The figure to the left is from Paleolithic DNA from the Caucasus reveals core of West Eurasian ancestry. It is a graph which captures general features of human population historical relationships as we understand them today. Or at least the model fits the data (remember, many models may fit the data!). The graph is complex…but even within the text of the preprint, the author admits that it is characterized by simplifying assumptions, which nevertheless are informative of some general dynamics and processes (e.g., pulse admixtures).
To some extent, the whole last generation or so has been characterized by the victory of a simplifying assumption that captures general truths about the past, with the accumulation of modifications on the margins as more nuanced results enter the picture. The simplifying assumption I am talking about here is the “out of Africa” 50,000 years ago with a total replacement of all other human lineages framework.
By the last quarter of the 20th century, a combination of archaeological and genetic evidence pointed to the likelihood of a massive bottleneck and expansion of humans outside of Africa in the relatively recent past. In the pre-genomic era, the tools were coarse, from uniparental lineages, classical markers, microsatellites, morphometric analyses, as well as archaeological surveys. But, they strongly pointed to massive expansion and population turnover ~50,000 years ago. This, combined with a line of thinking which suggested that Neanderthals were “evolutionary dead-ends” led to the thesis that there was a total replacement.
To a great extent, this model seems to hold up in the broad sketch. But not to an absolute and total degree. Some paleoanthropologists and geneticists were pointing out for decades that the tools we had could not exclude the possibility of admixture at lower fractions with earlier lineages in Eurasia on purely statistical grounds. These scholars were correct, as it turns out. There is now high confidence that in the range of 1-5% of the ancestry of non-Africans derives from highly diverged “archaic” lineages, Neanderthals and Denisovans. The fraction is low enough that more coarse methods did not definitively pick them up, and without ancient genomes, the “game of inference” was not dispositive in either direction. This, despite the fact that these Eurasian hominins’ ancestors seem to have diverged from those of modern humans ~750,000 years ago. Ultimately, scientists needed a physical ancient genome which they could compare to modern populations to come to this conclusion (before the Denisovan result, scientists had been noticing anomalies in Oceanian data for a decade or so but generally ignored it as beneath comment…a presentation was given an anthropology conference on archaic admixture in Oceania right before the Denisova cave paper).
The second major issue is that the massive expansion and bottleneck that occurred ~50,000 years ago may not explain all of the remaining ancestry that is not “archaic.” That is, there were many modern human lineages present 50,000 years ago. The major lacunae in the current model is a huge one: populations within Sub-Saharan Africa maintained larger population sizes throughout this event. And, anatomically modern humans predate this expansion by hundreds of thousands of years. From an archaeological perspective, a lower limit is 200,000 years ago, and an upper limit probably exceeds 300,000 years ago. Additionally, there are “deep lineages” within Africa which clearly predate the expansion 50,000 years ago. There is a strong consensus that the Khoisan people have at least some substantial ancestry that diverged more than 150,000 years ago from other humans, and tentative suggestions from several different research groups suggest that there are even more “basal” (deep divergence) lineages in parts of West Africa that the component within the Khoisan.
This does not even address the likelihood that some “archaic” ancestry persists within Sub-Saharan Africa just as it does outside of Sub-Saharan Africa.
She wants to go to college to study architecture. She would like to take English classes. She is wondering about how to harness her newfound media stardom.
In Saudi Arabia, Ms. Alqunun was a first-year university student, studying basic science and math. One of 10 children of a well-off emir, she said that life had been financially comfortable, but that she had no freedom.
Things grew even harder, she said, when her father left the city and put her under the guardianship of her older brother. She described her life as one of strict rules and abuse at the hands of her family. After she cut her hair in a way her family did not approve, her brother locked her in a room for six months, she said. A few months ago, when she removed her niqab, he beat her and locked her up again, she said.
Rahaf Mohammed Alqunun is like many people who read this weblog. The “life of the mind” is important to us, the freedom to learn, to experience. To make use of one’s liberty to flourish.
When reading the biography of an early fighter for the liberties of American women, Elizabeth Cady Stanton, Iperceive a clear distillation of myself, despite differences of race, sex, and time. The genius, the power, of the early Enlightenment movement and the universalisms that it unleashed is that is that it refracts our common individual yearnings, and propagates them throughout humanity. To me, this is the culmination of the visions of the “Good Society” propagated by the religions and ethical systems of the Axial Age thousands of years ago: “There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus.” I may not believe in the Christ Jesus, but I believe in common humanity.
This is not to say that I am here promoting a flat, formless society, defined by our most pressing near impulses. Human societies tend to exhibit order, hierarchy, and tradition. Men and women are different from each other, just as people of different religions and social classes tend to have different values and habits. We are not all the same, but there are common threads which bind us together in our humanity.
The society of the Kingdom of Saudi Arabia is one where women, half the population, are chattel to men with power, whether it be their father or their brother. Their “guardians,” who tend them like they are valuable sheep. The fundamental problem with the society of KSA is that it is not in balance, with its surfeit of petro-profits perpetuating a system of sex-slavery that most of the world has long moved beyond.
Today we have moved to a global consensus that holding other human beings as property without the rights of humanity on account of their origin or life circumstance is wrong. That such deprivation of liberty is without justice. Our brothers’ blood cries out from the lashes received. As this century progresses I believe we will see that the same is true of women in the KSA.
Salon is stiffing freelancers of $150. I think this is more a commentary on the market for freelancers than Salon‘s always tenuous finances. The market-clearing price for a lot of web journalism/commentary is pretty low. Salon does this because it knows freelancers will tolerate and accept this behavior more often than not.
This long article from Huffington Post (and boosted on the editor in chief’s Twitter), Everything You Know About Obesity Is Wrong, is being widely shared on Facebook (I haven’t seen it much on my Twitter, but that’s because I follow mostly scientists).
Of course it’s really really light on the science of nutrition. Or should I say “science”? Because the truth is that nutrition science has a lot of problems, so there is space to criticize it. But that being said, this piece is being shared by people who seem to think that there is a conspiracy make it seem like being obese is unhealthy. But most of the article is about how cruel people are to the obese, especially medical professionals. There’s really little evidence presented that being obese doesn’t cause issues with morbidity and mortality. Quotes like this are representative: “But individuals are not averages: Studies have found that anywhere from one-third to three-quarters of people classified as obese are metabolically healthy.” That’s a huge interval. Why?
Ultimately the article should have been titled Everyone Is Cruel to Obese People and That is Wrong and Ineffective.
I bought Early China: A Social and Cultural History. A lot of archaeology. But that’s what you get! I figure I should know more about Zhou China though. I think next I’ll try to read up on Neo-Confucianism, a topic I’ve been lax in because of my leaning toward “Han learning.”
Highly recommend Viet Nam: A History from Earliest Times to the Present. Most of the book does not deal with the Vietnam War. One curious thing I learned: the Vietnamese identity in the period around 0 AD was strong influenced by the influx of Yue people from southern China, as they imparted their culture and statecraft on the proto-Vietic populace. Of course on top of that came later Chinese migration, which resulted in the emergence of Vietnamese as a tonal language.
Though you’ll probably really want Phở as you read the book….
Also, I knew this, but Viet Nam makes it clear in all the gory details that the Austronesian Cham people of central and southern coastal Vietnam were undergoing the same shift to Islam from Hinduism that was occurring further south in the period after 1500. It seems rather clear that the emergence of a Cham sultanate on the model of Mataram or Johor never occurred because the Vietnamese conquered the Cham kingdom, and then assimilated or exterminated most of the natives. Many Cham fled to Cambodia, where they form the Muslim minority of that nation.
But, a small minority of Cham remain in Vietnam, and amongst these are a substantial Saivite Hindu community. It seems entirely possible that if the Cham had retained their independence as a nationality one would have seen total Islamicization, as occurred among the Malays. As is this, this process was retarded by Vietnamese conquest, and so some Chams still remain Hindu (the same process applies to the Philippines, where the native population was influenced by Hinduism first, and was in the first stages of Islamicization, when the Spaniards conquered the archipelago).
This AJ+ video about “white feminism” is getting a lot of attention. Mostly because AJ+ is backed and owned by a conservative Salafist regime which runs an oligarchic state on the backs of dark-skinned South Asian indentured labor. I’ve spent a week in Qatar at a really nice hotel. I’ve never encountered service staff as solicitous and courteous in the United States. At some point I may write about how certain organizations and institutions use political movements as instruments…but I always feel this is so obvious.
Next week on The Insight we’ll be talking about Indian genetics, again. Partly in anticipation of the ancient DNA paper, which should drop any day now (I have no inside information). Question suggestions welcome.
The Austronesian expansion actually makes me consider the possibility that we may never understand why the modern humans in the Near East ~55,000 years ago “broke out” and absorbed all the other hominin groups.
There are lots of things from Imperial China 900–1800 that I learned, though more often it simply deepened my knowledge. At this point, I am curious about something that is more like economic history (yes, I’ve read The Great Divergence). Recommendations?
Here is a fact I learned from Imperial China 900–1800 that might be of interest: in the late 17th century the expanding Manchu Empire (which had conquered China) and Russia began to jostle for power in Inner Asia, and the Khalkha Mongols, the Mongols proper, were deciding which side to align with. I had long known that the Khalkha Mongols had aligned with the Manchus. What became the Manchu imperial line had a genealogical relationship with the Mongols, as they would often take wives from a particular group of Mongol tribes (Kangxi Emperor’s paternal grandmother was a Mongol). Imperial China makes it clear that Mongol cavalry units were critical elements of the Manchu military machine, and as the Manchu assimilated into the Han culture they became arguably even more important as a population which could provide militarily ready men at a moment’s notice.
But a more interesting aspect of the Manchu alliance with the Mongols are the ethnoreligious implications, and what they wrought across Inner Asia. The Khalkha had become Tibetan Buddhists by the time the Manchus conquered China. According to Imperial China, their religious leaders argued for the furtherance of their alliance as junior partners to the Manchus as opposed to the expanding Russians in part because the Manchus were more respectful of Buddhism. Mind you, the Manchus were not themselves Tibetan Buddhists, though they were always keen to co-opt the various prominent Tibetan lamas. But, they had earlier practiced Chinese and Korean forms of Buddhism (as the Jurchens) and seemed resistant to Tibetan Buddhism in comparison to the Mongols.
The Russian Empire was obviously dominated by an Eastern Orthodox Christian elite. But, eventually, they made accommodations with various minority religions, including Buddhism. But, Buddhism, Islam, Judaism, and non-Orthodox Christianity were all subordinate religions. Historically non-Orthodox ethnic groups invariably suffered erosion due to the social advancement which conversion to Orthodoxy entailed. From the viewpoint of meta-ethnic identity, the Manchus were clearly superior to the Russians, as the Manchus tended toward more neutrality in religion than the Russians.
And yet there are two conditions that need to be highlighted here. The Manchus were responsible for the ethnic cleansing of the Mongol Dzungar tribes in the 18th century. The Dzungars were the last great Inner Asian polity to challenge the gunpowder empires. They were arguably the final flowering of the steppe and its way of war. Unlike the Khalkha Mongols the Dzungar tribes, who were Oirat, were not part of the Mongol expansion under Genghis Khan. Ethnically somewhat distinct, the Dzungar nevertheless were Tibetan Buddhists, just like the Khalkha.
The 18th-century wars to destroy the Dzungar polity and exterminate or scatter its people occurred with the assent and aid of the Khalkha Mongols, who were ethnically close and religiously identical. Some of the Dzungar even fled westward, to joint co-ethnics under Russian rule in the Kalmyk Khanate. The region of Xinjiang that today is labeled “Dzungaria” had very few Mongols after the wars against the Dzungars. Nor did it have many people who we today would call Uygurs. Rather, post-genocide Dzungaria was occupied by nominally Muslim Kazakh and Kirghiz people, while today it has become a magnet for Han and Hui people as Urumqi has become Central Asia’s largest city.
Why am I reviewing all of this? To show how complicated the idea of alliances and affinities based on civilizational identity can be. The reality is that religion and ethnic identity do matter somewhat, but on the medium-scale, they are not as important informatively as on the extremes. Obviously traditionally ethnoreligious groups exhibited ingroup affinity. Buddhist Mongols lived with Buddhist Mongols. Muslim Mongols often assimilated to becoming Turks, while Mongol tribes which had experimented with Islam but eventually became Buddhist lost their Islamic connections. And, on the largest temporal scales and on the margin broader ethnoreligious affiliations matter. Buddhists from as far away as Japan protested to the Taliban when they were mooting the idea of destroying the Bamiyan Buddhas. Christians focus on the persecution of Christians in China. The Mongols, Oirat and Khalkha, became heavily involved in Tibetan politics after their conversion.
A very long post from me, Between the saffron and scimitar, inspired by a lot of the comments we get at Brown Pundits. About six months ago I said something about the Kali Yuga on Twitter in a joking manner, and someone responded: “isn’t that an alt-right meme.” Well, it turns out that some alt-right people are Evola-loving pagans, though I doubt most are. But the idea of the Kali Yuga kind of predates the alt-right in the Hindu tradition, though a lot of people don’t know anything about Hinduism. Similarly, many Indian Hindus (religious or not) have weird perceptions of the origin of any ideas that are also found in Islam…and my name does not help in the way they reflexively respond when I express ideas that might be found in Islam.
But the reality is that it is hard to tease apart Indian culture today from the various influences that domination by Muslims left, even if said Indians are self-consciously anti-Muslim. This is to many people somewhat offensive. I think a good analogy might be some conservative white Americans who don’t want to admit that for many decades white supremacy was considered part and parcel of American patriotism, and constitutive to American nationalism. That arguably has long-term impacts, though unlike many on the Left I do not think that it is an all-pervasive miasma which touches every aspect of American life in 2018.
Pew has a new religious typology out. Not much in the report is surprising.
Here is a surprise to me though: New Age beliefs are more common among the orthodox Christian/religious groups than among the secular subset that is dominated by atheists and agnostics.
There are some interesting distinctions between the “Religion Resisters” and “Solidly Secular.” The latter is 65% male, while the former is majority female. The latter is more educated, wealthier, and more likely to be concentrated in the Northeast and Midwest, while the former is more often in the West. The “Solidly Secular” are the type of people who would be New Atheists. The “Religion Resisters” are actually somewhat more liberal socially and politically issues than the “Solidly Secular.”
Another Pew report suggests that Americans with no religious affiliation have nearly as many Christian beliefs as Europeans who say they are Christian. This is not because those with no religious affiliation in the USA are very Christian. Rather, it’s because European “Christians” are a lot less orthodox than you might expect.
Fracking isn’t profitable at current oil prices. I think the author is probably a little too pessimistic, because technology does get better, and increased crude oil prices will probably show up at some point to fuel further investment.
One of the best things about the fracking boom is I don’t have to listen to friends yammer on about “peak oil” in all-knowing tones. That being said, how are books like Confronting Collapse maintaining such high Amazon star rankings? Is it a fraud? Or do these sorts of pessimistic tomes just always sell well?
A thing I’ve noticed since I’ve shifted to mostly reading on Kindle: I read in a more sequential fashion. Obviously, I can still jump chapters, but the reality is that I don’t do it much. Is it just me?
Adult fiction remained the most popular e-book category–44% of sales in the category were in the digital format–but e-book sales in the segment dropped 14% from 2016, to 108 million units.
E-books have a much smaller share of the adult nonfiction market, 12%, but sales in the segment rose 3% last year, to 38 million units, NPD reported.
The steepest decline in e-book sales last year was in the children’s category, where sales fell 22%. In children’s, the digital format accounted for only 5% of all sales last year. E-book sales were down 8% in the young adult category, falling to 4 million units sold. The format comprised 18% of all young adult unit sales last year.
Makes sense that it would decline in the children’s category. When it comes to reference textbooks, I still go paper. It’s just easier for me to look things up.
Genomic history of the Sardinian population. As Spencer and I alluded to on last week’s episode of The Insight, L. L. Cavalli-Sforza and colleagues did a really good job in their sampling. “Low effective migration rates separate these provinces from a broad area that extends to the mountainous Gennargentu massif region, including inland Ogliastra to the west. The Gennargentu region is also where some of the Sardinian individuals in the HGDP originate (A. Piazza, personal communication). We find that the HGDP Sardinian individuals partially overlap with our dataset and include a subset that clusters near the Ogliastra subpopulation.” That is, the HGDP Sardinians are among the more “EEF” Sardinians.
A Game of Thrones: The Graphic Novel is on sale for Kindle. I don’t even know if I’d want to read a novel in graphic form. But then I’m not a very visual person. Some of the original books actually had a few illustrations. But not that many. For the record, Eddard Stark in my head will always look somewhat like the actor Bill Campbell, not Sean Bean.
Two Psychologists Four Beers. Podcast with Alice Dreger. One of the co-hosts seems to have disappeared for most of the podcast. I assume he was just drinking beer. The last third where Dreger talks about journalism is probably the most novel.
Also, Dreger admits that she probably would have defended Bret Weinstein and Heather Heyer with vigor if she had not been so exhausted and drained by her own academic controversy, as she was forced out of her Northwestern position.
I will add on a personal note that I feel some fatigue and exhaustion because many of my friends in academia expect me to “speak up” about topics that are too politically sensitive for them to broach. I’m OK with doing that…but I have my limits, and other peoples’ third rails are not the burning passion of my life.
To be frank, I’m pretty skeptical about the future of the republic of letters and intellectual life in the West. At least in public. The liberal moment is probably passing. If you have opinions you want to spread, then try to convince those with power. They will make people agree with you.
A review can only pack in so many things. So if there is something missing that seems obvious, it’s probably something that I cut in the interest of space (e.g., the author is not a fan of the emphasis on football and such at many universities, but I didn’t touch on that in the review). The University We Need is a short book, but it’s very dense in ideas and suggestions. Unfortunately, comments on NRO and Twitter indicate many people haven’t really read the review, so they won’t read the book.
Surely one reason I enjoyed the book is that the author is someone with whom I’m coincidently on the same wavelength. I first encountered his work nearly twenty years ago, when I read A History of the Byzantine State and Society, a ~1,000-page survey of the topic. In many ways a scholarly “core dump”, it has stood me in good stead all these years. But at the time I was totally unaware that the author, Warren Treadgold, and I shared broadly similar politics in the grand scheme of things. That is, we were intellectually oriented people who were also not on the Left.
I don’t consider myself a conservative intellectual. I’m just an intellectual who happens to be conservative because the Left terrifies me (I have real personal reasons!). Treadgold’s work similarly is not informed by him being a conservative intellectual. Rather, he’s a scholar whose views default to the Right as opposed to the center or Left because of where the dominant tendency in academia today is.
Speaking of psychology, there are some really good podcasts in that field out. Part of it is there is so much to talk about with the replication crisis. I really enjoyed Two Psychologists Four Beers, for example. Though not surprisingly they sort of still mischaracterize the views and issues of conservatives or non-liberals in academia…there are so few who are “out” and vocal with their politically normal colleagues that people just don’t know what’s going on in their heads and it’s easy to mischaracterize.
This is the week when you follow the #SMBE2018 hashtag on Twitter. I assume a lot of papers are going to come out in the next few weeks after people present at SMBE.
There was some discussion on ancient DNA and archaeology on Twitter. Has ancient DNA changed everything? Or not?
First, I think it’s important to acknowledge that many of the models which have emerged out of ancient DNA are resurrections of older anthropological, archaeological, and historical frameworks, which emphasize migration. But these were long dismissed within many of these fields. Like David Reich in Who We Are and How We Got Here I believe that there was a political rationale for this. As someone who has read deeply in paleoanthropology and history for twenty years, I reject the idea that ancient DNA is actually not that revolutionary because I remember what passed as conventional wisdom 10-20 years ago.
If you haven’t, please consider leaving a 5-star review on iTunes or Stitcher.
I’ve told that you can already read The University We Need on Google Books. I can’t vouch for this, but on Amazon the publication date is July 10th.
I suspect the field of cultural evolution is going to become big in the next ten years, breaking out its relatively rarified ghetto. If you haven’t, I’d recommend The Secret of Our Success by Joe Henrich.
It’s adapted from a chapter of Who We Are and How We Got Here. That chapter is both more subtle and more punchy than the op-ed. Anthropologists will probably dislike it even more than they dislike this op-ed because Reich does not pull punches (though contrary to the impression you might get from the op-ed he clearly prefers to use “ancestry” rather than the word “race”).
There’s not much to say about the op-ed.
I think it’s more interesting to perceive the dynamics of scientific culture at work in the reaction. The Reich lab is an eminent one, and its Diaspora includes other elite institutions now. He is affiliated with Harvard Medical School and the Broad.
Friends of mine who operate outside of human genetics characterize this subfield within genetics as one with sharp elbows and a mafia-like network of pedigree laboratories and superstar professors. It’s probably worse in the explicitly biomedical area, but population geneticists who don’t work on humans still say human population geneticists are different (we’re talking averages here).
There were many criticisms of the op-ed from human population geneticists…but they were subdued, restrained, and often prefaced by praise for Reich’s scientific chops or his generosity as a collaborator. Both true of course. There was also praise.
But the op-ed illustrated the reality of some unpalatable propositions. In Who We Are and How We Got Her David Reich himself makes it clear that some of the ideas he’s mooting are not palatable to him. If it wasn’t clear from the op-ed already.
It also illustrated a truth in academia from what little I’ve seen and experienced within it: it is a highly feudal culture defined by patronage networks and an ordered understanding of the relationship of superiors to subordinates. As they say: “You come at the king, you best not miss.”
If he was someone less connected, less at the peak of his powers, I believe that David Reich’s reputation would be ground up in a sausage machine. This op-ed reminds me of nothing more than Symmachus’ plea for an old way that is fading before the new. Symmachus was rich and famous. He could dissent from the ascendant orthodoxy that was “passing on to better things.” But his class of the old pagan elite was at its dusk.
Most of the more vociferous criticisms of the 0p-ed are coming from anthropologists because it’s a different field with an alternative nobility of blood and status. David Reich can be thought of as an alien warlord who as trespassed the boundaries of their kingdom. But he is also aiming at the very foundations of their rule, so they can do no other but unleash the dogs of war.
Speaking of that book, my review is up at National Review Online. Hope to contribute more in the future to that publication! Doesn’t look like Kevin Williamson is getting fired from The Atlantic, so there’s space in those pages.
I’ll probably talk more in a spoilerish way next week so that people who purchased the book can read it.
The basic outline is that gentrification in East Austin is transforming lower class & lower-middle-class black and Latino neighborhoods into middle and upper-middle-class white neighborhoods. This makes some people really angry because they don’t want their neighborhood to change.
I’ve had some “interesting” discussions about this with locals with deeper roots. It’s fashionable to bemoan gentrification, but when I bring up my experience as an immigrant, and how that naturally results in change and transformation of neighborhoods, people get uncomfortable. The emotions deployed against gentrification aren’t that different from the emotions used against immigration. In many ways, the East Austinites who are being “displaced” can be psychologically analogized to middle and lower-middle-class Trump voters who feel they’re being “displaced.” Both groups feel they are being marginalized by people who are changing the world that their ancestors created with their own labor. And they probably are.
I don’t have a good answer to this. The free-market person in me says that gentrification has to happen, and the neighborhoods are going to change no matter what. But another part of me actually understands the argument by making an analogy to the national level: too much migration into a polity can result in a transformation of its institutions and dispossession of its majority. Pretty soon East Austin will mean something very different from what it has traditionally meant.
If you haven’t had wood ear salad, you haven’t lived. I highly recommend it as one of the major experiences of Sichuan cuisine (and of course don’t go to the place if their green beans are not recommended.
In the spring of 1996, several of my dormmates decided to trek north to the University of Portland, to attend a speech by Stephen Hawking. We were still in that phase where we barely left campus, so intense was our social world. So this was a major undertaking. I don’t recall how we found out about the speech. This is before the internet was a widespread means of distribution of this sort of information (though I think we found out from my dormmate who was a journalism student).
I remember the anticipation and excitement. It was like we were going to a rock concert.
The talk Hawking gave was a typical one about cosmology. He also gave some shout outs to Linus Pauling, who was a native Oregonian.
Like many people, I had read A Brief History of Time. Also, perhaps like most people, I didn’t recall much from that book (I read the book years before going to the talk, in my defense).
Even by the mid-1990s, I was aware that Stephen Hawking was part of a somewhat out of control hype-machine. Though he was an eminent physicist, he was not necessarily the most brilliant physicist since Einstein (one of the claims on one edition of A Brief History of Time I saw at one point). We didn’t have Wikipedia, so I didn’t know about his somewhat messy personal life.
What we did know about Hawking was that he was a man of incredible brilliance who didn’t let his medical condition stop him. We admired him. We admired his achievements. He was heroic. By the time my dormmates and I saw Hawking in the flesh, he was already very frail. The only movement that we could perceive was that you could see he was breathing because of some barely perceptible movement around his neck.
At the end of the talk, people mulled around during the Q & A, trying to get as close as possible. I still have a vivid recollection of seeing Hawking up on the dais, in bright light.
Afterward, on the trip home, we reflected that it seemed unlikely that the great physicist had much time left, seeing as how he was nearly immobile. We felt privileged to be in his presence when he gave a talk. That was enough. Of course, he lived on for more than 20 years.
Ambient temperature is a critical environmental factor for all living organisms. It was likely an important selective force as modern humans recently colonized temperate and cold Eurasian environments. Nevertheless, as of yet we have limited evidence of local adaptation to ambient temperature in populations from those environments. To shed light on this question, we exploit the fact that humans are a cosmopolitan species that inhabits territories under a wide range of temperatures. Focusing on cold perception, which is central to thermoregulation and survival in cold environments, we show evidence of recent local adaptation on TRPM8. This gene encodes for a cation channel that is, to date, the only temperature receptor known to mediate an endogenous response to moderate cold. The upstream variant rs10166942 shows extreme population differentiation, with frequencies that range from 5% in Nigeria to 88% in Finland (placing this SNP in the 0.02% tail of the FST empirical distribution). When all populations are jointly analysed, allele frequencies correlate with latitude and temperature beyond what can be explained by shared ancestry and population substructure. Using a Bayesian approach, we infer that the allele originated and evolved neutrally in Africa, while positive selection raised its frequency to different degrees in Eurasian populations, resulting in allele frequencies that follow a latitudinal cline. We infer strong positive selection, in agreement with ancient DNA showing high frequency of the allele in Europe 3,000 to 8,000 years ago. rs10166942 is important phenotypically because its ancestral allele is protective of migraine. This debilitating disorder varies in prevalence across human populations, with highest prevalence in individuals of European descent, precisely the population with the highest frequency of rs10166942 derived allele. We thus hypothesize that local adaptation on previously neutral standing variation may have contributed to the genetic differences that exist in the prevalence of migraine among human populations today.
The mechanism and adaptive story make sense. They used several methods which corrected/accounted for population structure, and noted that the allele frequency difference was still significantly predicted by variation in latitude (though not temperature).
In the plot above you can see that South Asian populations share allele frequency distributions closer to East Asians, though genetically they are somewhat closer to Europeans. Looking at the haplotype structure this variant looks to be old variation that has been under selection in Eurasia. Additionally if you look at the frequencies it doesn’t look like the sweeps are completing. Since migraines are one correlated side effect that probably makes sense.
The problem I have with this preprint is a simple one. The SNP seems to be in the HGDP browser (it’s in your 23andMe genotype if you have one, I checked). The geographic distribution doesn’t look as clear as it does in the 1000 Genomes data. In particular in the New World populations the latitudinal cline is reversed from what we’d expect.
These sorts of objections are pretty typical. And they authors did do a sophisticated statistical analysis…but sometimes visual inspection of the raw frequencies is still important when the effect is subtle. Over the next decade there is going to be a lot of sophisticated analysis of adaptation, because the low hanging fruit has been picked. But we need to still look over the results with care….
On this week’s The Insight Spencer Wells and I talk about the Indo-Aryan arrival to South Asia. This was recorded very early last summer, and I’m rather unguarded (it’s well before I had the piece published in India Today).
I think 2018 will finally be the year that a lot of South Asia will be “solved.” There has been some foot-dragging on papers and results, but that can only go so long.
All that being said I suppose I should make some suppositions I have arrived at on this topic more explicit, as in a discussion with an Indian friend he admitted had no idea about some of my views, though he reads this weblog when I expressed them. That’s because they are speculative and my confidence in them is weak, though you can infer my opinions if you look very closely.
The figure to the left is from Genomic insights into the origin of farming in the ancient Near East, a paper published about a year and a half ago. You see various South Asian populations being modeled as a mixture of four different source populations. The Onge are an Andaman Islander population (and the closest we can get to the aboriginal peoples of South Asia). Iran_N represents Neolithic Iranians, the canonical “eastern farmer” population. Steppe_EMBA represent Yamnaya pastoralists, who are themselves modeled as a mixture of Eastern European Hunter-Gatherers (EHG) and southern population which has affinities with the Iran_N cluster. EHG in their turn seems to exhibit ancestry from Western European Hunter-Gatherers (WHG), whose heritage dates to the late Pleistocene, and Ancient North Eurasians (ANE), who flourished in Siberia, and contributed ancestry to populations to the west and east (including the ancestors of Native Americans).
When I first saw this specific figure I was incredulous. I had long thought that “Ancient North Indians” (ANI) were a compound of two elements, one related to the farmers of West Asia (Iran_N), and the other steppe Indo-European (Steppe_EMBA/Yamnaya). But the fraction of Yamnaya/Indo-European/Indo-Aryan ancestry seemed far too high.
A few years later I am less certain about my skepticism. The fractions here in the details are debatable. Within the text of the paper, the author admits that the true ancestral populations are probably not represented by the model. But they are close. In most cases, the “Han” ancestry is probably indicative of the fact that the non-ANI component of South Asian ancestry is most closely related to the Onge, but is significantly different nonetheless.
The ratio of Iran_N and Steppe_EMBA is the key. Here is a selection from the paper:
Any way you slice it, a group like the Tiwari Brahmins of Northern India have more Onge-like ancestry than most of the groups in Pakistan. But also observe that the ratio toward Steppe_EMBA is more skewed in them than among even Pathans or Kalash. The Lodhi, a non-upper caste population from Uttar Pradesh in north-central South Asia are more skewed toward Steppe_EMBA than Pathans.
It is important for me to reiterate that the key is to focus on ratios and not exact percentages. Though the Steppe_EMBA fraction did strike me as high, glimmers of these sorts of results were evident in model-based clustering approaches as early as 2010. The population in the list above most skewed toward Iran_N are Cochin Jews. This group has known Middle Eastern ancestry. But next on the list are Brahui, a Dravidian speaking group in Pakistan. There is a north-south cline within Pakistan, with northern populations (Burusho) being skewed toward Steppe_EMBA and southern ones (Sindhi) being skewed toward Iran_N. Additionally, Iranian groups such as Pathans and Baloch likely have had some continuous gene flow with Middle Eastern groups, probably inflating their Iran_N.
Trends I see in the data:
There is a north-south cline within Pakistan with Steppe_EMBA vs. Iran_N
There is a north-south cline within South Asia with Steppe_EMBA vs. Iran_N
There is caste stratification within regions between Steppe_EMBA vs. Iran_N
Though not clear in this table, there are strong suggestions that Indo-European speaking groups tend to be enriched in Steppe_EMBA, all things equal (e.g., the Bengalis in the 1000 Genomes look a lot like the middle-caste Telugus in the 1000 Genomes when you remove the East Asian ancestry…except for a noticeable small fraction of a component which I think points to Indo-European ancestry)
What does this mean in terms of a model of the settlement of South Asian over the past 4,000 years? One conclusion I have come to is that Dravidian speaking groups are not the aboriginal peoples of the subcontinent. Rather, their settlement across much of South Asia is very recent. Almost as recent as Indo-Aryan habitation. In First Farmers the archaeologist Peter Bellwood proposed this model, whereby Indo-Aryans and Dravidians both expanded across South Asia concurrently. Though I think elements of Bellwood’s model that are incorrect, it’s far more correct in my opinion than I believed when I first encountered it.
Why do I believe this?
The Neolithic begins in South India in 3000 BC.
Sri Lanka is Indo-European speaking
The Dravidian languages of South India don’t seem particularly diverged from each other
There is ancestry/caste stratification in South India even excluding Brahmins (e.g., Reddys and Naidus in Andhra Pradesh look somewhat different from Dalits and tribals)
Some scholars claim that there isn’t a Dravidian substrate in the Gangetic plain
R1a1a-Z93, almost certainly associated with Indo-Aryans, is found in South Indian tribal populations
Using LD-based methods researchers are rather sure that the last admixture events between ANI and ASI (“Ancestral South Indians”) populations occurred around ~4,000 years ago
Here is my revised model as succinctly as I can outline it. The northwest fringes of South Asia, today Pakistan, and later to be the home of the Indus Valley Civilization (IVC), was populated by a mix of indigenous populations, a form of ASI, when West Asian agriculturalists arrived ~9,000 years ago from what is today Iran. These were the Iran_N or “eastern farmer” groups. The West Asian agricultural toolkit was serviceable in northwestern South Asia for reasons of climate and ecology, but could not expand further east and south for thousands of years.
There is where the first admixture occurred that led to a population was mixed between ANI and ASI. These people lacked Steppe_EMBA. They were pre-Indo-European. They were almost certainly not all Dravidian speaking. The Burusho people of northern Pakistan, for example, speak a language isolate (in India proper you have Nihali and Kusunda)
By ~3000 BC this proto-South Asian (in a modern sense) population began to expand, while the IVC matured and waxed. Eventually, the IVC waned, fragmented, and disappeared.
Around ~2000 BC, or perhaps somewhat later, Indo-Aryans arrive in South Asia. The situation at this stage in not one of a primordial and static Dravidian India, on which Indo-Aryans place themselves on top. Rather, it’s a dynamic one as the collapse of the IVC has opened up a disordered power vacuum, and a reconfiguration of cultural and sociopolitical alliances.
In the paper above the author alludes to the pervasiveness of both Iran_N and Steppe_EMBA ancestry in South Asia, including in South India. “Indo-European” Y chromosomal lineages are also found among many South Indian groups, albeit at attenuated proportions region-wide. In Peter Turchin’s formulation, I believe that “Indo-Aryan” and “Dravidian” identities became meta-ethnic coalitions in the post-IVC world. Genetically the two groups are different, on average. But some Dravidian populations assimilated and integrated Indo-Aryan tribes and bands, while Indo-Aryans as newcomers assimilated many Dravidian populations.
The reason that the ratio of Iran_N to Steppe_EMBA does not decline monotonically as one goes from west to east along North Indian plain is that Indo-Aryans were not expanding into a Dravidian India. Dravidian India was expanding only somewhat ahead of Indo-Aryan India, and in some places not all at all. In the northwest fringe of South Asia there had long been a settled population of peasants with West Asian ancestry with Iran_N affinities. In contrast to the east the landscape was populated by nomadic tribal populations with ASI affinities. North Indian Brahmins may have more Steppe_EMBA than some populations in Pakistan and more ASI because they descend from Indo-Aryan groups who absorbed indigenous ASI populations as they expanded across the landscape.
Dravidian groups as they expanded also assimilated indigenous populations. This explains some groups with very high fractions of ASI. Their ASI ancestry is a compound, of an old admixture in Northwest India, and also later assimilation in South India. The presence of R1a1a-Z93 in these populations reflects the integration of some originally Indo-Aryan groups into the expanding Dravidian wavefront.
Where does this leave us?
The Indo-Aryan vs. Dravidian dichotomy is not one of newcomers vs. aboriginals. It is of two different sociocultural configurations which came into their current shape in the waning days of the IVC. That is, it is less than 4,000 years old
The two populations were clearly interacting closely around the time of the collapse and disintegration of the IVC and post-IVC societies. There has been gene flow between the two
~4000 years ago ANI and ASI populations existed in their “pure” form, but that is because ASI aboriginals still existed to the south and east of the IVC, while Indo-Aryans were a new intrusive presence in the Indian subcontinent