Here are the numbers I’ve found so far for Neanderthal and Denisovan DNA in different populations:
Sriram Sankararaman et al, in The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans, 2016, report:
Native Americans: 1.37%
Central Asia: 1.4%
East Asia: 1.39%
Oceana (Melanesians): 1.54%
South Asia: 1.19%
(I have seen it claimed that the high Neanderthal percents for Oceanan populations (that is, Melanesians and their relatives,) could be a result of Denisovan DNA being incompletely distinguished from Neanderthal.)
Prufer et al, [pdf] 2017, report somewhat higher values:
East Asians: 2.3–2.6%
While Lohse and Frantz estimate an even higher rate of between 3.4–7.3% for Europeans and East Asians. (They found 5.9% in their Chinese sample and 5.3% in their European.)
The Mixe and Karitiana people of Brazil have 0.2% Denisovan (source); other estimates for the amount of Denisovan DNA in Native populations are much lower–ie, 0.05%.
I found an older paper by Prufer et al with estimates for three Hispanic populations, but doesn’t clarify if they have Native American ancestry:
Neandertal ancestry (%)
CEU–Euros from Utah
CHB–Han Chinese Beijing
CHS–Han Chinese South
CLM: Colombians from Medellin
MXL: Mexicans from LA
PUR: Puerto Ricans
LWK: Luhya in Webuye, Kenya
ASW: African Americans South West US
Since the paper is older, all of its estimates are lower than current estimates, because we now have more Neanderthal DNA to compare against. However, you can still see the general trend.
The difference between “autosomes” and “X” highlighted here is that (IIRC) autosomes includes all chromosomes except the XY pair, and X is the X from that pair. They’re breaking them up this way because the X chromosome tends to have very little Neanderthal on it (and the Y even less), probably because Neanderthal DNA on these particular chromosomes was selected against.
Neanderthal DNA appears to have been selected for in areas that control hair and skin–people who had just left Africa were adapted to the African environment, and Neanderthal hair and skin traits helped them survive in colder, darker winters. We also see a lot of Neanderthal DNA influencing inflammation/immune response–these may have helped people fend off new diseases. But we see almost no Neanderthal (or Denisovan) DNA in areas of the genome that code for sperm, eggs, testes, ovaries, etc. These parts of people were probably already finely tuned to work together, didn’t need to change with the environment, and changing anything probably just made them less efficient–so Neanderthal (and Denisovan) DNA on the X and Y chromosomes has been purged from the Homo Sapiens gene pool.
Algeria 44.57% = 0.52% Neanderthal
Tunisia 100.16% = 1.172 N
Tunisia 138.13% = 1.6% N (This is an interesting population that has been highly endogamous and thus better reflects historical populations in the area.)
Egypt 58.45% = 0.68% N
Libya 56.36% = 0.66% N
Morroco North 69.17% = 0.81% N
Morocco South 17.90% = 0.21% N
Saharawi 50.90% = 0.6% N
Canary Island* 101.44% = 1.187% N
China Beijing 193.43% = 2.26 % N
China 195.41% = 2.29% N
Texas Indu Gupti 84.37% =0.987% N
Andalusia*118.66% = 1.39% N
Tuscan 94.90% = 1.11% N
Basque BASC 129.48% = 1.51% N
Galicia* GAL 115.86% = 1.36% N
Yoruba YRI 0.00% = 0% N
Luyha LWK −14.89% = N
The authors note that they are not sure how the Luyha received a negative score–perhaps the presence of admixed DNA from yet another species is interfering with the results.
Denisovan DNA is most commonly found in Melanesians, Papulans, Aboriginal Australians and Aboriginal Filipinos, who all have similar amounts around 4-6%, indicating that they probably were all one group when their ancestors met the Denisovans. However, the similar-looking but historically quite isolated Onge people have no Denisovan–so they split off before the event.
In Papuans, Neanderthal DNA tends to be expressed in brain tissue, Denisovan in bones and other tissues.
Asians have a small amount of Denisovan DNA; Tibetans have a particular gene that lets them absorb oxygen effectively at high altitudes that they got from the Denisovans.
The Mende People of Sierra Leon may derive 13% of their DNA from an as-yet unknown hominin species (ancient DNA and bones do not preserve well in parts of Africa, so finding remains and identifying the species may be difficult.)
The Yoruba derive 8 or 9% of their DNA from the same hominin.
Masai have a small fraction of Neanderthal–since they are 30% non-African, probably about 0.35% of their genome–but you can read the paper yourself.
Biaka Pygmies and Bushmen (San): 2% from an unknown archaic.
With more testing, better and more comprehensive numbers are sure to turn up.
In previous posts, we discussed the evolution of Whites and Asians, so today we’re taking a look at people from Sub-Saharan Africa.
Modern humans only left Africa about 100,000 to 70,000 yeas ago, and split into Asians and Caucasians around 40,000 years ago. Their modern appearances came later–white skin, light hair and light eyes, for example, only evolved in the past 20,000 and possibly within the past 10,000 years.
What about the Africans, or specifically, Sub-Saharans? (North Africans, like Tunisians and Moroccans, are in the Caucasian clade.) When did their phenotypes evolve?
The Sahara, an enormous desert about the size of the United States, is one of the world’s biggest, most ancient barriers to human travel. The genetic split between SSAs and non-SSAs, therefore, is one of the oldest and most substantial among human populations. But there are even older splits within Africa–some of the ancestors of today’s Pygmies and Bushmen may have split off from other Africans 200,000-300,000 years ago. We’re not sure, because the study of archaic African DNA is still in its infancy.
The Bushmen present an interesting case, because their skin is quite light (for Africans.) I prefer to call it golden. The nearby Damara of Namibia, by contrast, are one of the world’s darkest peoples. (The peoples of South Sudan, eg Malik Agar, may be darker, though.) The Pygmies are the world’s shortest peoples; the peoples of South Sudan, such as the Dinka and Shiluk, are among the world’s tallest.
Sub-Saharan Africa’s ethnic groups can be grouped, very broadly, into Bushmen, Pygmies, Bantus (aka Niger-Congo), Nilotics, and Afro-Asiatics. Bushmen and Pygmies are extremely small groups, while Bantus dominate the continent–about 85% of Sub Saharan Africans speak a language from the Niger-Congo family. The Afro-Asiatic groups, as their name implies, have had extensive contact with North Africa and the Middle East.
Most of America’s black population hails from West Africa–that is, the primarily Bantu region. The Bantus and similar-looking groups among the Nilotics and Afro-Asiatics (like the Hausa) are, therefore, have both Africa’s most iconic and most common phenotypes.
For the sake of this post, we are not interested in the evolution of traits common to all humans, such as bipedalism. We are only interested in those traits generally shared by most Sub-Saharans and generally not shared by people outside of Africa.
One striking trait is black hair: it is distinctively “curly” or “frizzy.” Chimps and gorrilas do not have curly hair. Neither do whites and Asians. (Whites and Asians, therefore, more closely resemble chimps in this regard.) Only Africans and a smattering of other equatorial peoples like Melanesians have frizzy hair.
Black skin is similarly distinct. Chimps, who live in the shaded forest and have fur, do not have high levels of melanin all over their bodies. While chimps naturally vary in skin tone, an unfortunate, hairless chimp is practically “white.”
Humans therefore probably evolved both black skin and frizzy hair at about the same time–when we came out of the shady forests and began running around on the much sunnier savannahs. Frizzy hair seems well-adapted to cooling–by standing on end, it lets air flow between the follicles–and of course melanin is protective from the sun’s rays. (And apparently, many of the lighter-skinned Bushmen suffer from skin cancer.)
Steatopygia also comes to mind, though I don’t know if anyone has studied its origins.
According to Wikipedia, additional traits common to Sub-Saharan Africans include:
Modern cross-analysis of osteological variables and genome-wide SNPs has identified specific genes, which control this craniofacial development. Of these genes, DCHS2, RUNX2, GLI3, PAX1 and PAX3 were found to determine nasal morphology, whereas EDAR impacts chin protrusion. …
Ashley Montagu lists “neotenous structural traits in which…Negroids [generally] differ from Caucasoids… flattish nose, flat root of the nose, narrower ears, narrower joints, frontal skull eminences, later closure of premaxillarysutures, less hairy, longer eyelashes, [and] cruciform pattern of second and third molars.”
As hominids gradually lost their fur (between 4.5 and 2 million years ago) to allow for better cooling through sweating, their naked and lightly pigmented skin was exposed to sunlight. In the tropics, natural selection favoured dark-skinned human populations as high levels of skin pigmentation protected against the harmful effects of sunlight. Indigenous populations’ skin reflectance (the amount of sunlight the skin reflects) and the actual UV radiation in a particular geographic area is highly correlated, which supports this idea. Genetic evidence also supports this notion, demonstrating that around 1.2 million years ago there was a strong evolutionary pressure which acted on the development of dark skin pigmentation in early members of the genus Homo.…
About 7 million years ago human and chimpanzee lineages diverged, and between 4.5 and 2 million years ago early humans moved out of rainforests to the savannas of East Africa. They not only had to cope with more intense sunlight but had to develop a better cooling system. …
Skin colour is a polygenic trait, which means that several different genes are involved in determining a specific phenotype. …
Data collected from studies on MC1R gene has shown that there is a lack of diversity in dark-skinned African samples in the allele of the gene compared to non-African populations. This is remarkable given that the number of polymorphisms for almost all genes in the human gene pool is greater in African samples than in any other geographic region. So, while the MC1Rf gene does not significantly contribute to variation in skin colour around the world, the allele found in high levels in African populations probably protects against UV radiation and was probably important in the evolution of dark skin.
Skin colour seems to vary mostly due to variations in a number of genes of large effect as well as several other genes of small effect (TYR, TYRP1, OCA2, SLC45A2, SLC24A5, MC1R, KITLG and SLC24A4). This does not take into account the effects of epistasis, which would probably increase the number of related genes.Variations in the SLC24A5 gene account for 20–25% of the variation between dark and light skinned populations of Africa, and appear to have arisen as recently as within the last 10,000 years. The Ala111Thr or rs1426654 polymorphism in the coding region of the SLC24A5 gene reaches fixation in Europe, and is also common among populations in North Africa, the Horn of Africa, West Asia, Central Asia and South Asia.
That’s rather interesting about MC1R. It could imply that the difference in skin tone between SSAs and non-SSAs is due to active selection in Blacks for dark skin and relaxed selection in non-Blacks, rather than active selection for light skin in non-Blacks.
MC1R is one of the key proteins involved in regulating mammalianskin and hair color. …It works by controlling the type of melanin being produced, and its activation causes the melanocyte to switch from generating the yellow or red phaeomelanin by default to the brown or black eumelanin in replacement. …
This is consistent with active selection being necessary to produce dark skin, and relaxed selection producing lighter tones.
Studies show the MC1R Arg163Gln allele has a high frequency in East Asia and may be part of the evolution of light skin in East Asian populations. No evidence is known for positive selection of MC1R alleles in Europe and there is no evidence of an association between MC1R and the evolution of light skin in European populations. The lightening of skin color in Europeans and East Asians is an example of convergent evolution.
Dark-skinned people living in low sunlight environments have been recorded to be very susceptible to vitamin D deficiency due to reduced vitamin D synthesis. A dark-skinned person requires about six times as much UVB than lightly pigmented persons.
In Reconstructing Prehistoric African Population Structure, Skoglund et al assembled genetic data from 16 prehistoric Africans and compared them to DNA from nearby present-day Africans. They found:
The ancestors of the Bushmen (aka the San/KhoiSan) once occupied a much wider area.
They contributed about 2/3s of the ancestry of ancient Malawi hunter-gatherers (around 8,100-2,500 YA)
Contributed about 1/3 of the ancestry of ancient Tanzanian hunter-gatherers (around 1,400 YA)
Farmers (Bantus) spread from west Africa, completely replacing hunter-gatherers in some areas
Modern Malawians are almost entirely Bantu.
A Tanzanian pastoralist population from 3,100 YA spread out across east Africa and into southern Africa
Bushmen ancestry was not found in modern Hadza, even though they are hunter-gatherers and speak a click language like the Bushmen.
The Hadza more likely derive most of their ancestry from ancient Ethiopians
Modern Bantu-speakers in Kenya derive from a mix between western Africans and Nilotics around 800-400 years ago.
Middle Eastern (Levant) ancestry is found across eastern Africa from an admixture event that occurred around 3,000 YA, or around the same time as the Bronze Age Collapse.
A small amount of Iranian DNA arrived more recently in the Horn of Africa
Ancient Bushmen were more closely related to modern eastern Africans like the Dinka (Nilotics) and Hadza than to modern west Africans (Bantus),
This suggests either complex relationships between the groups or that some Bantus may have had ancestors from an unknown group of humans more ancient than the Bushmen.
Modern Bushmen have been evolving darker skins
Pygmies have been evolving shorter stature
I missed #12-13 on my previous post about this paper, though I did note that the more data we get on ancient African groups, the more likely I think we are to find ancient admixture events. If humans can mix with Neanderthals and Denisovans, then surely our ancestors could have mixed with Ergaster, Erectus, or whomever else was wandering around.
#15 is interesting, and consistent with the claim that Bushmen suffer from a lot of skin cancer–before the Bantu expansion, they lived in far more forgiving climates than the Kalahari desert. But since Bushmen are already lighter than their neighbors, this begs the question of how light their ancestors–who had no Levantine admixture–were. Could the Bantus’ and Nilotics’ darker skins have evolved after the Bushmen/everyone else split?
Meanwhile, in Loci Associated with Skin Pigmentation Identified in African Populations, Crawford et al used genetic samples from 1,570 people from across Africa to find six genetic areas–SLC24A5, MFSD12, DDB1, TMEM138, OCA2 and HERC2–which account for almost 30% of the local variation in skin color.
SLC24A5 is a light pigment introduced to east Africa from the Levant, probably around 3,000 years ago. Today, it is common in Ethiopia and Tanzania.
Interestingly, according to the article, “At all other loci, variants associated with dark pigmentation in Africans are identical by descent in southern Asian and Australo-Melanesian populations.”
These are the world’s other darkest peoples, such as the Jarawas of the Andaman Islands or the Melanesians of Bougainville, PNG. (And, I assume, some groups from India such as the Tamils.) This implies that these groups 1. had dark skin already when they left Africa, and 2. Never lost it on their way to their current homes. (If they had gotten lighter during their journey and then darkened again upon arrival, they likely would have different skin color variants than their African cousins.)
This implies that even if the Bushmen split off (around 200,000-300,000 YA) before dark skin evolved, it had evolved by the time people left Africa and headed toward Australia (around 100,000-70,000 YA.) This gives us a minimum threshold: it most likely evolved before 70,000 YA.
(But as always, we should be careful because perhaps there are even more skin color variant that we don’t know about yet in these populations.)
MFSD12 is common among Nilotics and is related to darker skin.
Further, the alleles associated with skin pigmentation at all loci but SLC24A5 are ancient, predating the origin of modern humans. The ancestral alleles at the majority of predicted causal SNPs are associated with light skin, raising the possibility that the ancestors of modern humans could have had relatively light skin color, as is observed in the San population today.
The full article is not out yet, so I still don’t know when all of these light and dark alleles emerged, but the order is absolutely intriguing. For now, it looks like this mystery will still have to wait.
It was only two years ago that researchers found the first ancient human genome in Africa: a skeleton in a cave in Ethiopia yielded DNA that turned out to be 4,500 years old.
On Thursday, an international team of scientists reported that they had recovered far older genes from bone fragments in Malawi dating back 8,100 years. The researchers also retrieved DNA from 15 other ancient people in eastern and southern Africa, and compared the genes to those of living Africans.
We assembled genome-wide data from 16 prehistoric Africans. We show that the anciently divergent lineage that comprises the primary ancestry of the southern African San had a wider distribution in the past, contributing approximately two-thirds of the ancestry of Malawi hunter-gatherers ∼8,100–2,500 years ago and approximately one-third of the ancestry of Tanzanian hunter-gatherers ∼1,400 years ago.
The San are also known as the Bushmen, a famous group of recent hunter-gatherers from southern Africa.
We document how the spread of farmers from western Africa involved complete replacement of local hunter-gatherers in some regions…
…and we track the spread of herders by showing that the population of a ∼3,100-year-old pastoralist from Tanzania contributed ancestry to people from northeastern to southern Africa, including a ∼1,200-year-old southern African pastoralist…
Whereas the two individuals buried in ∼2,000 BP hunter-gatherer contexts in South Africa share ancestry with southern African Khoe-San populations in the PCA, 11 of the 12 ancient individuals who lived in eastern and south-central Africa between ∼8,100 and ∼400 BP form a gradient of relatedness to the eastern African Hadza on the one hand and southern African Khoe-San on the other (Figure 1A).
The Hadza are a hunter-gatherer group from Tanzania who are not obviously related to any other people. Their language has traditionally been classed alongside the languages of the KhoiSan/Bushmen people because they all contain clicks, but the languages otherwise have very little in common and Hadza appears to be a language isolate, like Basque.
The genetic cline correlates to geography, running along a north-south axis with ancient individuals from Ethiopia (∼4,500 BP), Kenya (∼400 BP), Tanzania (both ∼1,400 BP), and Malawi (∼8,100–2,500 BP), showing increasing affinity to southern Africans (both ancient individuals and present-day Khoe-San). The seven individuals from Malawi show no clear heterogeneity, indicating a long-standing and distinctive population in ancient Malawi that persisted for at least ∼5,000 years (the minimum span of our radiocarbon dates) but which no longer exists today. …
We find that ancestry closely related to the ancient southern Africans was present much farther north and east in the past than is apparent today. This ancient southern African ancestry comprises up to 91% of the ancestry of Khoe-San groups today (Table S5), and also 31% ± 3% of the ancestry of Tanzania_Zanzibar_1400BP, 60% ± 6% of the ancestry of Malawi_Fingira_6100BP, and 65% ± 3% of the ancestry of Malawi_Fingira_2500BP (Figure 2A). …
Both unsupervised clustering (Figure 1B) and formal ancestry estimation (Figure 2B) suggest that individuals from the Hadza group in Tanzania can be modeled as deriving all their ancestry from a lineage related deeply to ancient eastern Africans such as the Ethiopia_4500BP individual …
So what’s up with the Tanzanian expansion mentioned in the summary?
Western-Eurasian-related ancestry is pervasive in eastern Africa today … and the timing of this admixture has been estimated to be ∼3,000 BP on average… We found that the ∼3,100 BP individual… associated with a Savanna Pastoral Neolithic archeological tradition, could be modeled as having 38% ± 1% of her ancestry related to the nearly 10,000-year-old pre-pottery farmers of the Levant … These results could be explained by migration into Africa from descendants of pre-pottery Levantine farmers or alternatively by a scenario in which both pre-pottery Levantine farmers and Tanzania_Luxmanda_3100BP descend from a common ancestral population that lived thousands of years earlier in Africa or the Near East. We fit the remaining approximately two-thirds of Tanzania_Luxmanda_3100BP as most closely related to the Ethiopia_4500BP…
…present-day Cushitic speakers such as the Somali cannot be fit simply as having Tanzania_Luxmanda_3100BP ancestry. The best fitting model for the Somali includes Tanzania_Luxmanda_3100BP ancestry, Dinka-related ancestry, and 16% ± 3% Iranian-Neolithic-related ancestry (p = 0.015). This suggests that ancestry related to the Iranian Neolithic appeared in eastern Africa after earlier gene flow related to Levant Neolithic populations, a scenario that is made more plausible by the genetic evidence of admixture of Iranian-Neolithic-related ancestry throughout the Levant by the time of the Bronze Age …and in ancient Egypt by the Iron Age …
There is then a discussion of possible models of ancient African population splits (were the Bushmen the first? How long have they been isolated?) I suspect the more ancient African DNA we uncover, the more complicated the tree will become, just as in Europe and Asia we’ve discovered Neanderthal and Denisovan admixture.
They also compared genomes to look for genetic adaptations and found evidence for selection for taste receptors and “response to radiation” in the Bushmen, which the authors note “could be due to exposure to sunlight associated with the life of the ‡Khomani and Ju|’hoan North people in the Kalahari Basin, which has become a refuge for hunter-gatherer populations in the last millenia due to encroachment by pastoralist and agriculturalist groups.”
(The Bushmen are lighter than Bantus, with a more golden or tan skin tone.)
They also found evidence of selection for short stature among the Pygmies (which isn’t really surprising to anyone, unless you thought they had acquired their heights by admixture with another very short group of people.)
Overall, this is a great paper and I encourage you to RTWT, especially the pictures/graphs.
Examining ethnically diverse African genomes, we identify variants in or near SLC24A5, MFSD12, DDB1, TMEM138, OCA2 and HERC2 that are significantly associated with skin pigmentation. Genetic evidence indicates that the light pigmentation variant at SLC24A5 was introduced into East Africa by gene flow from non-Africans. At all other loci, variants associated with dark pigmentation in Africans are identical by descent in southern Asian and Australo-Melanesian populations. Functional analyses indicate that MFSD12 encodes a lysosomal protein that affects melanogenesis in zebrafish and mice, and that mutations in melanocyte-specific regulatory regions near DDB1/TMEM138 correlate with expression of UV response genes under selection in Eurasians.
I’ve had an essay on the evolution of African skin tones sitting in my draft folder for ages because this research hadn’t been done. There’s plenty of research on European and Asian skin tones (skin appears to have significantly lightened around 10,000 years ago in Europeans,) but much less on Africans. Luckily for me, this paper fixes that.
Looks like SLC24A5 is related to that Levantine/Iranian back-migration into Africa documented in the first paper.
Some of my baby books make claims like, “Babies are born with blue or grey eyes, most of which gradually darken during their first year.” Some go so far as to claim that all babies are born with blue eyes.
This got me curious: what about Black / African American babies? Are they also born with blue/grey eyes which darken with time? Or were my books over-generalizing from a sample population composed primarily of whites?
The idea isn’t totally crazy. After all, I’ve observed plenty of Caucasian children’s eyes go from blue to brown. Pretty much all infants are born with less melanin than their parents, just because fetuses don’t need protection from sunlight.
To be fair, not all of these photos are necessarily of newborns, but could be somewhat older babies, but this is a process that is supposed to happen over the course of several months to a year, not days.
And while some of these infants do have a greyish or bluish tint to their eyes, the overall color is still brown, not blue.
I suppose I should look up photos of Asian babies while we’re at it.
And… they have brown eyes.
There you go, folks. Asian and African babies have brown eyes, not blue.
There are three categories of supersars who seem to attract excessive female interest. The first is actors, who of course are selected for being abnormally attractive and put into romantic and exciting narratives that our brains subconsciously interpret as real. The second are sports stars and other athletes, whose ritualized combat and displays of strength obviously indicate their genetic “fitness” for siring and providing for children.
The third and strangest category is professional musicians, especially rock stars.
I understand why people want to pass athletic abilities on to their children, but what is the evolutionary importance of musical talent? Does music tap into some deep, fundamental instinct like a bird’s attraction to the courtship song of its mate? And if so, why?
There’s no denying the importance of music to American courtship rituals–not only do people visit bars, clubs, and concerts where music is being played in order to meet potential partners, but they also display musical tastes on dating profiles in order to meet musically-like-minded people.
Of all the traits to look for in a mate, why rate musical taste so highly? And why do some people describe their taste as, “Anything but rap,” or “Anything but country”?
At least when I was a teen, musical taste was an important part of one’s “identity.” There were goths and punks, indie scene kids and the aforementioned rap and country fans.
Is there actually any correlation between musical taste and personality? Do people who like slow jazz get along with other slow jazz fans better than fans of classical Indian? Or is this all compounded by different ethnic groups identifying with specific musical styles?
Obviously country correlates with Amerikaner ancestry; rap with African American. I’m not sure what ancestry is biggest fans of Die Antwoord. Heavy Metal is popular in Finno-Scandia. Rock ‘n Roll got its start in the African American community as “Race Music” and became popular with white audiences after Elvis Presley took up the guitar.
While Europe has a long and lovely musical heritage, it’s indisputable that African Americans have contributed tremendously to American musical innovation.
Here are two excerpts on the subject of music and dance in African societies:
Both of these h/t HBD Chick and my apologies in advance if I got the sources reversed.
One of the major HBD theories holds that the three races vary–on average–in the distribution of certain traits, such as age of first tooth eruption or intensity of an infant’s response to a tissue placed over its face. Sub-Saharan Africans and Asians are considered two extremes in this distribution, with whites somewhere in between.
If traditional African dancing involves more variety in rhythmic expression than traditional European, does traditional Asian dance involve less? I really know very little about traditional Asian music or dance of any kind, but I would not be surprised to see some kind of continuum affected by whether a society traditionally practiced arranged marriages. Where people chose their own mates, it seems like they display a preference for athletic or musically talented mates (“sexy” mates;) when parents chose mates, they seem to prefer hard-working, devout, “good providers.”
Even in traditional European and American society, where parents played more of a role in courtship than they do today, music still played a major part. Young women, if their families could afford it, learned to play the piano or other instruments in order to be “accomplished” and thus more attractive to higher-status men; young men and women often met and courted at musical events or dances organized by the adults.
It is undoubtedly true that music stirs the soul and speaks to the heart, but why?
While tromping through a blizzard, seeking insight into circum-polar peoples, I discovered a condition called chilblains. The relevant Wikipedia page is rather short:
Chilblains … is a medical condition that occurs when a predisposed individual is exposed to cold and humidity, causing tissue damage. It is often confused with frostbite and trench foot. Damage to capillary beds in the skin causes redness, itching, inflammation, and sometimes blisters. Chilblains can be reduced by keeping the feet and hands warm in cold weather, and avoiding extreme temperature changes. Chilblains can be idiopathic (spontaneous and unrelated to another disease), but may also be a manifestation of another serious medical condition that needs to be investigated.
The part they don’t mention is that it can really hurt.
The first HBD-related question I became interested in–after visiting a black friend’s house and observing that she was comfortable without the AC on, even though it was summer–is whether people from different latitudes prefer different temperatures. It seems pretty obvious: surely people from Yakutsk prefer different temperatures than people from Pakistan. It also seems easy to test: just put people in a room and give them complete control over the thermostat. And yet, I’d never heard anyone discuss the idea.
Anyway, the perfunctory Wikipedia page on chilblains mentioned nothing about racial or ethnic predisposition to the condition–even though surely the Eskimo (Inuit) who have genetic admixture from both ice-age Neanderthals and Denisovans:
“Using this method, they found two regions with a strong signal of selection: (i) one region contains the cluster of FADS genes, involved in the metabolism of unsaturated fatty acids; (ii) the other region contains WARS2 and TBX15, located on chromosome 1.” …
“TBX15 plays a role in the differentiation of brown and brite adipocytes. Brown and brite adipocytes produce heat via lipid oxidation when stimulated by cold temperatures, making TBX15 a strong candidate gene for adaptation to life in the Arctic.” …
“The Inuit DNA sequence in this region matches very well with the Denisovan genome, and it is highly differentiated from other present-day human sequences, though we can’t discard the possibility that the variant was introduced from another archaic group whose genomes we haven’t sampled yet,” Dr. Racimo said.
The scientists found that the variant is present at low-to-intermediate frequencies throughout Eurasia, and at especially high frequencies in the Inuits and Native American populations, but almost absent in Africa.
Sub-Saharan Africans have their own archaic admixture, but they have very little to no ice-age hominin–which is probably good for them, except for those who’ve moved further north.
Imagine my surprised upon searching and discovering very little research on whether chilblains disproportionately affects people of different races or ethnicities. If you were a dermatologist–or a genetically prone person–wouldn’t you want to know?
Black individuals have been shown to be 2 to 4 times more likely than individuals from other racial groups to sustain cold injuries. These differences may be due to cold weather experience, but are likely due to anthropometric and body composition differences, including less-pronounced CIVD, increased sympathetic response to cold exposure, and thinner, longer digits.3,6
While I would really prefer to have more ethnic groups included in the study, two will have to suffice. It looks like trench foot may be an equal-opportunity offender, but chilblains, frostbite, and other cold-related injuries attack black men (at least in the army) at about 4x the rate of white men, and black women 2x as often as white women (but women in the army may not endure the same conditions as men in the army.)
On a related note, while researching this post, I came across this historic reference to infectious scurvy and diabetes, in the Journal of Tropical Medicine and Hygiene, Volumes 4-5 (published in 1902):
Note: this is why it is important to discard bad theories after they’ve been disproven. Otherwise, you kill your scurvy victims by quarantining them instead of giving them oranges.
Oh man! We are finally at part three! The part in which I attempt incorporating two-D space into our diagram:
Right, so as we turn our car around and head back up the road, we notice an intriguing turnoff in the Congolese rainforest: a tribe of the shortest people in the world, the Pygmies. According to Wikipedia:
A pygmy is a member of an ethnic group whose average height is unusually short; anthropologists define pygmy as a member of any group where adult men are on average less than 150 cm (4 feet 11 inches) tall. A member of a slightly taller group is termed “pygmoid“.
Basically, whenever humans live in tropical rainforests, there’s a good chance they’ll get shorter. (Rainforests also produce pygmy elephants.) Maybe it’s because short people can move more easily through the dense forest, or an adaptation to low levels of iodine, sunlight, or other nutrients–I don’t really know.
Wikipedia estimates that there are between 250,000 and 600,000 pygmies living in the Congo rainforest:
Genetically, the pygmies are extremely divergent from all other human populations, suggesting they have an ancient indigenous lineage. Their uniparental markers represent the most ancient divergent ones right after those typically found in Khoisan peoples. African pygmy populations possess high levels of genetic diversity, recent advances in genetics shed some light on the origins of the various pygmy groups. …
“We studied the branching history of Pygmy hunter–gatherers and agricultural populations from Africa and estimated separation times and gene flow between these populations. The model identified included the early divergence of the ancestors of Pygmy hunter–gatherers and farming populations ~60,000 years ago, followed by a split of the Pygmies’ ancestors into the Western and Eastern Pygmy groups ~20,000 years ago.”
But I recall–was it WestHunt?–objecting that the authors of this paper used a too-fast estimation of genetic mutation rates. Oh here it is:
There are a couple of recent papers on introgression from some quite divergent archaic population into Pygmies ( this also looks to be the case with Bushmen). Among other things, one of those papers discussed the time of the split between African farmers (Bantu) and Pygmies, as determined from whole-genome analysis and the mutation rate. They preferred to use the once-fashionable rate of 2.5 x 10-8 per-site per-generation (based on nothing), instead of the new pedigree-based estimate of about 1.2 x 10-8 (based on sequencing parents and child: new stuff in the kid is mutation). The old fast rate indicates that the split between Neanderthals and modern humans is much more recent than the age of early Neanderthal-looking skeletons, while the new slow rate fits the fossil record – so what’s to like about the fast rate? Thing is, using the slow rate, the split time between Pygmies and Bantu is ~300k years ago – long before any archaeological sign of behavioral modernity (however you define it) and well before the first known fossils of AMH (although that shouldn’t bother anyone, considering the raggedness of the fossil record).
Let’s split the difference and say that one way or another, Pygmies split off from their hunter-gatherer neighbors and became isolated in the rainforest quite a while ago.
Before we drive on, I’d like to pause and note that I’m not entirely comfortable with using the way Pygmies are sometimes used in racial discussions. Yes, they are short, but they otherwise look a lot like everyone else in the area. Pygmies go to school, often speak multiple languages, live in cities, work at real jobs, read books, operate businesses, drive cars, fall in love, get married, build houses, etc. For more on Pygmies see my review of Isaac Bacirongo’s memoir Still a Pygmy (Isaac is a Pygmy man who speaks, IIRC, 5 languagues, attended highschool, and owned/ran successful pharmacies in two different cities in the DRC before the army burned them down during a civil war.)
Now I admit that Isaac is just one guy and I don’t know what the rest of the Pygmies are like.
But let’s hop back in our car, for at the other end of this road we have not a small town of isolated forest-dwellers, but a large group we have so far neglected: the Native Americans.
The indigenous peoples of North and South America today number about 60 million people, plus some quantity of mixed-race people (mestizos.) In some areas these mestizos are majority European by ancestry; in others they are majority Indian; studies in Mexico, for example, estimate that 80-93% of the population is Mestizo, with Indian ancestry averaging between 31% and 66% in different regions. The people of El Salvador are about 86% mestizo; Chileans are about 40% Indian and 60% Europeans; Columbia is about 49% mestizo; etc.
Unfortunately, Wikipedia doesn’t list the total number of mestizos, and I don’t have time to calculate it, but I will note that the total population of both continents, including Canada and the USA, is about 1 billion people.
We’re not sure exactly when (or how) the Indians got here, but it looks like they arrived around 10-20,000 years ago across the then-Bering Landbridge. (I think we should also keep in mind the possibility that they could have built boats.) According to Wikipedia:
Scientific evidence links indigenous Americans to Asian peoples, specifically Siberian populations, such as the Ket, Selkup, Chukchi and Koryak peoples. Indigenous peoples of the Americas have been linked to North Asian populations by the distribution of blood types, and in genetic composition as reflected by molecular data, such as DNA. There is general agreement among anthropologists that the source populations for the migration into the Americas originated from an area somewhere east of the Yenisei River. The common occurrence of the mtDNA Haplogroups A, B, C, and D among eastern Asian and Native American populations has long been recognized. As a whole, the greatest frequency of the four Native American associated haplogroups occurs in the Altai–Baikal region of southern Siberia. Some subclades of C and D closer to the Native American subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations.
On the grand scale of human history, (200,000 years, more or less,) 13-20,000 years is not very long, and the Native Americans have not diverged too much, physically, from their cousins in Asia. The G-allele mutation of the EDAR gene arose about 30,000 years ago somewhere in east Asia and gives both modern Asians and Native Americans (but not Europeans and Africans) their characteristic hair and skin tone. While Native Americans are clearly physically, culturally, and geographically distinct from other Asians, (just as Europeans and south-Asian Indians are distinct from each other,) they are genetically close enough that they unquestionably clade together in the greater racial schema.
As I’ve said before, my diagram is just one way to represent one aspect of the genetic (and physical) distances between people.
Here is another diagram, not mine, which tells the same story in a different way (though it estimates a much lower genetic distance between Bushmen and Bantus than I’d expect. Oh well. different studies get different results; that’s why replication and meta-analysis are super important):
The Melanesians of Papua New Guinea and Australia are in pink (there are some mixed Melanesian / Polynesian populations in the world, but our road trip skipped them.) Their nearest relatives are other south Asians and Polynesians, but those same south Asians are themselves more closely related to Europeans than Australians. Diagrammed like this, it’d be understandable to break off south Asians into one race and put Caucasians, Native Americans, and East Asians into a single race. And I suppose you could, if you wanted to and could get everyone else to start using your categories. Race is biologically real and quite obvious at the macro scale, but a few small groups like Aborigines and Bushmen introduce existential uncertainty that intellectuals can quibble over.I don’t think it would be terribly useful rearrangement, though, for all of the reasons discussed over the past three posts in this series.
Well, that’s the end of our big road trip! I hope you’ve enjoyed it, and that it’s cleared up that nagging question people seem to have: How can Nigerians be more closely related to Europeans than some other Africans? Have a great day, and enjoy the drive home.
Note: This post contains a lot of oversimplification for the sake of explaining a few things. (Yes, I am still meditating on the greater Asian clade.)
Imagine you’re driving down a long highway that stretches from Nigeria to Beijing, passing through Berlin and New Delhi. In reality this route takes some large twists and turns, but we’re drawing it as a straight line, for all maps must simplify to be useful.
As you drive along, you pass many houses along the way–sometimes just a few clustered next to the highway, sometimes small towns, sometimes megalopolises with billions of people.
Our drive begins in one such megalopolis, that of Sub-Saharan Africa (SSA.) Here we meet people like Queen Anna Nzinga, author Chinua Achebe, and–though they have traveled far abroad–African Americans like Oprah Winfrey and Martin Luther King.
Though thousands of different languages are spoken by the thousands of different groups throughout SSA, we may still note a certain physical similarity among them–dark skin perfectly adapted to the equator’s strong sun, dark eyes, and tightly curling hair. While there is a tremendous amount of variety here–probably the most of any megalopolis in the world–they are also, quite clearly, related. You don’t have to go measuring skulls to figure that out.
But as we drive north, the houses thin out. Suddenly we are in a zone with almost no people–an enormous desert: the Sahara.
We speed through this harsh, empty landscape on a starry night, spotting only a few camels in the distance. We’re lucky we have a full tank of gas and several more in the trunk–for all but the most intrepid of our pre-automobile ancestors, this desert was nigh impassible, a vast barrier to human movement.
Finally we reach the vast inland sea of the Mediterranean, and the beginning of our second megalopolis. Most of the people here, from Berbers to Egyptians, have their own distinct look, more similar to their neighbors from the Middle East and Southern Europe than their neighbors to the south, across the inhospitable expanse of sand.
While there are many different countries and languages, no clear phenotypic line separates the people of Northern Africa, the Middle East, southern Europe, or northern Europe. Skin pales, hair lightens and becomes wavy, eyes turn a variety of hues as one nationality melts into the next. North-central Europe is the only place in the world where blue/green/hazel eyes and blond hair are common in adults; even in Wales, dark hair is dominant.
We hang a right through Turkey, Iran, Pakistan, and India, teeming with people. Here again, though the people change and there are barriers like the Thar Desert, we find no harsh, nigh-impenetarable breaks like the Sahara.
Then, suddenly, we run smack into a wall, a natural wall of majestic proportions: the Himalayas. Beyond lie the Tibetan Plateau, Gobi Desert, and the vast emptiness of the Asian steppe. If this land was ever densely populated, generations of marauding steppe warriors have wiped them out. We see a few people here–aptly named Tibetan lamas, flocks of sheep grazing beside a scattering of yurts. Mongolia holds the distinction of being the world’s least densely populated independent country. (Ice-covered Greenland is even less dense, but owned by Denmark.)
Finally we pass beyond the shadow of the Great Khan’s memorial and into the valley of the Yellow River, where we find our third megalopolis: east Asia.
There is notably less genetic diversity here than in the first megalopolis–indeed, 93% of Han Chinese share a particular variety of the EDAR allele:
A derived G-allele point mutation (SNP) with pleiotropic effects in EDAR, 370A or rs3827760, found in most modern East Asians and Native Americans but not common in African or European populations, is thought to be one of the key genes responsible for a number of differences between these populations, including the thicker hair, more numerous sweat glands, smaller breasts, and dentition characteristic of East Asians. … The 370A mutation arose in humans approximately 30,000 years ago, and now is found in 93% of Han Chinese and in the majority of people in nearby Asian populations.
Here, too, skin tones vary from north to south, though not as greatly as they do closer to the Greenwich Meridian. Most people have dark eyes, slim frames, and straight, smooth black hair.
Here in the megalopolis made famous by Beijing, Shanghai, Hong Kong, Seoul, and Tokyo, we have come to the end of the–first round–of our journey. From Africa to Asia, we have found three vast areas filled with people, and two major barriers which–though not completely impassible–have hindered humanity’s footsteps over the millennia.
People sometimes try to claim that human races do not exist simply because edge cases exist, small, scattered groups which possess a mixture of genes common to both Sub-Saharan Africans and Caucasians, Caucasians and Asians. And these groups do in fact exist, and are fascinating in their own rights. But these groups are also small, often living in extremely harsh, forbidding lands where few humans can survive (The inhabitants of the Himalayas and Tibetan plateau, I note, actually carry a gene that helps them survive at high altitudes which they received via an ancestor’s dalliance with a Denisovan hominin–the Denisovans were cousin to the Neanderthals and lived in Asia long before Homo Sapiens. No one else in the world carries this gene, so if you don’t have it, good luck living up there!)
But the vast, vast majority of the world’s people do not live in these harsh and unforgiving lands. They live clustered together in the enormous population centers, continually mixing, migrating, churning, and conquering each other, not people thousands of miles off. The concept of race stems from this basic observation of the geography of human settlements.
Physical distance is genetic distance, but since my diagram is only two-dimensional, it can only show the genetic distance between two points at a time. The genetic distance between Asians and Caucasians is about 40k years–much shorter than the distance between Sub-Saharan Africans and Caucasians, 70k years. But the distance between Sub-Saharan Africans and Asians is also about 70k years. Although Asians and Caucasians split apart from each other about 40,000 years ago, they are both descended from a single group of ancestors (a handful of Denisovans and Neanderthals excluded) who left sub-Saharan Africa about 70k years ago. We may best think of the relationship between these three groups not as a single highway, but as a triangle with two sides 70k long and one side of 40k. But to accurately add more groups to our journey, (as we shall do on Thursday), we would have to keep adding dimensions, and we are aiming here for simplicity, not n-dimensional hypercubes.
Continuing with our discussion of Leuconoe’s question:
What is your opinion of the “racial invariance hypothesis” which says that poor whites have about the same crime rate as poor blacks and that if you control for socioeconomic status all the differences between the races in crime go away?
First, let’s be clear about what HBD says (and doesn’t say) about crime, race, and poverty (and while we’re at it, IQ):
Genes influence traits like IQ and criminality.
As JayMan is fond of saying, “All human behavioral traits are heritable.” Okay, but what does this mean? Are we slaves to our genetics? Is there a a murder gene that guarantees that you will go out and stab someone to death? Since JayMan has already written a great explanation, I will quote him and urge you to read the rest:
The First Law emerges from studies of twins, studies of adoptees, and (now) sibling genetic similarity studies. In short, when you look at people’s behavior, virtually without exception … you find some effect of the genes on these traits….
How could this be, you may ask? How could such complex and highly specific things be encoded in the DNA and express themselves despite decades of upbringing and childhood experiences? For one, heritability is only probabilistic, not absolute. Few traits are 100% heritable. …
But, it’s important to understand the meaning of the term heritability. Heritability is the degree of variation in a studied population that can be attributed to genetic variation in that population. The cause is the variance in question is always due to some genetic difference, but it doesn’t tell you how direct such genetic influence is. …
So, how iron-clad is the First Law? Clearly, not alltraits are heritable, right? Right. However, there are only a distinct set of exceptions. Traits that are dependent on content aren’t heritable at all. These include what language you speak, in which particular church you worship, what specific political party you identify. However, the degree and manner to which one interacts with these things are very heritable: how proficient you are with language, how church-going you are, how liberal or conservative.
Note that these are not 100% heritable. There is no “guaranteed to stab people” gene, but there are genes that will make you more likely to want to stab people. Environment, “free will,” and random chance also influence how personality traits manifest in individuals.
Edit: It occurs to me that I should actually talk about some of these genes.
An MAOA variant, nicknamed “the warrior gene,” is the most famous of these. Wikipedia states:
A version of the monoamine oxidase-A gene has been popularly referred to as the warrior gene. Several different versions of the gene are found in different individuals, although a functional gene is present in most humans (with the exception of a few individuals with Brunner syndrome). In the variant, the allele associated with behavioural traits is shorter (30 bases) and may produce less MAO-A enzyme. This gene variation is in a regulatory promoter region about 1000 bases from the start of the region that encodes the MAO-A enzyme.
Studies have found differences in the frequency distribution of variants of the MAOA gene between ethnic groups: of the participants, 59% of Black men, 54% of Chinese men, 56% of Maori men, and 34% of Caucasian men carried the 3R allele, while 5.5% of Black men, 0.1% of Caucasian men, and 0.00067% of Asian men carried the 2R allele.
In individuals with the low activity MAOA gene, when faced with social exclusion or ostracism showed higher levels of aggression than individuals with the high activity MAOA gene.
Doubtless there are other genes I’m not aware of.
2. The frequency of different genes varies between genetically-related groups.
The obvious genes here are ones that code for environmental responses, like lactase persistence in groups that have historically practiced dairy farming and dark skin in areas with intense sunlight.
Everyone on earth shares more genes with the people closely related to them than people less-closely related. For example, the Amish are more genetically similar to other Amish than non-Amish. Pygmies are more closely related to other pygmies than non-pygmies. This is why people look like their parents.
There are a lot of people who claim that “race is a social construct.” From a genetic standpoint, this is simply untrue (look at the top of the blog for an example of how geneticists can distinguish between different genetic groups.)
3. The HBD-theory is that the genes for personality/behavioral traits also vary by genetically-related groups, due to historical environmental (including cultural!) pressures.
For example, Polynesians may have been selected for navigational ability, because good navigators populated Polynesia and bad navigators died at sea. Chinese culture may have selected for people willing to work hard and get along even when they don’t really feel like it; and the Inuit may have been selected for the ability to stand really long, dark winters.
Relevant to our discussion, crime rates vary a lot by region:
We’ve discussed warfare in pre-state societies over quite a few posts lately, so I’m going to summarize quickly: anthropological, historical, and archaeological records all document extremely high rates of violence in non-state societies. Anthropologist Napoleon Chagnon actually kept track of both homicides and births among the Yanomamo, and found that Yanomamo men who had killed more people had more children than Yanomamo men who had killed fewer people, providing a direct mechanism for genetic selection for traits related to homicide and other violence.
Many HBD bloggers, such as Peter Frost and HBD Chick, have discussed the ways in which states have discouraged crime, including (especially) executing criminals and thus preventing them from having children. The observed result:
That all said, there are things that no serious HBD-er claims:
A. That all people or sub-groups within a “race” are identical. As Peter Frost wrote, “No, blacks aren’t all alike. Who said they are?” There are smart black people and dumb black people. Hard-working whites and lazy whites. Extroverted Asians and Introverted Asians. Some white groups (like Russians, apparently,) have significantly higher crime rates than other white groups. Even within the US, there are differences between different groups of whites, with significant ethnic divisions between classes and regions.
B. That environmental effects don’t exist or that humans do not respond to incentives. Obviously if it is cold outside I will wear a coat; if a law is passed that jay walkers will be executed, I will immediately stop jaywalking.
C. Observed differences are set in stone. The world is always changing. Where selection pressures change, so do populations.
So to get back to Leuconoe’s first query, I would not be surprised if controlling for socioeconomic status made all (or most) racial differences in criminality disappear. In fact, this is basically what I would expect, because poverty, criminality, and low-IQ are correlated, so controlling for one will tend to control for all of them.
But why on earth would you do this? If we control for bad decisions, most differences in intelligence disappear. If you control for enough differences, differences disappear. But as JayMan says, you can’t just control for a groups entire history; likewise, you can’t just control for all their traits.
Moreover, this still doesn’t get at why different groups have different rates of criminality or poverty in the first place, nor whether A causes B, B causes A, or C causes A and B. And even if you could prove that poverty causes crime, you still haven’t answered why there’s so much more poverty in black communities than in white (or Asian) ones.
The evidence suggests that if there is police racial bias in arrests it is negligible. Victim and witness surveys show that police arrest violent criminals in close proportion to the rates at which criminals of different races commit violent crimes.
There are dramatic race differences in crime rates. Asians have the lowest rates, followed by whites, and then Hispanics. Blacks have notably high crime rates. This pattern holds true for virtually all crime categories and for virtually all age groups.
In 2013, of the approximately 660,000 crimes of interracial violence that involved blacks and whites, blacks were the perpetrators 85 percent of the time. This meant a black person was 27 times more likely to attack a white person than vice versa. A Hispanic was eight times more likely to attack a white person than vice versa.
If New York City were all white, the murder rate would drop by 91 percent, the robbery rate by 81 percent, and the shootings rate by 97 percent.
Both violent and non-violent crime has been declining in the United States since a high in 1993. 2015 saw a disturbing rise in murder in major American cities that some observers associated with “depolicing” in response to intense media and public scrutiny of police activity.
So much for controlling for income. It looks like equally poor whites and blacks still have massively different homicide rates. (Of course, I should note that the US welfare system attempts to put a minimum floor below which people don’t fall. Without intervention, equally poor whites and blacks might be more similar.)
Lotteries can be useful natural experiments; we can use them to test the accuracy of standard sociological theories, in which rich people buy their kids extra smarts, bigger brains, better health, etc.
David Cesarini, who I met at that Chicago meeting, has looked at the effect of winning the lottery in Sweden. He found that the “effects of parental wealth on infant health, drug consumption, scholastic performance and cognitive and non-cognitive skills can be bounded to a tight interval around zero.”
As I once mentioned, there was an important land lottery in Georgia in 1832. The winners received an 160-acre farm. But by 1880, their descendants were no more literate, their occupational status no higher. The families in the top 2/3rds of income managed to hang on to some of their windfall, but lower-income families did not.
West Hunter does note that there is probably a level below which material deprivation really will harm (or kill) you, and that a random windfall in such a situation will do you good, but virtually no one in the modern West lives in famine or near-famine conditions.
(I suspect it is really easy to catch car thieves in Hawaii.)
Occam’s razor suggests that something is going on here.