291-292).
So the Western European hunter-gatherers didn't die out completely. They represent about 25% of the ancestry of Neolithic British individuals and about 10% of the ancestry of present-day white British (Brace et al. 2018). Nonetheless, they were largely replaced by people from elsewhere, perhaps beginning in the late Mesolithic—as suggested by the more intermediate skin color of the Loschbour individual (Brace et al. 2018).
How, then, did Western Europeans become white? When ancient DNA was first being retrieved, the answer seemed simple: the last hunter-gatherers in Western Europe were dark-skinned and the first farmers in Central Europe were light-skinned. Therefore, the modern European phenotype must have been brought to Europe by those farmers, who had apparently come from Anatolia (present-day Turkey).
This picture changed with retrieval of ancient DNA from hunter-gatherer sites in northeastern Europe, specifically Motala in Sweden (8,000 BP), Karelia in Russia (7500-7000 BP), and Samara in Russia (7,500-7000 BP). Those individuals had a fully modern European phenotype: pale skin with diverse hair colors (red, blond, black) and diverse eye colors (blue, brown) (Anthrogenica 2015; Eupedia 2015; Frost 2014; Frost et al. 2017; Mathieson et al. 2018). The modern European phenotype must have emerged even earlier, most likely during the last ice age of the Upper Paleolithic within an area stretching from the Baltic to mid-Siberia. To date, the earliest known individual with the derived allele for blond hair is from Afontova Gora (c. 18,000 BP) (Mathieson et al. 2018).
But what about the Neolithic farmers? How did they get to be white-skinned? Most likely through introgression. As they advanced into Europe, they intermixed with the native population.
Agriculture in a region may have been introduced by immigrants, but that does not mean that the immigrants carried mainly Near Eastern genes (Richards 2003; Rowley-Conwy 2004b; Zvelebil 2005). The LBK, for example, originated in the Carpathian Basin; the population that moved westward emerged there carrying a complex mix of European and Near Eastern mtDNA and no doubt picking up more as it moved. (Rowley-Conwy 2011: S434)
In some cases, farming communities took in hunter-gatherer individuals, especially women. In other cases, replacement was followed by reverse replacement, as with Neolithic culture in northwestern France: "After a couple of centuries it disappeared, replaced by a more widespread local Neolithic. Agriculturalized foragers appear to have absorbed the immigrants" (Rowley-Conwy 2011: S439).
In Western Europe, hunter-gatherers made a smaller contribution to the Neolithic gene pool (~25%) because of their low population density. The situation was like that of European settlers and native Amerindians in North America. Introgression was greater during the long time (7500-6000 BP) when the advance of Neolithic farmers stalled along a line stretching from the Low Countries in the West to the Black Sea in the East. To the north, along the shores of the Baltic and the North Sea, were hunter-fisher-gatherers with a relatively high population density (Frost 2017; Price 1991).
So to what degree are Europeans today descended from native Mesolithic hunter-gatherers and to what degree are they descended from Neolithic farmers of Anatolian origin? This question still has no reliable answer. On the basis of mtDNA, Skoglund et al. (2012) estimated Anatolian admixture at 95% in Sardinians, 52% in northwest Europeans, 31-41% in Swedes, and 11% in Russians. This methodology has a major flaw, however: if a group is a mixture of two other groups, its allele frequencies are assumed to be determined solely by the degree of intermixture. No allowance is made for differences in natural selection.
If we compare late hunter-gatherers with present-day Europeans, we see that the main change to mtDNA has been the loss of haplogroup U. Today, this haplogroup reaches high levels only among the Saami of Finland and the Mansi of northwestern Siberia, both of whom were hunter-gatherers until recently (Derbeneva et al 2002). Does the hunting-gathering lifestyle somehow favor this haplogroup? Balloux et al. (2009) argued that trade-offs between thermogenesis and ATP synthesis favor some haplogroups over others. In particular, haplogroup U is associated with reduced sperm motility—an indication that the energy balance is shifted from producing ATP to producing heat. Being nomadic, hunter-gatherers spend more time in the cold, especially when sleeping in temporary shelters. In contrast, farming makes possible a more sedentary lifestyle, including a warmer sleeping environment, and would therefore select against genetic variants, like haplogroup U, that increase body temperature at the expense of ATP production.
This hypothesis is testable. If haplogroup U disappeared because Anatolian farmers partially replaced native hunter-gatherers, this genetic change should coincide with the time boundary between late hunter-gatherers and early farmers. If this haplogroup disappeared through natural selection, the change should have occurred gradually over a longer period. The second scenario seems closer to the truth. In a study of 92 Danish human remains from the Mesolithic to the Middle Ages, Melchior et al. (2010) found that high incidences of haplogroup U persisted long after the advent of farming and apparently as late as the Early Iron Age.
Haplogroup U was likewise found to persist across the Mesolithic/Neolithic boundary when Jones et al. (2011) compared ancient DNA from Latvia and Ukraine. They also used nuclear DNA to compare the Mesolithic and Neolithic samples, as opposed to the mtDNA methodology of Skoglund et al. (2012). This time there was no evidence of Anatolian admixture in any of the Neolithic samples.
This is not to say that Anatolian farmers didn’t contribute to the European gene pool. They did, but researchers have overestimated this contribution by attributing all of the genetic differences between farmers and hunter-gatherers to population replacement. This is particularly the case with haplogroup U—the mtDNA marker that most sharply distinguishes farmers from hunter-gatherers. If mtDNA shows that Russians are 11% Anatolian, while nuclear DNA shows that Ukrainians are 0% Anatolian, the discrepancy is probably due to differences in methodology rather than a real difference between Russians and Ukrainians.
Conclusion
With the end of the last ice age, Europe had three major populations:
Western Hunter-Gatherers - attested from sites in Spain, Luxembourg, and England
- African appearance except for blue eyes (dark skin, dark curly hair)
Anatolian Farmers - attested from sites in central and southern Europe
- Spread into Europe from the southeast and intermixed with native hunter-gatherers as they advanced northward
- White skin, dark hair, dark eyes
Eastern Hunter-Gatherers - attested from sites in Sweden and Russia
- Fully modern European phenotype: white skin with a diverse palette of hair and eye colors
- By the late Mesolithic, high population densities along the Baltic and the North Sea
The Western Hunter-Gatherers went extinct after 7,000 BP, being replaced by Anatolian Farmers who by then had become heavily intermixed with native hunter-gatherers. After a relatively rapid expansion into southern, central, and western Europe, their wave of advance came to a halt around 7500 BP along a line stretching from the Low Countries to the Black Sea.
Meanwhile, Eastern Hunter-Gatherers along the Baltic and the North Sea had increased their numbers by exploiting marine resources (fish, shellfish, seals). As fisher-hunters they were able to create semi-sedentary societies with relatively large populations and high social complexity, thus forming a demographic barrier to the advance of farming until around 6,000 BP. They then adopted farming through cultural diffusion rather than population replacement. As farmer-fishers, they now expanded westward and southward, an expansion that continued into the historical period.
In this prehistoric drama, we like to see Mesolithic hunter-gatherers as beautiful losers who were steamrolled out of existence by savvier and more numerous farming peoples. This was true for the Western Hunter-Gatherers. There was another Mesolithic population, however: the hunter-fisher-gatherers along the shores of the Baltic and the North Sea. They achieved levels of population density and social complexity not only on a par with Neolithic societies but also rich in possibilities for future advancement. Of the three major populations in prehistoric Europe, they were the ones who would ultimately have the greatest demographic impact and lead the way to behavioral modernity, i.e., individualism, reduced emphasis on kinship, and the market as the main organizing principle of social and economic life. They not only survived but also went on to create what we call the Western World. Not bad for a bunch of losers.
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