Book Club: The 10,000 Year Explosion, Part 3

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The spread of agriculture

Welcome back to the Book Club. Today we’re reading Chapter 3: Agriculture, from Cochran and Harpending’s The 10,000 Year Explosion: How Civilization Accelerated Human Evolution.

One of my fine readers asked for “best of” recommendations for Cochran and Harpending’s blog, West Hunter. This is a good question, and as I have not yet found a suitable list, I thought I would make my own.

However, the West Hunter is long, so I’m only doing the first year for now:

My friend the Witch Doctor:

Only a handful of Herero shared my skepticism about witchcraft. People in the neighborhood as well as several other employees were concerned about Kozondo’s problem. They told me that he had to be taken to a well known local witch doctor. “Witch doctor” I said, “you all have been watching too many low budget movies. We call them traditional healers these days, not witch doctors”. They all, including Kozondo, would have none of it. “They are bad and very dangerous people, not healers” he said. It quickly became apparent that I was making a fool of myself trying to explain why “traditional healer” was a better way to talk than “witch doctor”. One of our group had some kind of anti-anxiety medicine. We convinced Kozondo to try one but it had no effect at all. Everyone agreed that he must consult the witch doctor so we took him. …

That evening we had something like a seminar with our employees and neighbors about witchcraft. Everyone except the Americans agreed that witchcraft was a terrible problem, that there was danger all around, and that it was vitally important to maintain amicable relations with others and to reject feelings of anger or jealousy in oneself. The way it works is like this: perhaps Greg falls and hurts himself, he knows it must be witchcraft, he discovers that I am seething with jealousy of his facility with words, so it was my witchcraft that made him fall. What is surprising is that I was completely unaware of having witched him so he bears me no ill will. I feel bad about his misfortune and do my best to get rid of my bad feelings because with them I am a danger to friends and family. Among Herero there is no such thing as an accident, there is no such thing as a natural death, witchcraft in some form is behind all of it. Did you have a gastrointestinal upset this morning? Clearly someone slipped some pink potion in the milk. Except for a few atheists there was no disagreement about this. Emotions get projected over vast distances so beware.

Even more interesting to us was the universal understanding that white people were not vulnerable to witchcraft and could neither feel it nor understand it. White people literally lack a crucial sense, or part of the brain. An upside, I was told, was that we did not face the dangers that locals faced. On the other hand our bad feelings could be projected so as good citizens we had to monitor carefully our own “hearts”.

Amish Paradise:

French Canadian researchers have shown that natural selection has noticeably sped up reproduction among the inhabitants of Île aux Coudres, an island in the St. Lawrence River –  in less than 150 years. Between 1799 and 1940, the age at which women had their first child dropped from 26 to 22, and analysis shows this is due to genetic change.

… Today the French of Quebec must  differ significantly (in those genes that influence this trait)  from people in France, which has had relatively slow population growth.  …

The same must be the case for old American types whose ancestors – Puritans, for example – arrived early and went through a number of high-fertility generations in colonial days.  It’s likely the case for the Mormons, who are largely descended from New Englanders. I’ve heard of odd allele frequencies  in CEU  (involving FSH) that may relate to this.

Something similar must be true of the Boers as well.

I would guess that a similar process operated among the first Amerindians that managed to get past  the ice in North America.  America south of the glaciers would have been a piece of cake for anyone tough enough to make a living as a hunter in Beringia – lush beyond belief, animals with no experience of humans.

Six Black Russians:

(Black Russians are, I think, an alcoholic beverage.)

Every now and then, I notice someone, often an anthropologist,  saying that human cognitive capability just has to be the same in all populations.  According to Loring Brace, “Human cognitive capacity , founded on the ability to learn a language, is of equal survival value to all human groups, and consequently there is no valid reason to expect that there should be average differences in intellectual ability among living human populations. ”

There are a lot of ideas and assumptions in that quote, and as far as I can tell, all of them are wrong.  …

Populations vary tremendously in the fraction that contributes original work in science and technology – and that variation mostly agrees with the distribution of IQ.

And Your Little Dog, Too!

As I have mentioned before,  the mtDNA of European hunter-gathers seems to be very different from that of modern Europeans. The ancient European mtDNA pool was about 80% U5b – today that lineage is typically found at 10% frequency or lower, except in northern Scandinavia. Haplogroup H, currently the most common in Europe, has never been found in early Neolithic or  pre-Neolithic Europeans.  …

Interestingly, there is a very similar  pattern in canine mtDNA.  Today Europeans dogs fall into four haplotypes: A (70%), B(16%), C (6%), and D(8%).  But back in the day, it seems that the overwhelming majority of dogs (88%)  were type C,  12% were in group A, while B and D have not been detected at all.

Lewontin’s Argument 

(always bears re-addressing)

Richard Lewontin argued that since most (> 85%) genetic variation in humans is within-group, rather than between groups, human populations can’t be very different. Of course, if this argument is valid, it should apply to any genetically determined trait. Thus the  variation in skin color within a population should be larger than the skin color differences between populations – except that it’s not. The difference in skin color between Europeans and Pygmies is large, so large that there is no overlap at all.

The Indo-European Advantage

There is a large region of homogeneity on European haplotypes with the mutation [for lactose tolerance], telling us that it has arisen to high frequency within the last few thousand years. …

In a dairy culture where fresh milk was readily available, children who could drink it obtained about 40% more calories from milk than children who were not LT.

Consider that 1 Liter of cow’s milk has

* 250 Cal from lactose
* 300 Cal from fat
* 170 Cal from protein

or 720 Calories per liter. But what if one is lactose intolerant? Then no matter whether or not flatulence occurs that person does not get the 250 Calories of lactose from the liter of milk, but only gets 470.

The Hyperborean Age

I was contemplating Conan the Barbarian, and remembered the essay that Robert E. Howard wrote about the  background of those stories – The Hyborian Age.  I think that the flavor of Howard’s pseudo-history is a lot more realistic than the picture of the human past academics preferred over the past few decades. …

Given the chance (sufficient lack of information), American anthropologists assumed that the Mayans were peaceful astronomers. Howard would have assumed that they were just another blood-drenched snake cult: who came closer? …

Most important, Conan, unlike the typical professor, knew what was best in life.

Class, Caste, and Genes: 

If there is any substantial heritability of merit, where merit is whatever leads to class mobility, then mobility ought to turn classes into hereditary castes surprisingly rapidly.

A start at looking into genetic consequences of meritocracy is to create the simplest possible model and follow its implications. Consider free meritocracy in a two class system, meaning that each generation anyone in the lower class who has greater merit than someone in the upper class immediately swaps class with them. …

Back to the book. Chapter 3: Agriculture: The Big Change

This chapter’s thesis is the crux of the book: agriculture simultaneously exposed humans to new selective pressured and allowed the human population to grow, creating a greater quantity of novel mutations for natural selection to work on.

Sixty thousand years ago, before the expansion out of Africa, there were something like a quarter of a million modern humans. By the Bronze Age, 3,000 years ago that number was roughly 60 million. 

Most random mutations fall somewhere between “useless” and “kill you instantly,” but a few, like lactase persistence, are good. I’m just making up numbers, but suppose 1 in 100 people has good, novel mutation. If your group has 100 people in it (per generation), then you get one good mutation. If your group has 1,000 people, then you get 10 good mutations.

Evolution isn’t like getting bitten by a radioactive spider–it can only work on the genetic variation people actually have. More genetic variation=more chances at getting a good gene that helps people survive.

Or to put it another way, we can look at a population and use “time” as one of our dimensions. Imagine a rectangle of people–all of the people in a community, over time–100 people in the first generation, 100 in the second, etc. After enough time, (10 generations or about 200 years,) you will have 1,000 people and of course hit 10 favorable mutations.

Increasing the population per generation simply increases the speed with which you get those 10 good mutations.

Interestingly:

One might think that it would take much longer for a favorable mutation to spread through such a large population than it would for one to spread through a population as small as the one that existed in the Old Stone Ag. But sine the frequency of an advantageous allele increases exponentially with time in a well-mixed population, rather like the flu, it takes only twice as long to spread through a population of 100 million as it does to spread through a population of 10,000.

The authors note that larger populations can generate more good, creative ideas, not just genes.

Agriculture–and its attendant high population densities–brought about massive cultural changes to human life, from the simple fact of sedentism (for non-pastoralists) to the ability to store crops for the winter, build long-term housing, and fund governments, which in turn created and enforced laws which further changed how humans lived and interacted. 

(Note: “government” pre-dates agriculture, but was rather different when people had no surplus grain to take as taxes.)

Agriculture also triggered the spread of plagues, as people now lived in groups large (and often squalid) enough to breed and transmit them. Related: Evidence for the Plague in Neolithic Farmers’ Teeth.

Plagues have been kind of a big deal in the history of civilization.

On government:

Combined with sedentism, these developments eventually led to the birth of governments, which limited local violence. Presumably, governments did this because it let them extract more resources from their subjects…

Peasants fighting among themselves interferes with the economy. Governments don’t like it and will tend to hang the people involved.

Some people call it self-domestication.

Recent studies have found hundreds of ongoing [genetic] sweeps–sweeps begun thousands of years ago that are still in progress today. Some alleles have gone to fixation, more have intermediate frequencies, and most are regional. Many are very recent: the rate of origination peaks at around 5,000 years ago in the European and Chinese samples, and about 8,500 years ago in the African sample.

I assume that these genes originating about 5,000 years ago are mostly capturing the Indo-European (pastoralist) and Anatolian (farming) expansions. I don’t know what happened in China around 5,000 years ago, but I wouldn’t be surprised if whatever triggered the Indo-Europeans to start moving in central Asia were connected with events further to the east.

IIRC, 8,500 years ago is too early for the Bantu expansion in Africa, so must be related to something else.

There is every reason to think that early farmers developed serious health problems from this low-protein, vitamin -short, high-carbohydrate diet. Infant mortality increased, and the poor diet was likely one of the causes. you can see the mismatch between the genes and the environment in the skeletal evidence Humans who adopted agriculture shrank: average height dropped  by almost five inches.

I have seen this claim many times, and still find it incredible. I am still open to the possibility of it having been caused by a third, underlying factor, like “more people surviving diseases that had formerly killed them.”

There are numerous signs of pathology in the bones of early agriculturalists. In the Americas, the introduction of maize led to widespread tooth decay and anemia due to iron deficiency…

Of course, over time, people adapted to their new diets. You are not a hunter-gatherer. (Probably. If you are, hello!)

…Similarly, vitamin D shortages in the new die may have driven the evolution of light skin in Europe and northern Asia. Vitamin D is produced by ultraviolet radiation from the sun acting on our skin… Since there is plenty of vitamin D in fresh meat, hunter-gatherers in Europe may not have suffered from vitamin D shortages and thus may have been able to get by with fairly dark skin. In fact, this must have been the case, since several of the major mutations causing light skin color appear to have originated after the birth of agriculture. vitamin D was not abundant in the new cereal-based diet, and any resulting shortages would have been serious, since they could lead to bone malformations (rickets,) decreased resistance to infectious diseases, and even cancer. …

I have read that of the dark-skinned peoples who have recently moved to Britain, the vegetarians among them have been the hardest-hit by vitamin D deficiency. Meat is protective. 

Peoples who have farmed since shortly after the end of the Ice Age (such as the inhabitants of the Middle East) must have adapted most thoroughly to agriculture. In areas where agriculture is younger, such as Europe or China, we’d expect to see fewer adaptive changes… In groups that had remained foragers, there would presumably be no such adaptive changes…

Populations that have never farmed or that haven’t farmed for long, such as the Australian Aborigines and many Amerindians, have characteristic health problems today when exposed to Western diets.

EG, Type 2 diabetes.

Dr. (of dentistry) Weston Price has an interesting book, Nutrition and Physical Degeneration, that describes people Price met around the world, their dental health, and their relationship to Western or traditional diets. (Written/published back in the 1930s.) I’m a fan of the book; I am not a fan of the kind of weird organization that publishes it. That organization promotes fringe stuff like drinking raw milk, but as far as I can recall, I didn’t see anything about drinking raw milk in the entirety of Dr. Price’s tome; Dr. Price wasn’t pushing anything fringe, but found uncontroversial things like “poverty-stricken children during the Great Depression did better in school when given nutritious lunches.” Price was big on improper nutrition as the cause of tooth decay and was concerned about the effects of industrialization and Western diets on people’s bones and teeth.

So we’ve reached the end of Chapter 3. What did you think? Do you agree with Greg and Henry’s model of how Type 2 Diabetes arises, or with the “thrifty genotype” promulgated by James Neel? And why do metabolic syndromes seem to affect poor whites more than affluent ones?

What about the higher rates of FAS among African Americans than the French (despite the French love of alcohol) or the straight up ban on alcohol in many Islamic (ancient farming) cultures? What’s going on there?

And any other thoughts you want to add.

See you next Wednesday for chapter 4.

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