Frederick
Morgan – Off for the Honeymoon (Wikicommons) Over the past 2,000 years, the
British gene pool has shifted toward alleles that favor lighter hair, sunburn,
and educational attainment. Was this because high-status men tended to mate
with blonder, fairer women?
Have
we evolved over the past two thousand years? Until recently, the answer was thought
to be 'no.' Cultural evolution took over from genetic evolution around the time
farming took over from hunting and gathering, some ten thousand years ago, thus
putting our ancestors on a path to increasing social complexity: sedentary
living, growth of towns and villages, formation of states, trade and
specialization of labor, and so on. It was culture that changed during recorded
history, not genes.
Well,
things are not that simple. Genes and culture have coevolved with each other.
Yes, culture has been changing rapidly over the past ten thousand years. But so
have genes. During that time, our genetic evolution has been driven by adaptation
not only to natural environments but also to cultural environments. Increasingly
so. We live more and more in cultural environments of our making (Chen et al.,
2016; Cochran and Harpending 2009; Hawks et al. 2007).
In
what ways have we changed genetically during the past ten thousand years? In
the ways we digest food. With the shift to dairy farming, and the resulting
increase in milk consumption by adults, natural selection favored those who could
digest milk sugar, an ability previously confined to infants.
We
have also changed in the ways we think and behave. That kind of evolution is
not difficult. A few point mutations may alter a behavior by changing its
timing, its intensity, or its threshold of stimulation. Other alterations have
been much more polygenic. Cognitive ability, for instance, seems to have
increased through mutations at many genes, with each mutation causing only a tiny
fraction of the increase.
Because
recent evolutionary change has so often been polygenic, we need to examine it in
relation to many genetic variants spread over the entire genome, i.e., by means
of genome-wide association studies. Such studies can take many forms. A recent
one, proposed by Stern et al. (2020), may be better than earlier versions,
particularly in avoiding biases due to population structure and population
stratification.
I
nonetheless have a few reservation about this proposed method:
1.
Population stratification can be a factor in evolutionary change. Let's take the
work of Gregory Clark on the growth of the English middle class. He found it
grew steadily from the twelfth century onward, its descendants not only growing
in number but also replacing the lower classes through downward mobility. By
the 1800s its lineages accounted for most of the English population. Parallel
to that demographic growth, English society became more and more middle class
in its values. "Thrift, prudence, negotiation, and hard work were becoming
values for communities that previously had been spendthrift, impulsive,
violent, and leisure loving" (Clark 2007, p. 166). Isn't that evolutionary
change through population stratification? Or am I missing something?
2.
The new method can reveal only evidence of directional selection. It thus fails
to capture other interesting forms of selection, like diversifying selection.
How the British have
evolved over the past 2,000 years
Stern
et al. (2020) used their method to study how the British population has evolved
over the past two thousand years. They found increases in the prevalence of lighter
hair, in tanning and sunburn, in age at first birth, in bone mineral density,
and in the risk of type 2 diabetes. They also found decreases in the risk of neuroticism
and in the risk of high glycated hemoglobin levels.
Some
of these changes correlate with each other. In such cases, we should step back
and try to identify the common cause.
Lighter hair, more
sunburn ... and higher educational attainment
Over
the past 2,000 years, the British gene pool has shifted toward alleles that
favor lighter hair, sunburn, and educational attainment. These changes in
allele frequency correlate with each other, so what, exactly, was driving the overall
change?
There
is genetic linkage between light hair and pale skin, but it's weak. In fact, pale
skin often coexists with dark hair. Moreover, we still have to explain the link
to educational attainment. The common cause for all three changes may have been
sexual selection mediated by social class. In other words, high-status men
tended to mate with blonder, fairer women.
This
form of sexual selection was observed in a Japanese study on social class and
skin color. Upper-class men were shown to be fairer-skinned than lower-class
men, even when the latter were factory workers and not farmers and even though
the measurements were taken on unexposed skin. Wealthier men have a wider range
of prospective brides and can thus choose the fairest women, for "skin
color has long been regarded, by the Japanese, as one of the criteria for
evaluating physical attractiveness, especially in young females" (Hulse
1967). Similarly, in India "[w]ealthy landowning families often have a
tradition of seeking light-skinned brides among poorer members of their
subcaste. It is very common to find a high concentration of lighter-skinned
people among established land-owning families" (Béteille 1967).
Darwin
discussed this sexual selection with reference to English social classes:
Many persons are convinced, as it appears to me with justice, that our aristocracy, including under this term all wealthy families in which primogeniture has long prevailed, from having chosen during many generations from all classes the more beautiful women as their wives, have become handsomer, according to the European standard, than the middle classes; yet the middle classes are placed under equally favorable conditions of life for the perfect development of the body. (Darwin 1936[1888], p. 892)
Until
the 20th century, higher social status meant higher fertility (Clark 2007). Thus, the
physical and mental characteristics of the upper and middle classes tended to
displace those of the lower class.
Higher risk of Type
2 diabetes and glycated hemoglobin
Why
would natural selection favor type 2 diabetes? Isn't diabetes harmful? It is,
in a modern environment that lets you ingest calories almost without limit.
That wasn't the case in Britain for most of the past two thousand years. During
that time, food was scarce for most people, and natural selection favored the
ability to get as many calories as possible out of our food.
Less neuroticism
This
evolutionary change may be related to the demographic success of the middle
class and associated mental and behavioral traits, particularly lower time
preference and higher future orientation. The nascent English middle class
valued being “calm, cool, and collected,” as opposed to reacting emotionally to
negative outcomes.
References
Béteille,
A. (1967). Race and descent as social categories in India. Daedalus 96(2): 444-463.
Chen,
C., R.K. Moyzis, X. Lei, C. Chen, and Q. Dong. (2016). The encultured genome:
Molecular evidence for recent divergent evolution in human neurotransmitter
genes. In: J.Y. Chiao, S.-C. Li, R. Seligman, and R. Turner, Eds, The Oxford handbook of cultural neuroscience.
New York, NY: Oxford University Press, 315-336.
Clark,
G. (2007). A Farewell to Alms. A Brief
Economic History of the World, 1st ed.; Princeton University Press:
Princeton.
Cochran,
G., and H. Harpending. (2009). The 10,000
Year Explosion: How Civilization Accelerated Human Evolution. Basic Books.
Darwin,
C. (1936 [1888]). The Descent of Man and
Selection in relation to Sex. reprint of 2nd edition, The Modern Library,
New York: Random House.
Hawks,
J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent
acceleration of human adaptive evolution. Proceedings
of the National Academy of Sciences, 104(52), 20753-20758.
Hulse,
F.S. (1967). Selection for skin color among the Japanese. American Journal of Physical Anthropology 27(2): 143-156.
Hysi,
P.G., A.M. Valdes, F. Liu, N.A. Furlotte, D.M. Evans, V. Bataille, et al.
(2018). Genome-wide association meta-analysis of individuals of European
ancestry identifies new loci explaining a substantial fraction of hair color
variation and heritability. Nature
Genetics 50(5): 652-656.
Morgan,
M.D., E. Pairo-Castineira, K. Rawlik, O. Canela-Xandri, J. Rees, D. Sims, A.
Tenesa, and I.J. Jackson. (2018). Genome-wide study of hair colour in UK
Biobank explains most of the SNP heritability. Nature Communications 9: 5271
Neel, J. V. (1962). Diabetes mellitus:
a 'thrifty' genotype rendered detrimental by 'progress'? American Journal of Human Genetics 14: 353-362.
Stern,
A.J., L. Speidel, N.A. Zaitlen, and R. Nielsen. (2020). Disentangling selection
on genetically correlated polygenic traits using whole-genome genealogies
bioRxiv 2020.05.07.083402
23 comments:
For a long time, British civilization was at the forefront of human progress. But the things it produced -- capitalism, freedom, morality, egalitarianism, the rule of law -- sort of contained the "seeds of its own destruction" which we're unfortunately witnessing today. That "decrease in neuroticism" that you cite is directly linked to the impotence and failure to stand up to the destruction we're witnessing right now. These days people look to Russia as the savior of civilization. There is more neuroticism in Russia, but that means healthier self-preservation instincts.
Having had some kids at UK private school and some at state school, definitely more blonde mums at the private school gates. Given that tall blondes are the gold standard for successful men, that's not surprising.
Greater bone mineral density may be an adaptation for women to having many children. It takes a lot of calcium to make a baby. Blondes tend to be fair; yes, but they also incline to be tawny and easily tan rather than burn.
The Yamnaya period of invasion is when the dark skin allele disappeared from Europe, presumably the dark skin women got mated, but the Yamnaya were not interested in taking care of them. White skin elicits care and provisioning. My conclusion is that Bronze Age high-status men would have tended to mate lots of women but those given the status of official wife and thus project their DNA into subsequent generations would be have to be as white skinned as possible rather than a tanned blonde, which is the sexy gold standard.
Over the past 2,000 years, the British gene pool has shifted toward alleles that favor lighter hair but not the palest of pale skin because redheads have that. A Scottish study the other year found in addition to MC1R there are eight more genes associated with red hair. I would speculate that red hair is a side effect of extreme selection for white skin back in the Bronze age, but blonde hair and a somewhat tawny complexion has had the advantage for the last 2000 years.
"definitely more blonde mums at the private school gates"
Most British Blondes Are Fake
"tall blondes are the gold standard for successful men"
UK Survey: Brunettes Trump Blondes ... Again
British Men's Hair and Eye Color Preferences
"The Yamnaya period of invasion is when the dark skin allele disappeared from Europe"
It was Anatolian farmers who originally brought light skin alleles to Europe.
Myth of the light pigmented "Nordic looking" Proto Indo-Europeans debunked
I won't mince words, British people can be rather "robust" in appearance like Australian Aboriginals. I would expect Eastern Europeans to have undergone a large amount of sexual selection since their women are considered very attractive compared to other Europeans in other parts of the world.
Truth seeker,
Our strengths are also our weaknesses. Northwest Europeans have moved away from kinship morality and toward morality based on universal rules. This has made possible the creation of larger societies in which most social and economic interaction is no longer between close kin. That kind of society is potentially more productive and is more conducive to a market economy. But it is also vulnerable to groups who say "Universalism for thee but not for me!" WASPs take pride in their rugged individualism but they are simply no match for well organized collectivists.
Anon,
I read a skin reflectance study from France, which found that students in private schools were significantly lighter-skinned than students in public schools, even among "Français de souche." This seemed to be a result of higher-status men seeking and marrying fair-skinned wives. I tried looking for it now but to no avail :(
Sean,
"The Yamnaya period of invasion is when the dark skin allele disappeared from Europe"
I don't think so.
https://evoandproud.blogspot.com/2014/03/did-europeans-become-white-in-historic.html
"I would speculate that red hair is a side effect of extreme selection for white skin back in the Bronze age"
Ancient DNA shows that red hair was present in Scandinavia and the Baltic region long before the bronze age. It was certainly around in the Mesolithic.
Anon,
"It was Anatolian farmers who originally brought light skin alleles to Europe"
Ancient DNA shows that those alleles were present in Scandinavia and the Baltic region long before farming. Nobody brought them to Europe. They arose and were selected in Europe.
"I would expect Eastern Europeans to have undergone a large amount of sexual selection since their women are considered very attractive"
The zone of most intense sexual selection was probably on the Great European Plain (from northern France to central Siberia). This was during the last ice age, so a lot has changed demographically since then.
If we're comparing apples with apples, I wouldn't say that Eastern European women are inherently more attractive than women elsewhere in Europe. Part of that judgment is a reflection of the marriage squeeze in Western Europe. Among single people up to the age of 40, there are more men than women. This is the situation throughout the Western world, and it is only a matter of time before eastern Europe catches up (because of declining male mortality, older divorced men remarrying with younger wives, and male predominance among immigrants).
At present, a single woman in Eastern Europe is not comparable to a single woman in Western Europe. The latter are much more likely to have detractions of one sort or another.
"Truth seeker,
Our strengths are also our weaknesses. Northwest Europeans have moved away from kinship morality and toward morality based on universal rules. This has made possible the creation of larger societies in which most social and economic interaction is no longer between close kin. That kind of society is potentially more productive and is more conducive to a market economy. But it is also vulnerable to groups who say "Universalism for thee but not for me!" WASPs take pride in their rugged individualism but they are simply no match for well organized collectivists."
The interesting thing, for me, is "how is selective pressure working on WASPs?"
The WASP exposed to organized collectivists gene-meme co-evolution are surely under a selective pressure both memetic and genetic.
How are they adapting?
Who are the conservatives more damaged by leftists collectivism?
I see a increasing tendency to advocate for "reciprocity" and not "fairness".
A move to apply to others the rules them want to apply to everyone else.
Also, the organized collectivists are not very good at producing wealth and the current level of society wealth needs a very efficient & effective way to produce wealth or things collapse very fast.
"Ancient DNA shows that those alleles were present in Scandinavia and the Baltic region long before farming. Nobody brought them to Europe. They arose and were selected in Europe."
What Ancient DNA shows is that Farmers were much lighter skinned than Hunter-Gatherers, and Europeans are half farmer.
Phenotypes of Hunters and Farmers
"chinless wonders"
Peter,
I've never been to Canada, and this is completely speculative and unscientific and just based on my impression from viewing Canadian media and seeing Canadian celebrities and expats in the US, which of course isn't very representative. But is there any truth to my impression that the native English speaking Canadian phenotype tends to be very brunet compared to white Americans? The phenotype I have in mind is like that of Canadians Norm Macdonald or Mike Myers i.e. people of wholly or mostly English/British ancestry with pale skin and dark brown hair.
This phenotype of course is common among white Americans as well, but I wondered if because of greater immigration from Germanic/Scandinavian countries into the US, it was less predominant among white Americans than it seemed to be among English speaking Canadians whose ancestry was more English/British.
Painlord,
The adaptation will have to be memetic (the time-scale is too short). Yes, the collectivists are killing the goose that laid the golden egg, and I suspect that many are aware of this, but self-awareness isn't enough. Many drug addicts are fully aware of the harm they are doing to themselves and to others, but they continue on their present course because that's all they know.
It's necessary to articulate and put forward alternatives. I understand that's not easy, especially in the current climate. But it will never be easy.
Anon,
You're assuming that all European hunter-gatherers were the same. Yes, the hunter-gatherers of western and central Europe were dark-skinned, but those of Scandinavia and the Baltic region were already fair-skinned.
Günther, T., H. Malmström, E.M. Svensson, A. Omrak, F. Sánchez-Quinto, G.M. Kilinç, et al. (2018). Population genomics of Mesolithic Scandinavia: Investigating early postglacial migration routes and high-latitude adaptation. PLoS Biol 16(1): e2003703. https://doi.org/10.1371/journal.pbio.2003703
Mittnik, A., C-C. Wang, S. Pfrengle, M. Daubaras, G. Zarina, F. Hallgren, et al. (2018). The genetic prehistory of the Baltic Sea region. Nature Communications 9(442)
https://doi.org/10.1038/s41467-018-02825-9
The very first farmers in Europe were actually dark-skinned.
https://evoandproud.blogspot.com/2015/08/the-past-is-another-country.html
Anon,
That seems to be the stereotype. "Old Stock" English Canadians were mostly Loyalists or "Late Loyalists" from the U.S., but there were also large numbers of immigrants from the British Isles. My mother's family came from London in the late 19th century. My father was actually born in England. At my school, about a quarter of the kids were blond, so I wouldn't say that blond hair was unusual.
"Old Stock" Americans seem to be disproportionately of German origin or descended from religious dissidents who came from the East of England. That might explain a greater tendency toward blond hair.
Peter,
Thanks. Very interesting. So I wasn't off in my impression.
Mike Myers was born in Canada but his parents had moved from England. Rachel McAdams, a Hollywood actress, was another Canadian celebrity I had in mind. Her hair is usually dyed blonde or lightened, but her natural hair is dark brown. According to Wiki, her ancestry is wholly British, and her ancestors include a Loyalist Ranger who fled to Canada during the Revolution.
I assumed the difference in general phenotype was due to Old Stock English speaking Canadians being of purer British type and ancestry compared to Old Stock Americans having continental Germanic admixture. The greater Puritan element from the East of England in the US relative to Canada would make sense too.
I'd like to echo what Anonymous said about the Anglo genotype being surprisingly dark-haired. Mitt Romney, for example, the Beatles, the Rolling Stones, or the British comedian "Mr. Bean" all exemplify the dark-haired Anglo look. It seems to be common and very different from the Germanic and Slavic lighter hair.
Truth Seeker,
I don't think the dark haired phenotype I've been talking about characterizes the English/Brits in general. Rather it seems to be a major subtype among others that are common but quite different e.g. blond, redheaded, "red nordid", etc.
What I was talking about was how it seemed to me that English Canadians in particular seemed to be drawn from this subtype.
1. Isn't it that a plant-based diet makes you paler? The more plant-based the paler - up to the dead-pale for vegans? And within those 2 thousand years the diet became more and more plant-bases? If so the genes would only adapt people to the bad situation they are in anyway - too little meat in the diet? I mean if there was no chance to be dark like a human should because of the diet available for thousands of years, then genes that made one at least well adopted to be white would win out?
Examples of plant based diet changing eye color to lighter, from Vegan Phobic channel:
https://www.youtube.com/watch?v=i1DJHUpad3M
Anti Vegan and Vegan Deterioration have lots of examples of vegans deteriorating, and as you can see most of them get paler on a plant based diet. Notice the described degeneration also icludes face narrowing. Eg.
https://www.youtube.com/watch?v=NLT87fXrJ18
https://www.youtube.com/watch?v=oBKhMdF_6Ps
https://www.youtube.com/watch?v=XkB7S-5CHus
https://www.youtube.com/watch?v=jQg8qalf9ec
The people who survive on a plant based diet are thus the ones that have pale skin in the first place, and a narrow face also? People looking like this:
https://www.youtube.com/watch?v=cA896H1P9ZU
While at the same time old-shool hunter-gatherers would be people with wide faces
2. Dark hair is suposed to accent the features of the face. So if a woman has a beautiful face she is going to be looking better with dark hair. British women getting lighter hair with time may as well be an evolutionary advantage for non-attractive faces?
"The very first farmers in Europe were actually dark-skinned."
Your source is an article in Greek that mentions only 3 samples and doesn't give any details. Published Ancient DNA shows that Neolithic Farmers had light skin. Even the Gunther paper you just posted shows that, and it says the alleles arose in the Middle East and came to Europe (including Scandinavia/Baltic) from there:
"The large effect light-skin alleles at rs16891982 and rs1426654 were present in SHG, EHG, CHG and EEF but absent in WHG and PEHG. Similarly, the C11 haplotype is present in hunter-gatherers (SHG, EHG and CHG but not WHG and PEHG) throughout Europe, as well as in at least two early farmers. This pattern is consistent with reports that the rs1426654 derived allele arose ~22,000-28,000 years ago (186, 187), and that the light-pigmentation allele at rs16891982 arose only once in Eurasians (186, 188). A possible geographical origin for these two major light-skin alleles is West Asia or the Near East (189). Later migrations across the Caucasus (CHG) and Eastern Europe would have brought it to Scandinavia, while EEF migrations introduced both alleles into central Europe."
The Canadian phenotype I referred to in comments above apparently was/is a recognized type of the British Isles called "Atlantid" in traditional physical anthropology:
https://en.wikipedia.org/wiki/Atlantid_race
White Americans are mostly English-German-Irish. Compared to that, white Canadians are mostly English-French-Scottish-Irish. Canadians have more Scottish and French blood, but less German blood, although German Canadian ancestry definitely exists.
USA, 1980 census, last accurate Euro ancestry data (without the new "American" category): https://www.census.gov/population/censusdata/pc80-s1-10/tab02.pdf
Top groups: English=26.34%, German=26.14%, Irish=21.33%.
Smaller groups: French=6.85%, Italian=6.47%, Scottish=5.34%, Polish=4.37%.
Scandinavians are at 2-3%. Swedish=2.31%, Norwegian=1.83%.
Canada: there's recent data on Wikipedia, but it includes "Canadian" which is misleading, but nonetheless, taking the 2006 census: https://en.wikipedia.org/wiki/European_Canadians
Top groups: English=21%, French=15.82%, Scottish=15.11%, Irish=13.94%, German=10.18%
Smaller groups: Italian=4.63%, Ukrainian=3.87%, Dutch=3.32%, Polish=3.15%
Anon,
According to aDNA, light skin was already present in Scandinavia 9500 years ago, when agriculture was just starting to develop in the Middle East. At that time, Europeans were still hunter-gatherers. We have no evidence of light skin among those early Middle Eastern farmers. (Remember, we're talking 9500 BP). To make your model work, you would have to make a number of unrealistic assumptions.
According to Gunther, most light skin alleles were introduced to Europe by Neolithic farmers. Some may have reached Scandinavia a little earlier but they were still the same West Asian alleles. They didn't originate in European hunter-gatherers, who had dark skin.
“ According to Gunther, most light skin alleles were introduced to Europe by Neolithic farmers. Some may have reached Scandinavia a little earlier but they were still the same West Asian alleles. They didn't originate in European hunter-gatherers, who had dark skin.”
That’s not true. There was no neolithic presence anywhere in Scandinavia until 4000BC with the arrival of the funnelbeaker culture. And there is also the question of baltic hunters from both the kunda and narva cultures that also did not posses any Neolithic anatolian ancestry yet still possessed light skin alleles. Only western euro hunter gatherers were dark, eastern ones were found to be light skinned, despite being mixed with the former.
@Peter
"At present, a single woman in Eastern Europe is not comparable to a single woman in Western Europe. The latter are much more likely to have detractions of one sort or another."
Eastern Europe has kept a higher ratio of women to men.
If the male to female ratio has changed in western Europe, it could explain the difference. I can believe quality has gone down.
Post a Comment