Book Club: The 10,000 Year Explosion pt. 6: Expansion

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Welcome back to the Book Club. Today we’re discussing chapter 6 of Cochran and Harpending’s The 10,000 Year Explosion: Expansions

The general assumption is that the winning advantage is cultural–that is to say, learned. Weapons, tactics, political organization, methods of agriculture: all is learned. The expansion of modern humans is the exception to the rule–most observers suspect that biological difference were the root cause of their advantage. … 

the assumption that more recent expansions are all driven by cultural factors is based on the notion that modern humans everywhere have essentially the same abilities. that’s a logical consequence of human evolutionary stasis” If humans have not undergone a significant amount of biological change since the expansion out of Africa, then people everywhere would have essentially the same potentials, and no group would have a biological advantage over its neighbors. But as we never tire of pointing out, there has been significant biological change during that period.

I remember a paper I wrote years ago (long before this blog) on South Korea’s meteoric economic rise. In those days you had to actually go to the library to do research, not just futz around on Wikipedia. My memory says the stacks were dimly lit, though that is probably just some romanticizing. 

I poured through volumes on 5 year economic plans, trying to figure out why South Korea’s were more successful than other nations’. Nothing stood out to me. Why this plan and not this plan? Did 5 or 10 years matter? 

I don’t remember what I eventually concluded, but it was probably something along the lines of “South Korea made good plans that worked.” 

People around these parts often criticize Jared Diamond for invoking environmental explanations while ignoring or directly counter-signaling their evolutionary implications, but Diamond was basically the first author I read who said anything that even remotely began to explain why some countries succeeded and others failed. 

Environment matters. Resources matter. Some peoples have long histories of civilization, others don’t. Korea has a decently long history. 

Diamond was one of many authors who broke me out of the habit of only looking at explicit things done by explicitly recognized governments, and at wider patterns of culture, history, and environment. It was while reading Peter Frost’s blog that I first encountered the phrase “gene-culture co-evolution,” which supplies the missing link. 

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IQ by country

South Korea does well because 1. It’s not communist and 2. South Koreans are some of the smartest people in the world. 

I knew #1, but I could have saved myself a lot of time in the stacks if someone had just told me #2 instead of acting like SK’s economic success was a big mystery. 

The fact that every country was relatively poor before industrialization, and South Korea was particularly poor after a couple decades of warfare back and forth across the peninsula, obscures the nation’s historically high development. 

For example, the South Korean Examination system, Gwageo, was instituted in 788 (though it apparently didn’t become important until 958). Korea has had agriculture and literacy for a long time, with accompanying political and social organization. This probably has more to do with South Korea having a relatively easy time adopting the modern industrial economy than anything in particular in the governments’ plans. 

Cochran has an interesting post on his blog on Jared Diamond and Domestication: 

In fact, in my mind the real question is not why various peoples didn’t domesticate animals that we know were domesticable, but rather how anyone ever managed to domesticate the aurochs. At least twice. Imagine a longhorn on roids: they were big and aggressive, favorites in the Roman arena. … 

The idea is that at least some individual aurochs were not as hostile and fearful of humans as they ought to have been, because they were being manipulated by some parasite. … This would have made domestication a hell of a lot easier. …

The beef tape worm may not have made it through Beringia.  More generally, there were probably no parasites in the Americas that had some large mammal as intermediate host and Amerindians as the traditional definite host. 

They never mentioned parasites in gov class. 

Back to the book–I thought this was pretty interesting:

One sign of this reduced disease pressure is the unusual distribution of HLA alleles among Amerindians. the HLA system … is a group of genes that encode proteins expressed on the outer surfaces of cells. the immune system uses them to distinguish the self from non-self… their most important role is in infections disease. … 

HLA genes are among the most variable of all genes. … Because these genes are so variable, any two humans (other than identical twins) are almost certain to have a different set of them. … Natural selection therefore favors diversification of the HLA genes, and some alleles, though rare, have been persevered for a long time. In fact, some are 30 million years old, considerably older than Homo sapiens. …

But Amerindians didn’t have that diversity. Many tribes have a single HLA allele with a frequency of over 50 percent. … A careful analysis of global HLA diversity confirms continuing diversifying selection on HLA in most human populations but finds no evidence of any selection at all favoring diversity in HLA among Amerindians.

The results, of course, went very badly for the Indians–and allowed minuscule groups of Spaniards to conquer entire empires. 

The threat of European (and Asian and African) diseases wiping out native peoples continues, especially for “uncontacted” tribes. As the authors note, the Surui of Brazil numbered 800 when contacted in 1980, but only 200 in 1986, after tuberculosis had killed most of them. 

…in 1827, smallpox spared only 125 out of 1,600 Mandan Indians in what later became North Dakota.

The past is horrific. 

I find the history ancient exploration rather fascinating. Here is the frieze in Persepolis with the okapi and three Pygmies, from about 500 BC.

The authors quote Joao de Barros, a 16th century Portuguese historian: 

But it seems that for our sins, or for some inscrutable judgment of God, in all the entrances of this great Ethiopia we navigate along… He has placed a striking angel with a flaming sword of deadly fevers, who prevents us from penetrating into the interior to the springs of this garden, whence proceed these rivers of gold that flow to the sea in so many parts of our conquest.

Barros had a way with words. 

It wasn’t until quinine became widely available that Europeans had any meaningful success at conquering Africa–and even still, despite massive technological advantages, Europeans haven’t held the continent, nor have they made any significant, long-term demographic impact. 

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Source: National Geographic

The book then segues into a discussion of the Indo-European expansion, which the authors suggest might have been due to the evolution of a lactase persistence gene. 

(Even though we usually refer to people as “lactose intolerance” and don’t regularly refer to people as “lactose tolerant,” it’s really tolerance that’s the oddity–most of the world’s population can’t digest lactose after childhood.

Lactase is the enzyme that breaks down lactose.)

Since the book was published, the Indo-European expansion has been traced genetically to the Yamnaya (not to be confused with the Yanomamo) people, located originally in the steppes north of the Caucasus mountains. (The Yamnaya and Kurgan cultures were, I believe, the same.) 

An interesting linguistic note: 

Uralic languages (the language family containing Finnish and Hungarian) appear to have had extensive contact with early Indo-European, and they may share a common ancestry. 

I hope these linguistic mysteries continue to be decoded. 

The authors claim that the Indo-Europeans didn’t make a huge genetic impact on Europe, practicing primarily elite dominance–but on the other hand, A Handful of Bronze-Age Men Could Have Fathered 2/3s of Europeans:

In a new study, we have added a piece to the puzzle: the Y chromosomes of the majority of European men can be traced back to just three individuals living between 3,500 and 7,300 years ago. How their lineages came to dominate Europe makes for interesting speculation. One possibility could be that their DNA rode across Europe on a wave of new culture brought by nomadic people from the Steppe known as the Yamnaya.

That’s all for now; see you next week.