A few meandering thoughts on Native Americans, Domestication, and Potatoes

While researching last week’s post on “stupid things people do,” I came across a post on weird flute customs found in both Melanesia and a few little tribes in the Amazon rainforest: Gender Ideology Reflected in Flute Symbology of Various New Guinea and South American Cultures:

Specifically, throughout New Guinea and three Central Brazilian cultures, (Mundurucus, Kalapalo, and Kamayura), the flute is endowed with very similar powers and meaning. Each region considers their flutes sacred. They are stored in the men’s homes and females are forbidden to see or play them. In the event that women disobey this order, they can be subject to gang rape or other punishment. Spiritual associations with this instrument are present in all but the culture of the Kalapalo Indians. Ancestral communication is often achieved through the music of flutes as well. However, most importantly, a gender power struggle is represented by the flute, the rituals, and the ceremonies in which the instrument is used.

Of course, sometimes people make claims about parallels that do not exist, and we should be careful about believing claims about other cultures without reading the relevant source material, but assuming it’s true, it’s interesting.

There is a small trace of Melanesian DNA that shows up in the genomes of certain hunter-gatherers in the Amazon; perhaps there is a real cultural link–or perhaps it’s just random.

IMO, the peopling of the Americas will ultimately turn out to have been more complicated than we currently think of it, but unfortunately, we don’t have many DNA samples from Native Americans (because they think geneticists are out to get them). Until that changes, our coverage of Native American genomes is scanty and drawn largely from ancient burials (most of which are controlled by local tribes that don’t allow DNA testing) and from non-American Indians from places like Canada or Mexico.

Even this view, in the Tweet, is probably wrong–if people entered via the Bering Strait, why is the oldest archaeological site at the extreme other end of both continents? Did people run straight to Tierra del Fuego, then turn around and head back up to Montana?

At any rate, I’m not sure how this is “deep roots.” This is their only roots, since they’re from here. Of course, while Native Americans who’ve been here for 12,000 years have “deep” roots, Science would like you to know that “There’s no such thing as a pure European“:

In fact, the German people have no unique genetic heritage to protect. They—and all other Europeans—are already a mishmash, the children of repeated ancient migrations, according to scientists who study ancient human origins. New studies show that almost all indigenous Europeans descend from at least three major migrations in the past 15,000 years, including two from the Middle East. Those migrants swept across Europe, mingled with previous immigrants, and then remixed to create the peoples of today.

Imagine telling the Cheyenne that they aren’t a distinct people with a heritage to protect just because their ancestors got conquered by another Native American tribe 15,000 years ago. Just imagine the sheer, idiotic audacity of it.

But pomo griping about newspaper headlines aside, it seems to me that the level of technological civilization in the Americas was actually pretty high prior to Columbus’s arrival. For example, the civilizations of Mesoamerica, like the Olmecs, were literate and had developed writing and counting systems over two thousand years ago. The cities of the Inca, Maya, and Aztecs, were of course large and impressive. The Natives of America, now oddly more obscure, also had impressive settlements and built large structures like Serpent Mound, Ohio. We tend not to think of them as particularly settled and civilized because by the time white settlers encountered them, their towns had already been destroyed by disease and predation by other tribes who’d gotten horses from the Spaniards.

(The stereotypical horse-riding, tipi-dwelling Indian following herds of buffalo across the Great Plains only emerged after Columbus’s arrival, because horses came from Europe.)

Since the Americas were actually settled pretty late in the scheme of human evolution, I suspect that most Indian groups were actually pretty smart (relatively speaking,) but their technological progress was retarded by a lack of good draft animals. Not because, as some have suggested, domesticable animals simply didn’t exist in the Americas–they do–but because they didn’t have them. Domestication takes time; sneaking up on animals you want to eat is tricky. Cochran has suggested that parasites might have been involved in getting aurochs to be more docile around humans, allowing us to domesticate them and turn them into cattle; the Native Americans hadn’t had the time yet to develop similar parasitic relationships with the local bison. Given another 10 or 40,000 years, though, they might have had time enough to domesticate more of the local fauna.

If the Indians could have adopted old world beasts of burden without losing 90% of their population to epidemic and plague and then getting conquered, there could have been some interesting results a few thousand years down the line.

There’s a similar case in Russia, but more successful.

One of the mysteries (to me, at least, and maybe it’s just ignorance) of European history is why Russia enters so late onto the international. The whole country was apparently founded by the Vikings, the Kievan Rus, which is just one of the weirder bits of historical trivia, and then doesn’t do much of interest until Napoleon invades; then they become important in European politics.

Russians aren’t stupid; Russia has produced plenty of works of art, literature, architecture, etc.

Of course, part of the answer lies in the fact that Russia has an enormous frontier to its east that occasionally spawned barbarian tribes, and so before Russia could do anything on the west, needed to secure the east–and frankly, conquering a bunch of nomadic tribes in Siberia was probably easier than trying to conquer Germany, so Siberia it was. Once Russia had Siberia, then it moved on to conquering Europe.

But my other thought was more mundane: potatoes.

Wheat evolved in the Fertile Crescent–Iraq. It does well in warm climates. It does not do well in cold climates.

Russia is cold.

But potatoes grow really well in central and eastern Europe.

awumsv6
map of potato production

Sure, they aren’t always immune to the local fungi, but when they aren’t blighted, they do really well.

The introduction of a crop that grew well provided the population with more calories more easily, allowing more people to dedicate themselves to non-farming jobs, allowing eastern European countries to become more internationally significant.

Sometimes, a low state of development is just that–the locals just aren’t very good at things like building cities or writing books–and sometimes its due to a lack of local resources, easily changed by the introduction of something new, like horses or potatoes.

Sunken Lands and lost Paradises: Beringia

caribou_feed_on_lichens_and_moss-_the_bird_is_an_alaskan_raven_-_nara_-_550384Beringia is the now-lost land between Alaska and Russia that was, during the last ice age, a vast grassland. It is believed that humans lived here for thousands of years, hunting mammoths, woolly rhinos, bison, and equines. The probably fished as well, just like modern humans in the area.

It was a land of frigid abundance, of herds of giant beasts that probably put the buffalo to shame.

Here is a nice podcast by Razib and Spencer on the lost paradises of Beringia, Sundaland, and Doggerland.

800px-jefferys_-_the_russian_discoveries
Old map of a mysterious, non-existent blob-land

Humans lived in Beringia for thousands of years before they made it into the rest of North America, because the rest of the continent was blocked off, then, by a giant impenetrable ice sheet. This period is therefore referred to as the “Beringia pause” because humans “paused” here during their migration from Siberia to the Americas, but this name obscures the lives and purposes of the people who lived here. They weren’t consciously trying to get to North America and pausing for thousands of years because their way was blocked; they were happily living their lives in a land of abundant resources. We could equally say that Europeans “paused” in Europe for thousands of years before some of them migrated to the Americas, or that anyone on Earth has “paused” in the place they are now.

eskimodna
DNA of the Eskimo/Inuit and related peoples, from Haak et al

According to an article published recently in Nature, The Population History of Siberia since the Pleistocine, by Martin Sikora et 53 other people, these folks in Beringia have their own interesting and complex population history, full of migration and back-migration, conquering, splitting, and joining:

Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of ‘Ancient North Siberians’ who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to ‘Ancient Palaeo-Siberians’ who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name ‘Neo-Siberians’, and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas.

There is a lot of interesting material in this paper (and some nice maps and graphs), but I’m too tired to summarize it all and not lose accuracy, so I encourage you to read it yourself; perhaps the most interesting part involves migration from Alaska to Siberia, across the now-Bering Strait, of people like the Ekven (are these the same as the awkwardly named Evens?)

The polar world is a fascinating circle.

The Evolution of Horses

lascaux-chinese-horseThe ancestors of horses–small, multi-toed quadrupeds–emerged around 50 million years ago, but horses as we know them (and their wild cousins) evolved from a common ancestor around 6 million years ago. Horses in those days were concentrated in North America, but spread via the Bering land bridge to Eurasia and Africa, where they differentiated into zebras, asses, and “wild” horses.

When humans first encountered horses, we ate them. American horses became extinct around 14,000-10,000 years ago, first in Beringia and then in the rest of the continent–coincidentally about the time humans arrived here. The first known transition from hunting horses to herding and ranching them occurred around 6,000 years ago among the Botai of ancient Kazakhstan, not far from the proto-Indo European homeland (though the Botai themselves do not appear to have been pIEs). These herds were still managed for meat, of which the Botai ate tons, until some idiot teenager decided to impress his friends by riding one of the gol-dang things. Soon after, the proto-Indo-Europeans got the idea and went on a rampage, conquering Europe, Iran, and the Indian subcontinent, (and then a little later North and South America, Africa, Australia, and India again). Those horses were useful.

Oddly, though, it appears that those Botai horses are not the ancestors of the modern horses people ride today–but instead are the ancestors of the Przewalski “wild” horse. The Przewalski was though to be a truly wild, undomesticated species, but it appears to have been a kind of domesticated horse* that went feral, much like the mustangs of the wild west. Unlike the mustang, though, the Przewalski is a truly separate species, with 66 chromosomes. Domesticated horses have 64, so the two species cannot produce fertile hybrids. When exactly the Przewalski obtained their extra chromosomes, I don’t know.

*This, of course, depends on the assumption that the Botai horses were “domesticated” in the first place.

Instead, modern, domesticated horses are believed to have descended from the wild Tarpan, though as far as I know, genetic studies proving this have not yet been done. The Tarpan is extinct, but survived up to the cusp of the twentieth century. (Personally, I’m not putting odds on any major tarpan herds in the past couple thousand years having had 100% wild DNA, but I wouldn’t classify them as “feral” just because of a few escaped domestics.)

Thus the horse was domesticated multiple times–especially if we include that other useful member of the equus family, the ass (or donkey, if you’d prefer). The hardworking little donkey does not enjoy its cousin’s glamorous reputation, and Wikipedia reports,

Throughout the world, working donkeys are associated with the very poor, with those living at or below subsistence level.[45] Few receive adequate food, and in general donkeys throughout the Third World are under-nourished and over-worked.[68]

The donkey is believed to have been domesticated from the wild African ass, probably in ancient Nubia (southern Egypt/northern Sudan). From there it spread up the river to the rest of Egypt, where it became an important work animal, and from there to Mesopotamia and the rest of the world.

Wild African asses still exist, but they are critically endangered.

All of the different species within the equus genus, except the domesticated donkey and its wild African cousins, have different numbers of chromosomes:

przewalski: 66
Horse: 64
Donkey: 62
Onager (Persian wild ass): 56
Kulan: 54/55 (??)
Kiang (Asian wild ass): 51/52 (??)
Grevy’s zebra: 46
common zebra: 44
mountain zebra: 42

As far as I know, they can all cross and make mules, but all of these hybrids are infertile except domestic donkey/wild African donkey crosses. (Your only limit is African wild donkeys being endangered.)

I have no idea while equines have so much chromosomal diversity; dogs have been domesticated for much longer than horses, but are still interfertile with wolves and even coyotes (tbf, maybe horses could breed with tarpans.)

Interestingly, domestication causes a suit of changes to a species’ appearance that are not obviously useful. Recently-domesticated foxes exhibit pelt colors and patterns similar to those of domesticated dogs, not wild foxes. We humans have long hair, unlike our chimp-like ancestors. Horses also have long manes, unlike wild zebras, asses, and tarpans. Horses have evolved, then, to look rather like humans.

Also like humans, horses have different male and female histories. Male horses were quite difficult to tame, and so early domesticators only obtained a few male horses. Females, by contrast, were relatively easy to gentle, so breeders often restocked their herds with wild females. As a result, domesticated horses show far more variation in their mitochondrial DNA than their Y chromosomes. The stocking of herds from different groups of wild horses most likely gave rise to 17 major genetic clusters:

From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct phylogenetic clusters. Several of the clusters correspond to breeds and/or geographic areas, notably cluster A2, which is specific to Przewalski’s horses, cluster C1, which is distinctive for northern European ponies, and cluster D1, which is well represented in Iberian and northwest African breeds. A consideration of the horse mtDNA mutation rate together with the archaeological timeframe for domestication requires at least 77 successfully breeding mares recruited from the wild. The extensive genetic diversity of these 77 ancestral mares leads us to conclude that several distinct horse populations were involved in the domestication of the horse.

The wild mustangs of North America might have even more interesting DNA:

The researchers said four family groups (13.8%) with 31 animals fell into haplogroup B, with distinct differences to the two haplogroup L lineages identified.

The closest mitochondrial DNA sequence was found in a Thoroughbred racing horse from China, but its sequence was still distinct in several areas.

The testing also revealed links to the mitochondrial DNA of an Italian horse of unspecific breed, the Yunnan horse from China, and the Yakutia horse from central Siberia, Russia.

Haplogroup B seems to be most frequent in North America (23.1%), with lower frequencies in South America (12.68%) and the Middle East (10.94%) and Europe (9.38%).

“Although the frequency of this lineage is low (1.7%) in the Asian sample of 587 horses, this lineage was found in the Bronze Age horses from China and South Siberia.”

Westhunter suggests that this haplogroup could have originated from some surviving remnant of American wild horses that hadn’t actually been completely killed off before the Spanish mustangs arrived and bred with them. I caution a more prosaic possibility that the Russians brought them while colonizing Alaska and the coast down to northern California. Either way, it’s an intriguing finding.

The horse has been man’s companion for thousands of years and helped him conquer most of the Earth, but the recent invention of internal and external combustion engines (eg, the Iron Horse) have put most horses out to pasture. In effect, they have become obsolete. Modern horses have much easier lives than their hard-working plow and wagon-pulling ancestors, but their populations have shrunk enormously. They’re not going to go extinct, because rich people still like them (and they are still useful in parts of the world where cars cannot easily go,) but they may suffer some of the problems of inbreeding found in genetically narrow dog breeds.

Maybe someday, significant herds of wild horses will roam free again.

 

The Idiocy of Categoric Purity

I realized yesterday that the Left has an odd idea of “purity” that underlies many of their otherwise inexplicable, reality-rejecting claims.

The left has, perhaps unconsciously, adopted the idea that if groups of things within a particular category exist, the groups must be totally independent and not overlap at all.

In the case of genetics, they think that for a genetic group to “exist” and be “real”, it must hail from a single, pure, founding population with no subsequent mixing with other groups. We see this in a recently headline from the BBC: Is this the last of the Aryans? 

Deep in India’s Ladakh region live the Aryans, perhaps the last generation of pure-blooded people and holders of possibly the only untampered gene pool left in the world.

These actually-called-Aryans might be fabulous, interesting people, but there is no way they are more pure and “untampered” than the rest of us. The entire sub-headline is nonsense, because all non-Africans (and some Africans) have Neanderthal DNA. They aren’t even pure Homo sapiens! Africans btw have their own archaic DNA from interbreeding with another, non-Neanderthal, human species. None of us, so far as I know, is a “pure” Homo sapiens.

Besides that, the proto-Indo-European people whom these Aryans are descended from where themselves a fusion of at least two peoples, European hunter-gatherers and a so far as I know untraced steppe-people from somewhere about Ukraine.

Further, even if the Aryans settled in their little villages 4,000 years ago and have had very little contact with the outside world over that time, it is highly unlikely that they have had none.

Meanwhile, out in the rest of the world, there are plenty of other highly isolated peoples: The Sentinelese of North Sentinel Island, for example, who will kill you if you try to set foot on their island. There was a pretty famous case just last year of someone earning himself a Darwin award by trying to convert the Sentinelese.

Now let’s look at that word “untampered.” What on earth does that mean? How do you tamper with a genome? Were the rest of us victims of evil alien experiments with CRSPR, tampering with our genomes?

The Chinese might figure out how to produce “tampered” genomes soon, but the rest of us, all of us in the entire world, have “untampered” genomes.

To be honest, I am slightly flabbergasted at this author’s notion that the rest of the people in the world are walking around with “tampered” genomes because our ancestors married some Anatolian farming people 4,000 years ago.

This strange idea pops up in liberal conversations about “race”, too. Take the recent AAPA Statement on Race and Racism:

Race does not provide an accurate representation of human biological variation. It was never accurate in the past, and it remains inaccurate when referencing contemporary human populations. Humans are not divided biologically into distinct continental types or racial genetic clusters.

But… no one said they did. At least, not since we stopped using Noah’s sons Shem, Ham, and Japheth going their separate ways after the Flood as our explanation for why races exist.

“See, human races are’t descended from Shem, Ham, and Japheth, therefore races don’t exist!”

Two groups of things need not be completely separate, non-overlapping to nonetheless exist. “Pillows” and “cloth” contain many overlapping traits, for example; there are no traits in “cloth” that do not also exist in “pillows.”

Colin Wight on Twitter articulates this beautifully as the “Univariate Fallacy”:

Click the cube. Watch it turn.

This fallacy, when deployed, is commonly done using a single sentence buried within an article or essay couched around a broader narrative on the history of a particular type of oppression, such as sexism. Let me give you some recent examples of this fallacy in action.

You’ll remember this @nature piece arguing that sex is a spectrum and that perhaps there are more then 2 sexes, even though over 99.98% of humans can be classified at birth as being unambiguously male or female. … [Link to piece]

In this piece, they hold off deploying the Univariate Fallacy until the second-to-last sentence of a nearly 3500 word essay.

So if the law requires that a person is male or female, should that sex be assigned by anatomy, hormones, cells or chromosomes, and what should be done if they clash? “My feeling is that since there is not one biological parameter that takes over every other parameter, at the end of the day, gender identity seems to be the most reasonable parameter.”

Please read the whole thread. It is very insightful.

For example, if you look at the so called “big five” personality traits, you find only 10% overlap between men and women. This is why it is usually pretty easy to tell if you are talking to a man or a woman. But if you you look at only one trait at a time, there’s a lot more overlap. So the trick is to take a thing with multiple facets–as most things in the real world are–and claim that because it overlaps in any of its facets with any other thing, that it does not exist. It is not pure.

Are our categories, in fact, random and arbitrary? Is there some reality beneath the categories we use to describe groups of people, like “male” and “female,” “young” and “old,” “black” and “white”? Could we just as easily have decided to use different categories, lumping humans by different criteria, like height or eye color or interest in Transformers, and found these equally valid? Should we refer to all short people as “the short race” and everyone who owns a fedora as “untouchables”?

Liberals believe that the categories came first, were decided for arbitrary or outright evil reasons, bear no relation to reality, and our belief in these categories then created them in the world because we enforced them. This is clearly articulated in the AAPA Statement on Race and Racism:

Instead, the Western concept of race must be understood as a classification system that emerged from, and in support of, European colonialism, oppression, and discrimination. It thus does not have its roots in biological reality, but in policies of discrimination. Because of that, over the last five centuries, race has become a social reality that structures societies and how we experience the world.

Race exists because evil Europeans made it, for their own evil benefit, out of the completely undifferentiated mass of humanity that existed before 1492.

This statement depends on the Univariate Fallacy discussed above–the claim that biological races don’t actually exist is 100% dependent on the UF–and a misunderstanding of the term “social construct,” a term which gets thrown around a lot despite no one understanding what it means.

I propose a different sequence of events, (with thanks to Steven Pinker in the Blank Slate for pointing it out): Reality exists, and in many cases, comes in lumps. Plants, for existence, have a lot in common with other plants. Animals have a lot in common with other animals. Humans create categories in order to talk about these lumps of things, and will keep using their categories so long as they are useful. If a category does not describe things well, it will be quickly replaced by a more effective category.

Meme theory suggests this directly–useful ideas spread faster than non-useful ideas. Useful categories get used. Useless categories get discarded. If I can’t talk about reality, then I need new words.

Sometimes, new information causes us to update our categories. For example, back before people figured out much about biology, fungi were a bit of a mystery. They clearly act like plants, but they aren’t green and they seem to grow parasitically out of dead things. Fungi were basically classed as “weird, creepy plants,” until we found out that they’re something else. It turns out that fungi are actually more closely related to humans than plants, but no one outside of a molecular biologist has any need for a category that is “humans and fungi, but not plants,” so no one uses such a category. There are, additionally, some weird plants, like venus flytraps, that show animal-like traits like predation and rapid movement, and some animals, like sponges, that look more like plants. You would not think a man crazy if he mistook a sponge for a plant, but no one looks at these examples, throws up their hands, and says, “Well, I guess plants and animals are arbitrary, socially-constructed categories and don’t exist.” No, we are all quite convinced that, despite a few cases that were confusing until modern science cleared them up, plants, animals, and fungi all actually exist–moving sponges from the “plant” category to the “animal” category didn’t discredit the entire notion of “plants” and “animals,” but instead improved our classification scheme.

Updating ideas and classification schemes slightly to make them work more efficiently as we get more information about obscure or edge cases in no way impacts the validity of the classification scheme. It just means that we’re human beings who aren’t always 100% right about everything the first time we behold it.

To summarize: reality exists, and it comes in lumps. We create words to describe it. If a word does not describe reality, it gets replaced by a superior word that does a better job of describing reality. Occasionally, we get lucky and find out more information about reality, and update our categories and words accordingly. Where a category exists and is commonly used, therefore, it most likely reflects an actual, underlying reality that existed before the world and caused it to come into existence–not the other way around.

The belief that words create reality is magical thinking and belongs over in Harry Potter and animist religion, where you can cure Yellow Fever by painting someone yellow and then washing off the paint. It’s the same childish thinking as believing that monsters can’t see you if you have a blanket over your head (because you can’t see them) or that Bloody Mary will appear in the bathroom mirror if you turn out the lights and say her name three times while spinning around.

Of course, “white privilege” is basically the “evil eye” updated for the modern age, so it’s not too surprised to find people engaged in other forms of mystical thinking, like that if you just don’t believe in race, it will cease to exist and no one will ever slaughter their neighbors again, just as no war ever happened before 1492 and Genghis Khan never went on a rampage that left 50 million people dead.

“Purity” as conceived of in these examples isn’t real. It doesn’t exist; it never existed, and outside of the simplistic explanations people thought up a few thousand years ago when they had much less information about the world, no one actually uses such definitions. The existence of different races doesn’t depend on Ham and Shem; rain doesn’t stop existing just because Zeus isn’t peeing through a sieve. In reality, men and women are different in a number of different ways that render categories like “man” and “woman” functional enough for 99.99% of your daily interactions. Racial categories like “black” and “white” reflect real-life differences between actual humans accurately enough that we find them useful terms, and the fact that humans have migrated back and forth across the planet, resulting in very interesting historical stories encoded in DNA, does not change this at all.

I’d like to wrap this up by returning to the BBC’s strange article on the Aryans:

I asked Dolma if she was excited over her daughter participating in the festival. She replied that not many outsiders came to Biama, and that it was fun to meet foreigners. But even more importantly, she couldn’t wait to see friends from neighbouring villages, brought together by each year by the festival, as well as the chance to dress up, dance and celebrate. If the future generations continue to hold traditional ceremonies and celebrations and keep their vibrant culture alive, perhaps then, they won’t be the last of the Aryans.

smallisland
Source:  The Economist

One wonders what the author–or the BBC in general–thinks of efforts to keep the British pure or preserve British culture, untouched and unchanged through the millennia. Or is preserving one’s culture only for quaint foreigners whose entertaining exoticism would be ruined if they started acting and dressing just like us? What about those of us in America who think the British have a quaint and amusing culture, and would like it to stick around so we can still be entertained by it? And do the British themselves deserve any say in this, or are they eternally tainted with “impure,” “tampered” bloodlines due to the mixing of bronze-age peoples with Anglo Saxon invaders over a millennium and a half ago, and thus have no right to claim a culture or history of their own?

Goodness, what an idiotic way of looking at the world.

Pygmy-pocalypse?

I just want to highlight this graph I came across yesterday while trying to research archaic introgression in the Igbo:

Populationsize
source

From Whole-genome sequence analysis of a Pan African set of samples reveals archaic gene flow from an extinct basal population of modern humans into sub-Saharan populations, by Lorente-Galdos et al.

There are three versions of this graph in the paper (check the supplemental materials for two of them), all showing about the same thing. It is supposed to be a graph of population size at different times in the past, and the most incredible thing is that for the past 100,000 years or so, the most numerically dominant populations in Africa were the Baka Pygmies, followed by various Bushmen (San) groups. The authors write:

To unravel the ancient demographic history of the African populations that are present in our data set, we used the Pairwise Sequentially Markovian Coalescent (PSMC) model that analyzes the dynamics of the effective population size over time [60]. We included at least one representative of each of the 15 African populations and two Eurasian samples in the analysis (Additional file 1: Figure S7.1) and considered both the classical mutation rate of 2.5 × 10−8 [61] and the 1.2 × 10−8 mutations per bp per generation reported in other analyses [6263]. The demographic trajectories of the sub-Saharan agriculturalist populations are very similar to each other; and only South African Bantu and Toubou individuals differ partly from the rest of sub-Saharan farmer samples; however, their considerable levels of admixture with other North African or hunter-gatherer populations (Fig. 2b) might explain this trend. Therefore, in order to ease visualization, we plotted a Yoruba individual (Yoruba_HGDP00936) and two Ju|‘hoansi individuals as representatives of the sub-Saharan agriculturalist and Khoisan populations, respectively (Fig. 3 and Additional file 1: Figure S7.2 considering a mutation rate of 1.2 × 10−8).

The authors note that the apparent large size of the pygmy groups could have been due to groups splitting and merging and thus getting more DNA variety than they would normally. It’s all very speculative. But still, the Baka Pygmies could have been the absolutely dominant group over central Africa for centuries.

What happened?

 

Book Club: Chinua Achebe’s Things Fall Apart, pt 3/3

 

Chinua_Achebe_-_Buffalo_25Sep2008_crop
Chinua Achebe, Author and Nobel Prize winner

Welcome back to our discussion of Chinua Achebe’s Things Fall Apart. Today I wanted to take a closer look at some of the aspects of traditional Igbo society mentioned in the book.

If you are a regular reader of this blog, you know by now that just as early modern humans (Homo sapiens) mated with Neanderthals and Denisovans somewhere over in Eurasia, some sapiens mated with archaic humans in Africa.

Unfortunately, the state of knowledge about African genomes and especially archaic African genomes is very primitive. Not only does ancient DNA not preserve terribly well in many parts of Africa, but the continent is also rather poor and so people there don’t send their spit to 23 and Me very often to get DNA tested. Thus, sadly, I do not have archaic DNA percents for the Igbo.

WAfricaAdmixture
“Approximate Bayesian computation estimates for the introgressing population across four African populations (Yoruba from Ibadan (YRI), Esan in Nigeria [ESN], Gambian in Western Divisions in the Gambia [GWD], and Mende in Sierra Leone [MSL]),” from Recovering Signals of Ghost Archaic Introgression in African Populations
However, we do have data for their neighbors, the Yoruba, Esan, Mende, and Gambians.

Keep in mind that so far, Eurasians measure about 1-4% Neanderthal and Melanesians about 6% Denisovan, so 10% Ghost in west Africans is a pretty big deal (if you’re into archaic DNA.) The authors of the study estimate that the admixture occurred about 50,000 years ago, which is coincidentally about the same time as the admixture in non-Africans–suggesting that whatever triggered the Out of Africa migration may have also simultaneously triggered an Into Africa migration. 

If you’re not familiar with some of these groups (I only know a little about the Yoruba,) the Esan, Mende, Gambians, and Yoruba are all speakers of languages from the Niger-Congo family (of which the Bantu languages are a sub-set.) The Niger-Congo family is one of the world’s largest, with 1,540 languages and 700 million speakers. It spread within the past 3,000 years from a homeland somewhere in west Africa (possibly Nigeria) to dominate sub-Saharan Africa. As far as I can tell, the Igbo are quite similar genetically to the Yoruba, and the admixture event happened tens of thousands of years before these groups spread and split, so there’s a good chance that the Igbo have similarly high levels of ghost-pop admixture.

Interestingly, a population related to the Bushmen and Pygmies used to dominate central and southern Africa, before the Bantu expansion. While the Bantu expansion and the admixture event are separated by a good 40 or 50 thousand years, this still suggests the possibility of human hybrid vigor.

Edit: A new paper just came out! Whole-genome sequence analysis of a Pan African set of samples reveals archaic gene flow from an extinct basal population of modern humans into sub-Saharan populations:

Here, we examine 15 African populations covering all major continental linguistic groups, ecosystems, and lifestyles within Africa through analysis of whole-genome sequence data of 21 individuals sequenced at deep coverage. We observe a remarkable correlation among genetic diversity and geographic distance, with the hunter-gatherer groups being more genetically differentiated and having larger effective population sizes throughout most modern-human history. Admixture signals are found between neighbor populations from both hunter-gatherer and agriculturalists groups, whereas North African individuals are closely related to Eurasian populations. Regarding archaic gene flow, we test six complex demographic models that consider recent admixture as well as archaic introgression. We identify the fingerprint of an archaic introgression event in the sub-Saharan populations included in the models (~ 4.0% in Khoisan, ~ 4.3% in Mbuti Pygmies, and ~ 5.8% in Mandenka) from an early divergent and currently extinct ghost modern human lineage.

So the ghost population that shows up in the Pygmies the same ghost population as shows up in the Mende? Looks like it.

There’s a lot of interesting stuff in this paper, but I’d just like to highlight this one graph:

Populationsize

I don’t really understand how they compute these things, much less if this is accurate (though their present estimate for the size of the Han looks pretty good,) but assuming it is, we can say a few things: One, before 100,000 years ago, all of the groups–except the Laal of Chad–tracked closely together in size because they were one group. Most of the groups then got smaller simply because they split up. But there seems to have been some kind of really big population bottleneck a bit over a million years ago.

The other really interesting thing is the absolute Pygmy dominance of the mid-10,000-100,000 year range. The authors note:

It is noteworthy that we observed by PSMC a sudden Ne increase in Baka Pygmy around 30 kya. A similar increase was observed in another study that analyzed several Baka and Biaka samples [25]. In addition, this individual presents the highest average genome-wide heterozygosity compared to the rest of samples (Fig. 1b). Nevertheless, such abrupt Ne increase can be attributed to either a population expansion or episodes of separation and admixture [60]. Further analyses at population level are needed to distinguish between these two scenarios.

Until we get more information on the possible Pygmy-cide, let’s get back to Things Fall Apart, for the Igbo of 1890 aren’t their ancestors of 50,000 BC nor the conquerors of central Africa. Here’s an interesting page with information about some of the rituals Achebe wrote about, like the Feast of the New Yams and the Egwugwu ceremony:

 The egwugwu ceremony takes place in order to dispute the guilty side of a crime taken place, similar to our court trials… Nine egwugwu represented a village of the clan, their leader known as Evil Forest; exit the huts with their masks on.

Short page; fast read.

The egwugwu ceremony I found particularly interesting. Of course everyone knows the guys in masks are just guys in masks (well, I assume everyone knows that. It seems obvious,) yet in taking on the masks, they adopt a kind of veil of anonymity. In real life, they are people, with all of the biases of ordinary people; under the mask, they take on the identity of a spirit, free from the biases of ordinary people. It is similar to the official garb worn by judges in other countries, which often look quite silly (wigs on English barristers, for example,) but effectively demarcate a line between normal life and official pronouncements. By putting on the costume of the office, the judge becomes more than an individual.

I have long been fascinated by masks, masquerades, and the power of anonymity. Many famous writers, from Benjamin Franklin to Samuel Clemens, published under pseudonyms. The mask implies falseness–on Halloween, we dress up as things that we are not–but it also allows honesty by freeing us from the threat of retribution.

It is interesting that a small, tightly-knit society where everyone knows everyone and social relations are of paramount importance, like the Igbo, developed a norm of anonymizing judges in order to remove judicial decisions from normal social relations and obligations (as much as possible, anyway). Since most Igbo villages did not have kings or other aristocrats to dictate laws, rule was conducted by notable community members who had effectively purchased or earned noble titles. These nobles got to wear the masks and costumes of the egwgwu.

Ok, so it’s getting late and I need to wrap this up. This moment comes in every post.

I know I haven’t said much about the book itself. The plot, narrative, pacing, structure, writing style, etc. To be honest, that’s because I didn’t enjoy it very much. It was interesting for its content, along with a sense of “I’ve been trying to tell people this and I could have saved myself a lot of time by just pointing them to the book. And if this is a book taught in schools (we didn’t read it in my highschool, but I have heard that many people did,) then why aren’t people more aware of the contents?

What was tribal life like before the Europeans got there? Well, women got beaten a lot. Children were murdered to avenge tribal conflicts. Infant mortality was high. In other words, many things were pretty unpleasant.

And yet, interestingly, much of what we think was unpleasant about them was, in its own way, keeping the peace. As Will (Evolving Moloch) quotes from The Social Structure of Right and Wrong on Twitter:

“Much of the conduct described by anthropologists as conflict management, social control, or even law in tribal and other traditional societies is regarded as crime in modern [nation state] societies.” This is especially clear in the case of violent modes of redress such as assassination, feuding, fighting, maiming, and beating, but it also applies to the confiscation and destruction of property and to other forms of deprivation and humiliation. Such actions typically express a grievance by one person or group against another.

See, for example, when the village burned down Okonkwo’s house for accidentally killing a villager, when they burned down the church for “killing” a deity, or when they took a little girl and killed a little boy in revenge for someone in another village killing one of their women. To the villagers, these were all legal punishments, and the logic of burning down a person’s house if they have killed someone is rather similar to the logic of charging someone a fine for committing manslaughter. Even though Okonkwo didn’t mean to kill anyone, he should have been more careful with his gun, which he knew was dangerous and could kill someone.

Unlike penalties imposed by the state, however, private executions of this kind often result in revenge or even a feud—Moreover, the person killed in retaliation may not be himself or herself a killer, for in these societies violent conflicts between nonkin are virtually always handled in a framework of collective responsibility–or more precisely, collective liability–whereby all members of a social category (such as a family or lineage) are held accountable for the conduct of their fellows.

And, of course, penalties so meted out can be incredibly violent, arbitrary, and selfish, but ignoring that, there’s clearly a conflict when traditional, tribal ways of dealing with problems clash with state-based ways of dealing with problems. Even if everyone eventually agrees that the state-based system is more effective (and I don’t expect everyone to agree) the transition is liable to be difficult for some people, especially if, as in the book, they are punished by the state for enforcing punishments prescribed by their own traditional laws. The state is effectively punishing them for punishing law-breakers, creating what must seem to them a state of anarcho-tyranny.

As for polygamy, Achebe seems to gloss over some of its downsides. From Christakis’s Blueprint: The Origins of a Good Society (h/t Rob Henderson), we have:

Co-wife conflict is ubiquitous in polygynous households… Because the Turkana often choose wives from different families in order to broaden their safety net, they typically do not practice sororal [sister-wives] polygyny… When co-wives are relatives, they can more easily share a household and cooperate… But while sororal polygyny is especially common in cultures in the Americas, general polygyny tends to be the usual pattern in Africa. An examination of ethnographic data from 69 nonsororal polygynous cultures fails to turn up a single society where co-wife relations could be described as harmonious. Detailed ethnographic studies highlight the stresses and fears present in polygynous families, including, for example, wives’ concern that other wives might try to poison their children so that their own children might inherit land or property.

Anyway, let’s wrap this up with a little article on human pacification:

There is a well-entrenched schism on the frequency (how often), intensity (deaths per 100,000/year), and evolutionary significance of warfare among hunter-gatherers compared with large-scale societies. To simplify, Rousseauians argue that warfare among prehistoric and contemporary hunter-gatherers was nearly absent and, if present, was a late cultural invention. In contrast, so-called Hobbesians argue that violence was relatively common but variable among hunter-gatherers. … Furthermore, Hobbesians with empirical data have already established that the frequency and intensity of hunter-gatherer warfare is greater compared with large-scale societies even though horticultural societies engage in warfare more intensively than hunter-gatherers. In the end I argue that although war is a primitive trait we may share with chimpanzees and/or our last common ancestor, the ability of hunter-gatherer bands to live peaceably with their neighbors, even though war may occur, is a derived trait that fundamentally distinguishes us socially and politically from chimpanzee societies. It is a point often lost in these debates.

I think we should read Legal Systems Very Different from Ours for our next book. Any other ideas?

What Ethic Group is This?

 

map

23 and Me map of genetic relatives, rounded. 

An ethnic group is a set of people with a common ancestry, culture, and language. The Han Chinese, at a 1.3 billion strong, are an ethnic group; the Samaritans, of whom there are fewer than a thousand, are also an ethnic group. Ishi was, before his death, an ethnic group of one: the last surviving member of the Yahi people of California. 

We sit within nested sets of genetic relatives:

Family<clan<tribe<ethnic group<race<species<genus

(You are most likely part Homo neanderthalensis, because different species within the Homo genus have interbred multiple times.)

Interestingly, Wikipedia lists African American as an ethnicity on its list of ethnic groups page (as they should, because it is). 

Four or five hundred relatives, from parents and children to fifth cousins, are enough to begin to describe an ethnic group. It certainly looks, based on the map, like I hail from an ethnic group–yet neither Wikipedia nor 23 and Me recognize this group.

According to Wikipedia

Larger ethnic groups may be subdivided into smaller sub-groups known variously as tribes or clans, which over time may become separate ethnic groups themselves due to endogamy or physical isolation from the parent group. Conversely, formerly separate ethnicities can merge to form a pan-ethnicity, and may eventually merge into one single ethnicity. Whether through division or amalgamation, the formation of a separate ethnic identity is referred to as ethnogenesis.

Of course, no one wants to submit their DNA to 23 and Me and get the result “You’re a white person from America.” (Nor “You’re a black person from America.”) We know that. People take these tests to look at their deeper history. 

But focusing only on the past makes it easy to lose sight of the present. You aren’t your ancestors. The world didn’t halt in 1492. I’m no more “British” or “European” than I am “Yamnaya” or “Anatolian farmer.” 

History moves on. New ethnic groups form. The past tells us something about where we’ve been–but not where we’re headed. 

Two Denisovan Admixture Events?

Recent genetic analysis suggests that humans mated with the mysterious Denisovans not once, but twice

Asian genomes carry introgressed DNA from Denisovans and Neanderthals

East Asians show evidence of introgression from two distinct Denisovan populations

South Asians and Oceanians carry introgression from one Denisovan population

I can’t read the whole paper, because it’s paywalled, but if correct, this is quite the change. Previously, only small amounts of Denisovan were detected in East Asians, while large amounts (2-6%) were detected in Oceanians (ie, Melanesians, Papuans, and Australian Aborigines.) 

According to Wikipedia:

Statistical analysis of genomic DNA sequences from different Asian populations indicates that at least two distinct populations of Denisovans existed,[50][51] and that a second introgression event from Denisovans into humans occurred. A study of Han ChineseJapanese and Dai genomes revealed that modern East Asian populations include two Denisovan DNA components: one similar to the Denisovan DNA found in Papuan genomes, and a second that is closer to the Denisovan genome from the Altai cave. These components were interpreted as representing separate introgression events involving two divergent Denisovan populations. South Asians were found to have levels of Denisovan admixture similar to that seen in East Asians, but this DNA only came from the same single Denisovan introgression seen in Papuans.[52]  …

The Denisovans, in case you’re new here, are a human species similar to the Neanderthals who lived… well, we’re not sure exactly where they lived, other than the Altai Cave, Siberia. We also don’t know what they looked like, because we have only found a few of their bones–a finger bone and some teeth–but they might have looked a bit like the Red Deer Cave People. Remarkably, though, these were in good enough condition (Siberia preserves things very well,) to allow scientists to extract sufficient DNA to determine that they are indeed a human species, but one that split from the ancestors of Homo sapiens about 600,000-750,000 years ago, and from the Neanderthals about 200,000 years later. 

Just as Homo sapiens mated with Neanderthals, so Denisovans mated with Neanderthals and Homo sapiens–the human family tree is growing increasingly complex. 

We don’t know exactly where these interbreeding events happened, since we know so little about the Denisovans (at least one of the Neanderthal interbreeding events probably happened in the Middle East, given that all non-Africans [and some Africans] have Neanderthal DNA,) but a clue lies in the DNA of the Negrito peoples. 

The Negritoes are a variety of peoples who live in south east Asia and, like the Pygmies of Africa, are rather short. Some of them, like the Aeta of the Philippines, have almost Papuan levels of Denisovan admixture, while others, like the Onge of India, have almost none. Assuming the Negritos are related to each other and not just isolated examples of island dwarfism, this suggests that the interbreeding event really did take places somewhere east of the major Indonesian islands of Sumatra and Borneo (which probably weren’t islands at the time, but connected to the mainland). The Denisovans may have been clever enough to build boats and cross the Wallace Line, surviving in the more isolated islands of Indonesia and the Philippines. 

On a related note, the article I just linked to from John Hawks, “This is where Scientists Might Find the Next Hobbits,” is truly excellent: 

In May, an international team of scientists led by Thomas Ingicco revealed new archaeological findings from Kalinga, in the northernmost part of Luzon, Philippines. Until now, scientists have mostly assumed that the Philippines were first inhabited by modern humans, only after 100,000 years ago. But the artifacts unearthed by Ingicco and coworkers were much older, more than 700,000 years old. …

Luzon was never connected to the Asian mainland, even when sea level was at its lowest during the Ice Ages. To get there, ancient hominins had to float. Who were they, and how did they get there?

Timeline of ancient Indonesian and Filipino hominin findings, from John Hawks’s article

I recommend you read the whole thing.

What’s all of this Denisovan DNA good for, anyway? Quoting Wikipedia again:

The immune system’s HLA alleles have drawn particular attention in the attempt to identify genes that may derive from archaic human populations. Although not present in the sequenced Denisova genome, the distribution pattern and divergence of HLA-B*73 from other HLA alleles has led to the suggestion that it introgressed from Denisovans into humans in west Asia. As of 2011, half of the HLA alleles of modern Eurasians represent archaic HLA haplotypes, and have been inferred to be of Denisovan or Neanderthal origin.[54] The apparent over-representation of these alleles suggests a positive selective pressure for their retention in the human population. A higher-quality Denisovan genome published in 2012 reveals variants of genes in humans that are associated with dark skin, brown hair, and brown eyes – consistent with features found with Melanesians today.[16] A study involving 40 Han Chinese and 40 people of ethnic Tibetan background identified a region of DNA around the EPAS1 gene that assists with adaptation to low oxygen levels at high altitude found in Tibetans is also found in the Denisovan genome.[55][56] In Papuans, introgressed Neanderthal alleles have highest frequency in genes expressed in the brain, whereas Denisovan alleles have highest frequency in genes expressed in bones and other tissues.[57]

It is a great era in genetics. 

Finnis, Saami, and Fennoscandian DNA

 

800px-Lenguas_finougrias
Distribution of the Finno-Ugric languages

I’ve long wondered which group arrived first in Europe: the Indo-Europeans or the Finno-Ugrics. Most Europeans speak one of the hundreds of languages in the Indo-European family tree, but a few groups speak languages from the mostly Siberian Finno-Ugric branch of the Uralic family.

(Sorry, guys, I’m out of practice writing and these sentences don’t sound good to me, but the only way to improve is to forge ahead, so let’s go.)

Major countries/ethnic groups that speak Finno-Ugric languages include the Finns (obviously,) Saami/Lapps, Hungarians, and Estonians. The most southerly of this family, Hungarian, arrived in the Carpathian Basin within the span of recorded History (in 894 or 895, followed by a few years of warfare to secure their territory,) but the origins of the other European Finno-Ugric languages remains mysterious.

Who arrived first, the Indo Europeans or the Finns? Did the Saami always live in their current homelands, or did they once range much further south or east? Did they migrate here recently or long ago (since the entire area was under ice sheets during the ice age, no one lived there tens of thousands of years ago.)

With the exception of Hungarian, these languages all hail from the far north (especially if you include the Samoyidic languages, which hail from north of Komi on the map,) a cold and forbidding land where herding, hunting, gathering, and fishing have remained the primary way of life until quite recently–the long winters making agriculture very difficult.

Lamnidis et al have a new paper out on Ancient Fennoscandian DNA that sheds a fascinating light on the subject:

Here we analyse ancient genomic data from 11 individuals from Finland and north-western Russia. We show that the genetic makeup of northern Europe was shaped by migrations from Siberia that began at least 3500 years ago. This Siberian ancestry was subsequently admixed into many modern populations in the region, particularly into populations speaking Uralic languages today. Additionally, we show that ancestors of modern Saami inhabited a larger territory during the Iron Age, which adds to the historical and linguistic information about the population history of Finland.

41467_2018_7483_fig1_htmlLet’s cut to the pictures, because they are worth a thousand words:

Just in case you are unclear on the geography, the Modern Saami come from northern part of the Finnoscandian peninsula. Six of the ancient remains came from Bolshoy Oleni Ostrov in the Murmansk Region on the Kola Peninsula–that’s the topmost dot on the map, now in Russia. These remains are very old–dated to about 1610-1436 BC.

Seven remains came from Levänluhta in Isokyrö, Finland, from a more recent burial dated to around 300-800 AD. (Actually, I think Levanluhta is a lake, so  This is the most southwestern burial on the map, in an area where the modern Finns live.

And the remains of two people came from a much more recent Saami cemetery in the Kola peninsula, Chalmny Varre, dating from the 17 or 1800s.

All of this DNA was compared against a variety of reference populations:

41467_2018_7483_fig2_html

(I would just like to pause for a moment to appreciate both the beauty and hard work that went into these graphs.)

PC2 graphs are a little complicated, but what we’re basically looking at (in color) are two different human population axes. They very roughly correlate to north-south (up and down) and east-west, (left to right), because people tend to be more closely related to their neighbors than people thousands of miles away, but there’s another, more fascinating story going on here.

On the right-hand side, we have a cline that maps very nicely to north and south, from the Yukagir–a people from a part of Russia that’s so far to the northeast it’s almost in Alaska–at the top and the Semende of Indonesia and the Atayal, an indigenous Taiwanese group, at the bottom. (Most Taiwanese you meet are either newly arrived Han Chinese or older Han Chinese; the aboriginal Taiwanese are different, but likely the ancestors of Polynesians.)

AsianDNA1
DNA from various Asian peoples

Most east Asian DNA shows up as a blend of these two groups (which we may call roughly polar and tropical). In the chart to the right, taken from Haak et al, the polar DNA is red and the tropical is yellow. So the up-down cline on the right side of the map represents which particular mix of Polar/Tropical DNA these folks have.

On the left side of the graph, we have a farming/hunter-gatherer cline. The first farmers hailed from Anatolia (now Turkey, but that was before the Turks moved to Turkey,) and subsequently spread/conquered most of Europe and probably a few other places, because agriculture was quite successful. So the orange is Middle Easterners; above them are southern Europeans like Albanians and Basques; then the English, French, Hungarians, Finns, etc; and finally some older burials of people with descriptive names like “Eastern Hunter-Gatherer” [EHG] or “Scandinavian Hunter-gatherers” [SHG].

(I have to constantly remind myself what these little abbreviations mean, but The Genetic Prehistory of the Baltic Region probably clears things up a bit:

Similarly, in the Eastern Baltic, where foraging continued to be the main form of subsistence until at least 4000 calBCE15, ceramics technology was adopted before agriculture, as seen in the Narva Culture and Combed Ceramic Culture (CCC). Recent genome-wide data of Baltic pottery-producing hunter-gatherers revealed genetic continuity with the preceding Mesolithic inhabitants of the same region as well as influence from the more northern EHG21,22, but did not reveal conclusively whether there was a temporal, geographical or cultural correlation with the affinity to either WHG or EHG.

The transition from the Late (Final) Neolithic to the Early Bronze Age (LNBA) is seen as a major transformative period in European prehistory, accompanied by changes in burial customs, technology and mode of subsistence as well as the creation of new cross-continental networks of contact seen in the emergence of the pan-European Corded Ware Complex (CWC, ca. 2900–2300 calBCE) in Central2 and north-eastern Europe21.

If you remember your Guns, Germs, and Steel, Turkish farmers had a really hard time getting their wheat to grow up in really cold places like Northern Russia,  Scandinavia and Narva (near the border between Estonia and Russia on the Baltic Sea,) which is why modern Finland is super poor and Turkey and Mexico, where corn was domesticated, are rich–what it doesn’t quite work like that?

Okay.

Anyway.

So most Europeans today are a mix of Anatolian farmers and various European hunter gatherer groups, with exactly how much you got depending a lot on whether the local environment was hospitable to farming. The pure hunter-gatherer genomes therefore show up as “further north” than the mixed, modern genomes of modern French and British folks.

There were additional events besides the Anatolian conquest that shaped modern European genetics–mostly the aforementioned Indo-European conquest–but the Indo-Europeans were at least part hunter-gatherer by DNA (nomadic pastoralists by profession,) so on this scale, their contributions look a lot like the older hunter-gatherer DNA.

So the interesting part of the graph is the middle, where all of the central Eurasian peoples are plotted. The purple band is various Finno-Ugric/Uralic speakers.

Hungarians are solidly in Europe because the ancient conquering Magyars left behind their language, but not much of their DNA (as we’ve discussed previously.) The Nganasan are one of the most thoroughly Siberian peoples you can imagine; they historically survived by hunting reindeer.

The green swaths (light and dark teal) are mostly Turkic-language speaking peoples; the Turkic peoples originated near Mongolia/Korea and spread out from there, mostly absorbing the DNA of whomever they encountered and passing on their language. The authors have also included Mongolian (which is not in the Turkic language family) in the light green group and some Caucuses groups in the dark teal.

Interestingly, the Yukaghir language (far upper right) is (according to Wikipedia,) potentially in the greater Finno-Ugric/Uralic family:

The relationship of the Yukaghir languages with other language families is uncertain, though it has been suggested that they are distantly related to the Uralic languages, thus forming the putative Uralic–Yukaghir language family.[5]

Based on the genetics, I’d say it looks very likely that the ancestors of Uralic-speaking Nganasan and the Yukagirs were conversing in some sort of mutually intelligible language. Unfortunately, Yukaghir has very few speakers and is likely to die, so there’s not much time to research it.

Finally in the Light Teal we have some groups from Pakistan/Afghanistan, like the Balochi.

(Note that all of the colors used in these studies are arbitrary; DNA doesn’t really have a color.)

So where do our ancient DNA remains fall on this graph?

Today, the Levanluhta site is in Finland, surrounded solidly by Finns (and maybe some random Scandinavians; who knows;) in 300-800 AD, the population was almost identical to modern Saami. So even though Saami and Finns both speak Finno-Ugric languages, the Finns replaces the Saami in this area sometime in the past 1,500 years or so.

One Levanlughta skeleton is an exception–the one marked Levanlughta_B; it is clearly closer to the Finns and English on this graph, but deeper mathematical analysis disputes this conclusion:

One of the individuals from Levänluhta (JK2065/Levänluhta_B) rejects a cladal position with modern Saami to the exclusion of most modern Eurasian populations. This individual also rejects a cladal position with Finns. We analysed low coverage genomes from four additional individuals of the Levänluhta site using PCA (Supplementary Figure 3), confirming the exclusive position of Levänluhta_B compared to all other six individuals (including the four low-coverage individuals) from that site, as is consistent with the ADMIXTURE and qpAdm results. The outlier position of this individual cannot be explained by modern contamination, since it passed several tests for authentication (see Methods) along with all other ancient individuals. However, no direct dating was available for the Levänluhta material, and we cannot exclude the possibility of a temporal gap between this individual and the other individuals from that site.

In other words, it is a mystery.

The remains from Chalmny Varre, which we know was a Saami cemetery, unsurprisingly cluster with the other Saami.

The Bolshoy remains, though, are quite interesting. They are shifted slightly in the direction of the ancient hunter-gatherers (perhaps their descendants, if still around, have mixed a bit with the agriculturalists.) Their physical location is about as far east as the Red Squares (ethnic Russians,) yet the more closely resemble the Mansi or the Selkups. (The modern Mansi live here; the modern Selkups live nearby.)

Getting down to the bar graphs, we see this data presented in a different way.

There are three groups that we can see contributing to most modern Europeans–Farmers, represented by the Orange LBK DNA; exclusively Indo-European, Green, notably not found in the Basque; and hunter-gatherers in Dark Blue. (Note that the ancestors of the Indo-Europeans hailed from the Central Eurasian steppes and so their DNA could have gotten around there, too.)

The modern Saami also have a Purple component to their DNA, which finds its highest expression in the Nganasan of far eastern polar Russia.

So the oldest burials–the Bolshoy–show no agricultural DNA. They are hunter-gatherers+Siberians, with a touch of Indo-European (probably from a steppe population that might have contributed to the Indos as well) and a bit they share with… the Karitiana of Brazil? Well, the Native Americans did descend from Paleo Siberians, so some genetic relatedness is expected.

The more recent burials, which cluster with the modern Saami, all show agricultural DNA–probably due to marrying a few of the local Finns/Russians who carry some agricultural DNA (who are almost genetically identical on this scale) rather than a pure LBK agriculturalist.

Here we see why the one outlier, Levanlughta_B, doens’t group with the Finns, either–modern Finns and Russians have some of that Nganasan-style Siberian DNA (probably from the same process that gifted Finnish/Russian DNA to the Saami), but Levanlughta_B doesn’t. Levanlughta_B looks more like the Baltic BA sample (Baltic Bronze Age.) Perhaps this individual was just a merchant, traveler, or lost–or represents a stage before the modern Finnish population had been produced.

The Finnish population itself is interesting, because it is genetically very similar to the Russian, but obviously speaks a language far more closely related to Saami (Lapp) than anything in the Indo-European tree. While it is therefore likely that the Finns replaced the Saami in the area around Lake Levanlughta, it seems also probable that in the process, they absorbed a large number of Uralic-speaking people. Who conquered (or married) whom? Did an ancient Balto-Slavic population move into what is now Finland, marry the local Saami girls, and adopt their language? Did an ancient Siberian population speaking a Uralic language conquer some ancient group of Russians, take their women, pass on their Uralic language, and later move into Finland and drive out the locals? Or perhaps something even more complicated occurred.

As for the Bolshoy, are they related (closely) to the modern Saami, or are they a group that simply died out?

The paper goes on:

 While the Siberian genetic component presented here [Purple] has been previously described in modern-day populations from the region1,3,9,10, we gain further insights into its temporal depth. Our data suggest that this fourth genetic component found in modern-day north-eastern Europeans arrived in the area before 3500 yBP. It was introduced in the population ancestral to Bolshoy Oleni Ostrov individuals 4000 years ago at latest, as illustrated by ALDER dating using the ancient genome-wide data from the Bolshoy samples. The upper bound for the introduction of this component is harder to estimate. The component is absent in the Karelian hunter-gatherers (EHG)3 dated to 8300–7200 yBP as well as Mesolithic and Neolithic populations from the Baltics from 8300 yBP and 7100–5000 yBP respectively8

Karelia is a region that crosses the border between Finland and Russia, so it is significant that this Siberian component isn’t found in ancient Karelian hunter-gatherers. Of course, the Siberians could have just been further north, however, the authors note that we have archaeological evidence of the spread of the Bolshoy people:

The large Nganasan-related component in the Bolshoy individuals from the Kola Peninsula provides the earliest direct genetic evidence for an eastern migration into this region. Such contact is well documented in archaeology, with the introduction of asbestos-mixed Lovozero ceramics during the second millennium BC50, and the spread of even-based arrowheads in Lapland from 1900 BCE51,52. Additionally, the nearest counterparts of Vardøy ceramics, appearing in the area around 1,600-1,300 BCE, can be found on the Taymyr peninsula, much further to the East51,52. Finally, the Imiyakhtakhskaya culture from Yakutia spread to the Kola Peninsula during the same period24,53. Contacts between Siberia and Europe are also recognised in linguistics. The fact that the Nganasan-related genetic component is consistently shared among Uralic-speaking populations, with the exceptions of absence in Hungarians and presence in the non-Uralic speaking Russians, makes it tempting to equate this genetic component with the spread of Uralic languages in the area.

The authors qualify this with a bit of “it’s complicated; people move around a lot,” but basically it’s People: not pots.

That was an enjoyable read; I look forward to the next paper from these folks.

Neanderthal DNA–hey!–what is it good for?

Quite a bit.

First, a bit of history:

neanderthalmap
map of Neanderthal DNA in humans

It appears that there were (at least) 3 main cross-breeding events with Neanderthals. The first event most likely happened when one small band of humans had left Africa and ventured into the Middle East, where Neanderthals were living. The DNA acquired from that partnership can be found in all modern non-Africans, since they are all descended from this same group. (Since there has also been back-migration from the Middle East into Africa sometime in the past 70,000 years, many African groups also have a small amount of this DNA.)

Soon after, the group that became the Melanesians, Papuans, and Aborigines split off from the rest and headed east, where they encountered–and interbred with–the mysterious Denisovans, a third human species that we know mostly from DNA. Various sources claim this happened before the second neanderthal inter-breeding event, but just looking at the amount of admixed neanderthal in Oceanans suggests this is wrong.

Meanwhile, the rest of the non-African humans, probably still living in the Middle East or Eurasian Steppe, encountered a second band of Neanderthals, resulting in a second admixture event, shared by all Asians and Europeans, but not Melanesians &c. Then the Asians and Europeans went their separate ways, and the Asians encountered yet a third group of Neanderthals, giving them the highest rates of Neanderthal ancestry.

nature-siberian-neanderthals-17.02.16-v2

During their wanderings, some of these Asians encountered Melanesians, resulting in a little Denisovan DNA in today’s south Asians (especially Tibetans, who appear to have acquired some useful adaptations to Tibet’s high altitude from ancient Denisovans.)

There were other interbreeding events, including a much older one that left homo sapiens DNA in Neanderthals, and one that produced Denny, a Neanderthal/Denisovan hybrid. There were also interbreeding events in Africa, involving as-yet unidentified hominins. (In the human family tree to the right/above, Melanesians are included within the greater Asian clade.)

Who married whom? So far, we’ve found no evidence of Neanderthal mitochondrial DNA–passed from mothers to their children–in modern humans, so the pairings most likely involved Neanderthal men and human women. But we have also found extremely little Neanderthal DNA on the Y chromosome–so it is likely that they only had female children, or any male children they had were infertile.

Anthropogenesis-DenisovaAlleleMapInterestingly, we find higher amounts of Neanderthal DNA in older skeletons, like the 40,000 year old Tianyuan Man, or this fellow from Romania with 10% Neanderthal DNA, than in modern humans. Two potential explanations for the decrease: later mixing with groups that didn’t have Neanderthal DNA resulted in dilution, or people with more Neanderthal DNA just got out-competed by people with less.

Given the dearth of DNA on the Y chromosome and the number of diseases linked to Neanderthal DNA, including Lupus, Crohn’s, cirrhosis, and Type-2 diabetes, the fact that morphological differences between Sapiens and Neanderthals are large enough that we classify them as different species, and the fact that Neanderthals had larger craniums than Sapiens but Sapiens women attempting to give birth to hybrid children still had regular old Sapiens pelvises, gradual selection against Neanderthal DNA in humans seems likely.

However, the Neanderthals probably contributed some useful DNA that has been sorted out of the general mix and come down the ages to us. For example, the trait that allows Tibetans to live at high altitudes likely came from a Denisovan ancestor:

Researchers discovered in 2010 that Tibetans have several genes that help them use smaller amounts of oxygen efficiently, allowing them to deliver enough of it to their limbs while exercising at high altitude. Most notable is a version of a gene called EPAS1, which regulates the body’s production of hemoglobin. They were surprised, however, by how rapidly the variant of EPAS1spread—initially, they thought it spread in 3000 years through 40% of high-altitude Tibetans, which is the fastest genetic sweep ever observed in humans—and they wondered where it came from.

Modern humans have Neanderthal DNA variants for keratin (a protein found in skin, nails, hair, etc.,) and UV-light adaptations that likely helped us deal with the lower light levels found outside Africa. There’s circumstantial evidence that microcephalin D could have Neanderthal origins (it appeared about 37,000 years ago and is located primarily outside of Africa,) but no one has found microcephalin D in a Neanderthal, so this has not been proven. (And, indeed, another study has found that Neanderthal DNA tends not to be expressed in the brain.)

Yet on the other hand, Neanderthal admixture affected sapiens’ skull shapes:

Here, using MRI in a large cohort of healthy individuals of European-descent, we show that the amount of Neanderthal-originating polymorphism carried in living humans is related to cranial and brain morphology. First, as a validation of our approach, we demonstrate that a greater load of Neanderthal-derived genetic variants (higher “NeanderScore”) is associated with skull shapes resembling those of known Neanderthal cranial remains, particularly in occipital and parietal bones. Next, we demonstrate convergent NeanderScore-related findings in the brain (measured by gray- and white-matter volume, sulcal depth, and gyrification index) that localize to the visual cortex and intraparietal sulcus. This work provides insights into ancestral human neurobiology and suggests that Neanderthal-derived genetic variation is neurologically functional in the contemporary population.

(Not too surprising, given Neanderthals’ enormous craniums.)

Homo sapiens also received Neanderthal genes affecting the immune system, which were probably quite useful when encountering new pathogens outside of Africa, and genes for the “lipid catabolic process,”[19] which probably means they were eating new, fattier diets that Neanderthals were better adapted to digest.

Even Neanderthal-derived traits that today we cast as problems, like Type II Diabetes and depression, might have been beneficial to our ancestors:

“Depression risk in modern human populations is influenced by sunlight exposure, which differs between high and low latitudes, and we found enrichment of circadian clock genes near the Neanderthal alleles that contribute most to this association.”

Why would we find an association between Neanderthal DNA and circadian clock genes? Neanderthals had thousands of years more exposure to Europe’s long nights and cold winters than homo Sapiens’; it is unlikely that they developed these adaptations in order to become less well-adapted to their environment. It is more likely that Neanderthals downregulated their activity levels during the winter–to put it colloquially, they hibernated.

No problem for furry hunter-gatherers who lived in caves–much more problematic for information age workers who are expected to show up at the office at 9 am every day.

Type II diabetes affects digestion by decreasing the production of insulin, necessary for transporting converting carbs (glucose) into cells so it can be transformed into energy. However, your body can make up for a total lack of carbs via ketosis–essentially converting fats into energy.

Our hunter-gatherer ancestors–whether Neanderthal or Sapiens–didn’t eat a lot of plants during the European and Siberian winters because no a lot of plants grow during the winter. If they were lucky enough to eat at all, they ate meat and fat, like the modern Inuit and Eskimo.

And if your diet is meat and fat, then you don’t need insulin–you need ketosis and maybe some superior lipid digestion. (Incidentally, the data on ketogenic diets and type II diabetes looks pretty good.)

In sum, Neanderthal and Denisovan DNA, while not always useful, seems to have helped Homo sapiens adapt to colder winters, high altitudes, new pathogens, new foods, and maybe changed how we think and perceive the world.