The spread of the lactose-tolerant gene seems to coincide with the beginning of civilization:
“I've probably worked more on the evolution of lactose tolerance than anyone in the world,” says Thomas. “I can give you a bunch of informed and sensible suggestions about why it's such an advantage, but we just don't know. It's a ridiculously high selection differential, just insane, for the last several thousand years.”The Most Spectacular Mutation in Recent Human History (Slate)
A “high selection differential” is something of a Darwinian euphemism. It means that those who couldn't drink milk were apt to die before they could reproduce. At best they were having fewer, sicklier children. That kind of life-or-death selection differential seems necessary to explain the speed with which the mutation swept across Eurasia and spread even faster in Africa. The unfit must have been taking their lactose-intolerant genomes to the grave.
Milk, by itself, somehow saved lives. This is odd, because milk is just food, just one source of nutrients and calories among many others. It's not medicine. But there was a time in human history when our diet and environment conspired to create conditions that mimicked those of a disease epidemic. Milk, in such circumstances, may well have performed the function of a life-saving drug.
There are no written records from the period when humans invented agriculture, but if there were, they would tell a tale of woe. Agriculture, in Jared Diamond's phrase, was the “worst mistake in human history.” The previous system of nourishment—hunting and gathering—had all but guaranteed a healthy diet, as it was defined by variety. But it made us a rootless species of nomads. Agriculture offered stability. It also transformed nature into a machine for cranking out human beings, though there was a cost. Once humans began to rely on the few crops that we knew how to grow reliably, our collective health collapsed. The remains of the first Neolithic farmers show clear signs of dramatic tooth decay, anemia, and low bone-density. Average height dropped by about 5 inches, while infant mortality rose. Diseases of deficiency like scurvy, rickets, beriberi, and pellagra were serious problems that would have been totally perplexing. We are still reeling from the change: Heart disease, diabetes, alcoholism, celiac disease, and perhaps even acne are direct results of the switch to agriculture.
Meanwhile, agriculture's alter ego, civilization, was forcing people for the first time to live in cities, which were perfect environments for the rapid spread of infectious disease. No one living through these tribulations would have had any idea that things had ever been, or could be, different. Pestilence was the water we swam in for millennia.
It was in these horrendous conditions that the lactose tolerance mutation took hold. Reconstructed migration patterns make it clear that the wave of lactose tolerance that washed over Eurasia was carried by later generations of farmers who were healthier than their milk-abstaining neighbors. Everywhere that agriculture and civilization went, lactose tolerance came along. Agriculture-plus-dairying became the backbone of Western civilization.
But it's hard to know with any kind of certainty why milk was so beneficial. It may have been the case that milk provided nutrients that weren't present in the first wave of domesticated crops. An early, probably incorrect, hypothesis sought to link lactose tolerance to vitamin D and calcium deficiencies. The lactose-intolerant MIT geneticist Pardis Sabeti believes that milk boosted women's fat stores and thus their fertility, contributing directly to Darwinian fitness, though she and others allow that milk's highest value to subsisting Homo sapiens may have been that it provided fresh drinking water: A stream or pond might look clean yet harbor dangerous pathogens, while the milk coming out of a healthy-looking goat is likely to be healthy, too.
Each of these hypotheses makes rough-and-ready sense, but not even their creators find them totally convincing. “The drinking-water argument works in Africa, but not so much in Europe,” says Thomas. He favors the idea that milk supplemented food supplies. “If your crops failed and you couldn't drink milk, you were dead,” he says. “But none of the explanations that are out there are sufficient.”
The plot is still fuzzy, but we know a few things: The rise of civilization coincided with a strange twist in our evolutionary history. We became, in the coinage of one paleoanthropologist, “mampires” who feed on the fluids of other animals. Western civilization, which is twinned with agriculture, seems to have required milk to begin functioning. No one can say why. We know much less than we think about why we eat what we do. The puzzle is not merely academic. If we knew more, we might learn something about why our relationship to food can be so strange.
For the time being, the mythical version of the story isn't so bad. In the Garden, Adam and Eve were gatherers, collecting fruits as they fell from the tree. Cain the farmer and Abel the pastoralist represented two paths into the future: agriculture and civilization versus animal husbandry and nomadism. Cain offered God his cultivated fruits and vegetables, Abel an animal sacrifice that Flavius Josephus tells us was milk. Agriculture, in its earliest form, brought disease, deformation, and death, so God rejected it for the milk from Abel's flocks. Cain grew enraged and, being your prototypically amoral city-dweller, did his brother in. God cursed Cain with exile, commanding him to wander the earth like the pastoralist brother he'd killed. Cain and agriculture ultimately won the day—humans settled into cities sustained by farms—but only by becoming a little like Abel. And civilization moved forward.
It moved forward did it? Read that last paragraph again - civilization stared with murder, and it's been so ever since. Folk memory perhaps? Then reread paragraphs 4 and 5, with reference to Jared Diamond's essay. It's a good summary of the view now almost universally shared by anthropologists - and a complete inverse of the views formerly held - that agriculture was a great leap forward because we never had to worry about food shortages. By contrast, it increased population such that we always had to worry about food shortages, and we had far less variety and inferior quality of food than before. In addition to communicable disease, cavities, anemia, famine and protein deficiency, storable surpluses also led to indebtedness, private ownership, patriarchy, slavery, and war (grain could feed armies on long campaigns rather than just tribal skirmishes). As I posted a while back from this BBC article on the world's oldest writing:
Even without knowing all the symbols, Dr Dahl says it's possible to work out the context of many of the messages on these tablets. The numbering system is also understood, making it possible to see that much of this information is about accounts of the ownership and yields from land and people. They are about property and status, not poetry.Of course, this is the best evidence of my theory that something else happened about 10,000 years ago that made civilization possible - the emergence of the authoritarian personality, possibly linked to the development of "organized" religion. Once this "gene" became dominant like the lactose gene, civilization would be possible due to people willingly submitting to and working on behalf of their "betters" who now "owned" everything. Command-and-control societies would have had a huge advantage in warfare over individualistic societies, ones where people did not accept the authority of a "leader" or obey his every whim because of some commitment to a god or nation. Such people were wiped out, the thinking goes, and authoritarians bred with the women passing along their genes. By accident I ran across this post, which gets at pretty much a similar idea:
This was a simple agricultural society, with a ruling household. Below them was a tier of powerful middle-ranking figures and further below were the majority of workers, who were treated like "cattle with names". Their rulers have titles or names which reflect this status - the equivalent of being called "Mr One Hundred", he says - to show the number of people below him.
It's possible to work out the rations given to these farm labourers. Dr Dahl says they had a diet of barley, which might have been crushed into a form of porridge, and they drank weak beer. The amount of food received by these farm workers hovered barely above the starvation level.
However the higher status people might have enjoyed yoghurt, cheese and honey. They also kept goats, sheep and cattle. For the "upper echelons, life expectancy for some might have been as long as now", he says. For the poor, he says it might have been as low as in today's poorest countries.
In his book, The Third Chimpanzee, Pulitzer Prize winning author Jared Diamond explains how the earliest Europeans owed their success to their continent’s domesticatable animals. As Dr. Diamond explains, of the hundreds of potential candidates, only a small number of animals are capable of being domesticated.
Domestication, as opposed to taming, requires a short list of unimpressive traits. In addition to living in herds, the animals must breed in captivity. They can’t be high-strung. And they must be innately submissive towards dominant members of their own species. Most importantly, their submissiveness must be transferable to human handlers.Rudolph the Brown-Nose Hominid: Were Homo Sapiens Bred to Be Submissive? (The Dopamine Project)
It’s a complicated mix. Reindeer are only one out of over forty deer species that have been domesticated. Five of the eight horse species have never been broken. Camels can be domesticated but their cousins, the vicuna, can’t. Most species of sheep refuse to behave like ‘sheep.’ And except for cats and ferrets no other solitary territorial species have succumbed.
Professor Diamond’s book doesn’t contain any mention about Homo sapiens being prime candidates for domestication. His omission seems strange, especially since Homo sapiens’ undeniable submissiveness and herding instincts, coupled with a strong aversion to independent thinking, provides so many insights into how unconscious war mongers managed to cripple our species’ fate.
Diamond’s oversight raises an interesting question: What if there were more than a few, or dozens of, hominid species in addition to Homo neanderthalis and Homo sapiens? And what if the hominids who couldn’t be domesticated, including Homo neanderthalis, were simply slaughtered by vengeful control freaks who destroyed their indomitable male counterparts, impregnated the females, and eliminated irrepressible offspring?
Primatologist Frans de Waal noted, “Nevertheless, it cannot be coincidental that the only animals in which gangs of males expand their territory by deliberately exterminating neighboring males happen to be humans and chimpanzees.”
Homo sapiens and chimpanzee males, who are also known to practice infanticide, murder neighboring males to get at the females. Knowing what we know, it seems more than possible that we are descendents of Homo Rudolphis.
The primitive gangsters responsible for the artificial selection of our species didn’t have to be rocket scientists. Derailing evolution was as easy as following the dopamine-influenced instincts that kept them ingesting the foods that turned them on and swatting the mosquitoes that turned them off. The foods that turned them on were the edibles that turned on the dopamine flow. Mosquitoes turned them off because mosquito bites turned the dopamine flow off.
For millennia, acquiescent minions were permitted to live and reproduce, as long as they did their part to keep the bosses’ dopamine flowing. Throughout history, the most brutish minions earned their keep by swatting annoying questioners and other threats to the bosses’ dopamine flow. Genetics took care of the details.
Once you have an authoritarian class that will obey the leader and twist their thinking around to believe whatever power justifications and reasons for war that are given (authoritarianism is characterized by compartmentalized thinking and bottomless self-rationalization [example]), you can be the head of a civilization, and enslave people. So the conquest theory for lactose tolerance (that it was spread by conquering peoples, probably proto-Indo-Europeans) works doubly well for this, in fact it requires it. As above, the people who are submissive (sheeple) are allowed to breed, while those who resist (anti-authoritarians) are slaughtered. In fact, authoritarianism is linked with a desire to breed, as evidenced by the obsession with babies and families by the Christian right (I see cheesy billboards with babies from Pro-Life America on my way home from work, and I also saw a Christian bookstore monikered "Family" out in the burbs). It also explains the justification for rape and incest and the forbidding of all birth control by far right (invariably Republican) religious groups in America. Authoritarianism and reproductive success are linked, and probably have been for a long, long time.
As this commenter put it: "If your tribe doesn’t drink milk, you are killed or enslaved by the more numerous warriors of the neighboring tribe that does. If your tribe does drink milk, you gain reproductive access to the enslaved women of the neighboring non-milk-drinking tribe. Sounds like a basis for extremely rapid genetic success, though it would require more study of early agricultural yields to pin down with real confidence." Remember, as with lactose tolerance, you don't expect everyone to have it, just enough to achieve your objective. Then the authoritarians will keep the non authoritarians in line. Perhaps you recall the scene from the original Conan The Barbarian film (written by Oliver Stone and John Milius) where Thulsa Doom answers the "Riddle of Steel." His point was, no matter how strong your arm or how able you are with a sword, you will be defeated by numbers. Thus it is much more powerful to have control over the hearts and minds of others than to be the greatest single warrior in history.