I’m quite looking forward to Steven Pinker’s The Better Angels of Our Nature: Why Violence Has Declined. It’s coming out in three weeks, so expect to hear a lot more about it. That violence has declined is known outside of Pinker’s own work, and I try and spread this “good news” as much as I can. But I’ve always found it peculiar that some of the most pessimistic and skeptical individuals in regards to these data aren’t reactionaries pining for the ancient idyll, but self-styled progressives who seem to believe that we are fallen creatures. Many of the latter are clearly modern followers of Rousseau, previously discussed in The Blank Slate.
To be tagged as a credulous optimist is one thing, yet Pinker also risks being condemned as a scientific racist. His graphs on the incidence of murder show present-day tribal and hunter-gatherer cultures to be far more homicidal than even the most lethally armed developed nation, a fact that is bound to bring censure from those Pinker derides as the “anthropologists of peace”
If the reviewer is characterizing these “anthropologists of peace” correctly perhaps it’s a commentary on what modern anthropology has become. I’ll leave you with some charts….
I have criticized the “pots not people” paradigm on this weblog before. In short, the idea is that material cultural changes reflected in the archaeological record are an indicator of memetic, not genetic, evolution. So a shift from pottery style X to pottery style Y informs you of an cultural switch. This is not implausible on the face of it. In the year 450 the dominant religion in the Roman Empire was a derived Jewish sect, Christianity. The only other de jure recognized religious organization within the Empire was another derived Jewish sect, an early form of Rabbinical Judaism.* But most people assume that there was far less genetic gains to Jews and Jewish-derived people. Rather, it was Jewish ideas which spread to non-Jews, and superseded non-Jewish ideas.
For most of my life I have had an implicit directional view of Holocene human culture. And that direction was toward more social complexity and cultural proteanism. Ancient Egypt traversed ~2,000 years between the Old Kingdom and the fall of the New Kingdom. But it s rather clear that the cultural distance which separated the Egypt of Ramesses and that of Khufu was smaller than the cultural distance which separates that of the Italy of Berlusconi and the Italy of Augustus. Not only is the pace of change more rapid, but the change seems to tend toward complexity and scale. For most of history most humans were primary producers (or consumers as hunter-gatherers). Today primary producers are only a proportion of the labor force (less than 2% in the USA), and there are whole specialized sectors of secondary producers, service workers, as well as professionals whose duty is to “intermediate” between other sectors and smooth the functioning of society. The machine is more complex than it was, and it has gotten more complex faster and faster.
This is a accurate model as far as it goes, but of late I have started to wonder if simply describing in the most summary terms the transition from point A to Z and omitting the jumps from B to C to … Y may hide a great of the “action” of human historical process. My post “The punctuated equilibrium of culture” was inspired by my deeper reflection about the somewhat staccato character of cultural evolution. Granting that the perception of discontinuity is a function the grain at which we examine a phenomenon, I think one can argue that to a great extent imagining the change of cultural forms as analogous to gradualistic evolution or the smooth descent of a ball toward the center of the earth is deceptive. The theories of history which many pre-modern peoples espoused can give us a window into perception of changes in the past: history was quite often conceived of as cyclical, rising and falling and rising. And yet even in the days of yore there were changes and increases in complexity. The Roman legions of Theodosius the Great in 390 A.D. were more complex institutions than those of Scipio Africanus in 200 B.C. The perception of stasis, and even decline, is due to the fact that the character and complexity of societies did not seem to exhibit direction over the short term toward progress. And that short term can be evaluated over centuries. Far longer than any plausible human lifetime. So while it is all well and fine to focus on the long term trend line, the details of how the trend emerged matter a great deal when attempting to construct a model of the past which can allow us to make robust and rich inferences. The people of the past made robust inferences over any scale of time which mattered to them. The world was nearly as likely to get less rich as more rich.
As many of you know when you have two adjacent demes, breeding populations, they often rapidly equilibrate in gene frequencies if they were originally distinct. There are plenty of good concrete examples of this. The Hui of China are Muslims who speak local Chinese dialects. The most probable root of this community goes back to the enormous population of Central Asia Muslims brought by the Mongol Yuan dynasty that ruled ruled China for over a century from the late 1200s to 1300s. Genetic studies of this group that I’ve seen indicate that a high bound estimate for West Eurasian ancestry is ~10%. The other ~90% is interchangeable with the Han Chinese. So let’s assume that the Hui are ~10% West Asian. If you assume that in the year 1400 the Hui were “pure,” you have 24 generations (25 years per generation). The original population of “Central Asian Muslims” were heterogeneous, including Iranians and Turks. But let’s take it granted that they were 50% East Eurasian and 50% West Eurasian in ancestry at the time of their arrival. What would the intermarriage rate per generation have to be so that the Hui are ~10% West Eurasian at t = 24 (24 generations after the beginning of intermarriage assuming 50/50 West vs. East Eurasian splits)? Turns out all you need is a constant 7% intermarriage rate per generation (the Han Chinese population is so large in relation to the Hui that you can model it as infinite in size).
The situation gets even simpler when you have one population which divides into two. For example, imagine that the Serbs and Croats fissioned from a set of unstructured South Slavic tribes which filtered into ancient Illyria ~600 A.D. Soon enough there was a cultural division between the two in terms of religion (Western vs. Eastern Christian) which threw up a population genetic barrier. If you assume that genetically the two groups were totally similar at t = 0, and you separated them perfectly, over time they would diverge due to drift in their allele frequencies. But the reality is that barriers between geographically close groups do not prevent all intermarriage. Even extremely insular groups in a cultural sense such as the Roma of Eastern Europe are clearly heavily admixed with their surrounding populations, as they seem to be no more than ~50% South Asian in total genome content. Going back to the South Slavs, who start out very similar in our putative scenario, how much intermarriage will be necessary for them to not diverge? The issue is not the rate of intermarriage, rather, one migrant per generation across the two demes will be sufficient to equilibrate allele frequencies. On the face of it this seems implausible, but recall that divergence is driven mostly by drifting of genes as well as new variation (whether through other exogenous migratory sources or mutation). Very small populations are subject to a lot of drift, and so diverge rapidly, but only very few migrants are needed to bring it back into alignment, because they are proportionally significant. In contrast, the frequencies of large populations are less buffeted by generation-to-generation sample variance (e.g., 10 tosses of a coin will deviate more from 50/50 proportionally than 100 tosses), requiring less gene flow proportionally to maintain parity.
The image above is adapted from the 2010 paper A Predominantly Neolithic Origin for European Paternal Lineages, and it shows the frequencies of Y chromosomal haplogroup R1b1b2 across Europe. As you can see as you approach the Atlantic the frequency converges upon ~100%. Interestingly the fraction of R1b1b2 is highest among populations such as the Basque and the Welsh. This was taken by some researchers in the late 1990s and early 2000s as evidence that the Welsh adopted a Celtic language, prior to which they spoke a dialect distantly related to Basque. Additionally, the assumption was that the Basques were the ur-Europeans. Descendants of the Paleolithic populations of the continent both biologically and culturally, so that the peculiar aspects of the Basque language were attributed by some to its ancient Stone Age origins.
As indicated by the title the above paper overturned such assumptions, and rather implied that the origin of R1b1b2 haplogroup was in the Near East, and associated with the expansion of Middle Eastern farmers from the eastern Mediterranean toward western Europe ~10,000 years ago. Instead of the high frequency of R1b1b2 being a confident peg for the dominance of Paleolithic rootedness of contemporary Europeans, as well as the spread of farming mostly though cultural diffusion, now it had become a lynch pin for the case that Europe had seen one, and perhaps more than one, demographic revolutions over the past 10,000 years.
This is made very evident in the results from ancient DNA, which are hard to superimpose upon a simplistic model of a two way admixture between a Paleolithic substrate and a Neolithic overlay. Rather, it may be that there were multiple pulses into a European cul-de-sac since the rise of agriculture from different starting points. We need to be careful of overly broad pronouncements at this point, because as they say this is a “developing” area. But, I want to go back to the western European fringe for a moment.
In my long post below, Celts to Anglo-Saxons, in light of updated assumptions, I had a “cartoon” demographic model in mind which I attempted to sketch out in words. But sometimes prose isn’t the best in terms of precision, and almost always lacks in economy.
In particular I wanted to emphasize how genes and memes may transmit differently, and, the importance of the steps of going between A to Z in determining the shape of things in the end state. To illustrate more clearly what I have in mind I thought it might be useful to put up a post with my cartoon model in charts and figures.
First, you start out with a large “source” population and a smaller “target” population. Genetically only the migration from the source to the target really has an effect, because the source is so huge that migration from the target is irrelevant. So we’ll be focusing on the impact upon the target of migration both genetically and culturally.
To simplify the model we’ll imagine a character, whether genetic or memetic, where the source and target are absolutely different at t = 0, or generation 1. Also, these are discrete generations, and the population is fixed, so you can presume that it’s at carrying capacity. Migration of the outsiders into the target population from the source means less of the original native population in absolute terms (to be realistic this is bidirectional, so people are leaving the target too, but that’s not our concern here).
There are two time series which illustrate the divergent dynamics on both the genetic and memetic dimensions. In one series you see gradual and continuous migration from the source to the target population over 13 generations. In another there are two generations of massive migration, before and after which there is no migration. For the genetic character, imagine disjoint allele frequencies at generation 1. So at generation 1 the target population is at 100% for allele A, while the source is at 100% for allele B. Therefore migration of from the source to the target results in a decrease in the proportion of allele A, which is what is being measured on the y-axis. For the memetic character, imagine that it’s language. So at generation 1 100% in the target zone speak language A, while everyone in the source zone speak language B. Again, the frequency on the y-axis is of the proportion who speak language A in the target zone.
I recall years ago reading Spencer Wells discuss how important it was to sample “indigenous people”* before they were swallowed up by the cresting panmixia. Of course panmixia has to be conditioned on the fact that the vast majority of Han Chinese are stilling reproducing with other Han Chinese, and so forth. But it seems plausible to argue that the great agricultural Diasporas are only today swallowing up the residual of marginalized groups outside of the farming frontier. These populations which expanded from agricultural hearths over the Holocene may only be a shadow of the genetic variation which was once extant after the last Ice Age, as the thinly populated landscape was fractionated into endogamous networks as a matter of necessity rather than preference.
First, let’s recall that over the long term “effective population size” is defined by the harmonic mean. Concretely, a population of 1 billion can be far more genetically homogeneous than a population of 1,000, if, those 1 billion only recently expanded from far smaller populations. Imagine a toy example of two populations, A & B. They both begin in generation 1 with a population size of 1,000. In generation 3 both experience a population drop, A to 750, and B to 85. Now, assume that A bounces back to 1000 and maintains that population for the next 20+ generations. In contrast, B begins to double in population size each generation. Here’s a log-transformed chart illustrating the different population sizes:
Randy McDonald just pointed me to a 2008 paper in AJHG, Japanese Population Structure, Based on SNP Genotypes from 7003 Individuals Compared to Other Ethnic Groups: Effects on Population-Based Association Studies. It speaks to an issue I brought up earlier in my post, Sons of the farmers, the story of Japan, which describes the ethnogenesis of the Japanese modern people from the Yayoi culture. The Yayoi presumably brought rice from the Asian mainland, probably from what is today southern Korea. But the Japanese islands were not uninhabited before this period. Japan was home to the Jomon culture, which has a rather storied history in the annals of archaeology. The Jomon seem to have been a predominantly hunter-gatherer population which was also sedentary, and engaged in the production of objects such as pottery which are normally associated with more advanced farming societies. I have a difficult time crediting the ~13,000 year period of continuous development which is attributed to the Jomon, but, it does seem likely that the period between 2,000 and 2,500 years before the present did mark a sharp cultural discontinuity in the Japanese islands, as Jomon gave way to Yayoi.
A related issue to this indisputable cultural shift is the question of whether it was accompanied by a demographic transition. This particular debate is fraught with politics, but we have enough genetic information that we can hazard a tentative guess. It does look like the Jomon-Yayoi cultural shift was accompanied by a significant demographic transition. In particular, the Ainu of the north and the inhabitants of the Ryukyu islands in the south seem distinctive from the majority of Japanese who inhabit the core islands. The hypothesis that these peoples are more related to the Jomon, or directly descended from them. One must distinguish these two groups though; the Ainu remained culturally distinctive from the Japanese, in lifestyle and language before their de facto absorption into the Japanese of late. In contrast, the people of the Ryukyus today seem to be clearly related to the southern Japanese in both language and lifestyle. If the Ryukyu islanders preserve more of the Jomon ancestral heritage, it may simply be due to the dilution of the signal of the original Yayoi pioneers as they moved south.
But there is another piece of the puzzle which has always been a point of curiosity for me: what happened to the non-Japanese populations of northern Honshu? Termed Emishi, these people retained a distinctive identity in northern Honshu until ~1,000 years ago. Fragmentary references in the historical texts make it clear that these people did not speak Japanese natively, and were physically different in appearance, being a “hairy” and “bearded” people. This is how the Ainu were also described, and because of the Emishi’s geographical proximity to Hokkaido it is presumed there may have been a cultural continuity. It turns out that the 2008 paper hints at the genetic imprint of the Emishi.
Long time readers know well my fascination with quantitative history. In particular, cliometrics and cliodynamics. These are fields which attempt to measure and model human historical phenomena and processes. Cliometrics is a well established field, insofar as it is a subset of economic history. But cliodynamics is new on the scene. At the heart of cliodynamics is the quantitative ecologist Peter Turchin. I highly recommend his readable series of books, Historical Dynamics, War and Peace and War, and Secular Cycles. Also, see my reviews of the first two books.
With that, I am rather excited by the debut of Cliodynamics: The Journal of Theoretical and Mathematical History. Here’s the description of the brief of the field and the journal:
‘Cliodynamics’ is a transdisciplinary area of research integrating historical macrosociology, economic history/cliometrics, mathematical modeling of long-term social processes, and the construction and analysis of historical databases. Cliodynamics: The Journal of Theoretical and Mathematical History is an international peer-reviewed web-based/free-access journal that will publish original articles advancing the state of theoretical knowledge in this discipline. ‘Theory’ in the broadest sense includes general principles that explain the functioning and dynamics of historical societies and models, usually formulated as mathematical equations or computer algorithms. It also has empirical content that deals with discovering general empirical patterns, determining empirical adequacy of key assumptions made by models, and testing theoretical predictions with the data from actual historical societies. A mature, or ‘developed theory,’ thus, integrates models with data; the main goal of Cliodynamics is to facilitate progress towards such theory in history.
The first issue has an article by Sergey Gavrilets, David G. Anderson, and Peter Turchin. Gavrilets is a familiar face. I know him from his work in evolutionary theory. The paper itself is a readable and plausible model of how “medium scale” societies rise and fall through conflict and consolidation. Basically the stage of human society described in Laurence Keely’s seminal War Before Civilization; after agriculture, but before major literate state systems. Their basic method is to take a mathematical model with a tractable number of plausible parameters and run simulations which give one a sense of how it changes dependent variables of interest. Polities were modeled as being circumscribed hexagons; so they had six neighbors (instead of four which would be the case if they were squares). The area modeled had an “edge,” and polities can exist in a flat hierarchical structure, or eventually aggregate so they exhibit rank order. Additionally, polities varied by economic productivity. Finally, there was a temporal aspect in that there was a potential conflict per generation where the probability of success was conditional upon the strength of the polity. Being more powerful increase the probability of victory, but does not guarantee it. Flukes do happen. The full model can be found in the paper, which is open access. The math isn’t totally opaque, so I’m really not going to distill it down. You can swallow it whole. Rather, let’s look at the list of parameters and statistics:
A few days ago Robin Hanson brought this chart of world population to my attention:
On the x-axis you have time, 12,000 years ago to the present. On the y-axis an estimate of the total world population log-transformed. The data is derived from the US Census low estimate. Granting the data’s accuracy for the purposes of reflection, Robin’s question was what could have occurred between 1000 and 500 BC to produce such a rapid population rise?
It was famously reported last winter that Bushmen seem to differ genetically amongst themselves more than Europeans and Asians do. These two latter groups have been separate for at least 40,000 years.
At least? Razib, you are way off on the separation time of Europeans and East Asians. I think it’s much closer to 30,000 years at most. There is growing evidence that ancestral Europeans and ancestral East Asians were one and the same people until 22,500 years ago.
Present-day Europeans and East Asians descend largely from a small nomadic population that once roamed Eurasia’s northern tier—a belt of steppe-tundra that stretched from southwestern France to Beringia during the last ice age. This population then split in two around the time of the glacial maximum (Rogers, 1986; Crawford et al, 1997). Chronologically, this barrier to east-west gene flow matches the dating by Laval et al. (2010) of the split between ancestral Europeans and ancestral East Asians.
The italics are my words, emphasized by the commenter. The bolding is the commenter’s as well (I had to fix some HTML in that comment, but I think I corrected in line with the commenter’s intent). I read (and blogged) the paper cited, so I’m well aware of the low bound value implying more recent common ancestry of East and West Eurasians posited here. I’m moderately skeptical. Part of the issue is that these sorts of computational models are tricky, and most of us aren’t versed in the various moving parts which go into constructing the model. Consider the following from the cited paper:
I should mention I finished Why the West Rules a few days ago, and Tyler Cowen was spot on. The author is by training a classical archaeologist, and so the first portion of the book which focuses on archaeology, and up to the classical historical period, is thick, dense, and insightful. But as he pushes past the year 1000 A.D. it starts to become a mishmash of conventional wisdom and thinly explicated secondary sources. It began tight, but slowly unwound. There is no equivalent near the end of the book to the detailed exposition of the importance of the pre-literate Uruk Culture.
Here are some books which I’ve found more useful on the broad topic of economic and social history:
Uyghur boy from Kashgar
Every few years a story crops up about “European-looking” people in northwest China who claim to be of Roman origin. A “lost legion” so to speak. I’ll admit that I found the stories interesting, amusing, if implausible, years ago. But now it’s just getting ridiculous. This is almost like the “vanishing blonde” meme which always pops right back up. First, let’s quote from The Daily Mail,* DNA tests show Chinese villagers with green eyes could be descendants of lost Roman legion:
For years the residents of the remote north western Chinese village of Liqian have believed they were special.
Many of the villagers have Western characteristics including green eyes and blonde hair leading some experts to suggest that they may be the descendants of a lost Roman legion that settled in the area.
Now DNA testing of the villagers has shown that almost two thirds of them are of Caucasian origin.
The results lend weigh to the theory that the founding of Liqian may be linked to the legend of the missing army of Roman general Marcus Crassus.
In 53BC, after Crassus was defeated by the Parthians and beheaded near what is now Iran, stories persisted that 145 Romans were captured and wandered the region for years.
As part of their strategy Romans also hired troops wherever they had conquered and so many Roman legions were made up not of native Romans, but of conquered men from the local area who were then given training.
Let’s start from the end. The last paragraph indicates a total ignorance of the nature of military recruitment during the late Republic. In the year 110 BC the Roman army was composed of propertied peasants. These were men of moderate means, but means nonetheless. They fought for the Republic because it was their duty as citizens. They were the Republic. Due to a series of catastrophes the Roman army had to institute the Marian reforms in 107 BC. Men with no means, and who had to be supplied with arms by the Republic, joined the military. This was the first step toward the professionalization of the Roman legions, which naturally resulted in a greater loyalty of these men to their leaders and their unit than the Republic. Without the Marian reforms Sulla may never have marched on Rome. By 400 AD the legions were predominantly German in origin, and supplemented with “federates,” who were barbarian allies (though alliances were always subject to change). But in 53 BC this had not happened yet. The legions who marched with Crassus would have been Roman, with newly citizen Italian allies in the wake of the Social War. The legions of the Julio-Claudians were probably still mostly Italian, a century after Crassus (service in the legions, as opposed to the auxiliaries, was limited to citizens, who were concentrated among Italians). So that objection does not hold.
I am about two-thirds of the way through Why the West Rules-for Now: The Patterns of History, and What They Reveal About the Future, and I have to agree with Tyler Cowen’s assessment so far. The author is an archaeologist, and though a little less shy in regards to general theory than most in his profession, he still seems to exhibit the tendency to focus on thick-detail without any elegant theoretical scaffolding. In some ways it is an inversion of Gregory Clark’s A Farewell to Alms: A Brief Economic History of the World, which manifests an economist’s preference for stylized system-building at the expense of the messy residual. Why the West Rules has added almost no broad-brush theoretical returns beyond what you could find in Guns, Germs and Steel and The Wealth and Poverty of Nations. Though the author has a lot of scrupulously footnoted detail which probably makes Why the West Rules a worthy read.
Dienekes Pontikos ruminates on the changes in human genetic variation on a world-wide scale over the past 10,000 years based on an MDS plot of East Eurasian genetic variation which he generated. I’ve taken his plot and added geographical labels, so you can see the difference in scale between geography and genetics in terms of distance:
Dienekes Pontikos keeps chugging along, and has cranked out a new bar plot from the ADMIXTURE program with 15 putative ancestral components. He has “69 populations, and 1,189 individuals in total.” Most of these were assembled from public data, but some of them are particular to the Dodecad Ancestry Project. He contends:
In comparison to the K=10 analysis, the increased resolution allows us to:
- South Asians belonged primarily to the South Asian and West Asian components; this South Asian component spilt over to Iran and Central Asia. Now, a new Central-South Asian component, corresponding to the Ancestral North Indian of a recent study is inferred, and a corresponding South Indian component.
- HGDP Bedouins and Behar et al. (2010) Saudis take up their own component which I labeled Arabian. This appears to be a subset of the Southwest Asian component of the K=10 analysis
- There are several components in Siberian and Central Asian populations, alread discovered in my regional analysis. These are Central Siberian, Nganasan, Koryak, Chukchi, and Altaic which replace the K=10 Northeast Asian component
Not only has he generated a bar plot, but there is a PCA showing the relationship between the 15 ancestral groups, as well as a hierarchical tree. Since he references to the ANI and ASI of Reich et al., I thought I would note that the South Indian element from Dienekes’ K = 15 is still found in appreciable portions in the Turkic groups which earlier exhibited the South Asian component. And, on the PCA and phylogenetic tree it still clusters with West Eurasians more than East Eurasians, which is not the case with ASI (or the various Indian mtDNA lineages which coalesce back to a more recent common ancestor with East Eurasians).
The bar plot is below. Of interest are the most “pure” European groups, the Sardinians and Lithuanians. Also, compare Scandinavians and Finns.
Ruchira Paul has her own reaction to Zadie Smith’s pretentious review of The Social Network. One of the aspects of Smith’s review which Ruchira focuses upon is her concern about the extinction of the “private person.” I have mooted this issue before, but I think it might be worthwhile to resurrect an old hobby-horse of mine: is privacy as we understand it in the “modern age” simply a function of the transient gap between information technology and mass society? In other words, for most of human history we lived in small bands or in modest villages. These were worlds where everyone was in everyone else’s business. There was very little privacy because the information technology was well suited to the scale of such societies. That “technology” being our own innate psychology and verbal capacities. With the rise of stratified cultures elites could withdraw into their own castles, manses and courtyards, veiled away from the unwashed masses. A shift toward urbanization, and greater anonymity made possible by the rise of the mega-city within the last few centuries, has allowed the common citizen to also become more of a stranger to their neighbors. It is far easier to shed “baggage” by simply moving to a place where everyone doesn’t know your name.
When it comes to the synthesis of genetics and history we live an age of no definitive answers. L. L. Cavalli-Sforza’s Great Human Diasporas would come in for a major rewrite at this point. One of the areas which has been roiled the most within the past ten years has been the origin and propagation of the agricultural lifestyle across the European continent between 10,000-6,000 years before the present (starting in Europe’s southeast fringe a few thousand years after the origination of the Neolithic lifestyle in the Levant, and finally pushing into the southern Scandinavian peninsula only ~6,000 years ago). The reasons for this particular debate about the origin of the European are manifold. First, most scholars are of European ancestry, and some of the debates have roots going back a century. So a natural interest exists based on normal human biases. Second, when it comes to genetics the climate of Europe is ideal for the preservation and extraction of ancient DNA. Third, there are relatively clear and distinct theoretical models which can be tested by the data, whether to verify or refute.
I have already reviewed earlier work in three previous posts, European man perhaps a Middle Eastern farmer, European man perhaps not a Middle Eastern farmer, and Völkerwanderung back with a vengeance. Instead of rehashing everything I’ll take it as a given that you’ve read or skimmed those posts. Rather, let’s move on to a new paper in PLoS Biology, Ancient DNA from European Early Neolithic Farmers Reveals Their Near Eastern Affinities:
The figure to the left is a composite merged from two different papers. One analyzes the patterns of genetic variation within African Americans, and the other the patterns within the East Turkic ethnic group, the Uyghurs. The bar plots show the ancestral element which is similar to two parent populations which resemble Europeans and Africans or East Asians. Looking at total aggregate ancestral quanta we infer that African Americans are on the order of 15-25% European in ancestry, and 75-85% African. Uyghurs seem to be a composite in even measure of a European-like group, and an East Asian-like group. This makes total sense phenotypically; most African Americans look more African, while Uyghurs seem to exhibit a phenotype on average which spans the middle-range between West and East Eurasians.
But we’re clearly missing something when we focus purely on a population level statistic. Each “slice” of the bar plot actually represents an individual. Note the contrast between African Americans and Uyghurs. There is relatively little intra-individual variation among Uyghurs, while there is a great deal of such variation among African Americans. Why? Population geneticists have looked at linkage disequilibrium in both African Americans and Uyghurs, and inferred that the former went through an admixture phase much more recently than the latter. Though you don’t really have to be a population geneticist to have known that about African Americans. The ethnogenesis of the group African Americans as a cultural entity occurred in the period between 1650 and 1850. Genetically they are a compound of African, European, to some extent Native American, ancestry. For the Uyghurs we have thinner textual evidence, but the visual and genetic data point to a “western” Indo-European speaking population in the Tarim basin before the arrival of the Turks sometime in the second half of the first millenium A.D. The assumption is that after the initial admixture event and the absorption of the pre-Turkic substrate there was no population substructure. Over time the two components distributed themselves evenly across the population over a period of 1,000-1,500 years.
From this we can infer that patterns of individual variation within populations, as well as between closely related populations, can tell us a great deal. Today the Dodecad Ancestry Project posted a file with the population ancestries broken down by individuals. Looking at this sort of fine-grained data patterns can jump out based on what you already know. Below is a slide show I created which highlights some patterns of interest.
Recently there’s been some talk about how the Mercator projection distorts our perceptions of the world, in particular how it makes Africa seem very small in relation to North America, and about the same size as Greenland. But there’s another artifact of the Mercator projection as well: it misleads us in terms of our perception of how expansive and dispersed the Circumpolar region is. And it also allows for more surprise than should be the case in terms of the demographic and cultural exchanges which have occurred between the western and eastern antipodes of Eurasia.
Earlier this week I posited that there were broad similarities of culture and populations along the northern fringe of Eurasia which arose in the retreat of the ice sheets after the Ice Age. Those similarities were subsumed in some regions by the expansion of peoples practicing agriculture who pushed from the south. In the case of Russia the expansion of ethnic Russians east was a historically attested case of this. With modern transportation and comparative advantage coming to the fore Siberian Russians were less dependent on primary production in the local hinterlands around their settlements, so the ecological constraints which had preserved the northern peoples Siberia were to some extent removed.
Dienekes Pontikos has been doing some great work on collecting and analyzing genetic data from groups which academia has generally not focused on too much. Today he has posted an analysis of various Siberian groups, along with some Northern Europeans and East Asians. Below are the two primary visualizations, and MDS which illustrates genetic variance on a two-dimensional plot, and an ADMIXTURE derived bar plot which has ancestral quota for the total population sets.