Adapting to bubonic plague

 

Rash associated with familial Mediterranean fever (Wikicommons – Dr. H.J. Lachman)

 

In the eastern Mediterranean, people were likelier to survive bubonic plague if they had stronger inflammatory responses to infection in their lungs, gut, and other tissues. Today, that natural selection is attested by a high incidence of familial Mediterranean fever.

 

Familial Mediterranean fever is due to mutations that increase the body’s production of pyrin, a protein that assists inflammatory responses to infection of the lungs, gut, and other tissues. It’s common among eastern Mediterranean peoples, like Jews, Syrians, Armenians, Turks, Greeks, and Italians. The most common symptoms are inflammation of the abdominal lining, the joints, and the chest. Some kind of natural selection seems likely because different mutations have evolved independently to produce the same disease within the same geographic region.

 

Several years ago, Greg Cochran suggested this fever might be an adaptation to trypanosome parasites (Leishmaniasis). Recent research now suggests an adaptation to bacteria of the genus Yersinia. Y. pestis causes bubonic plague, whereas Y. pseudotuberculosis and Y. enterocolitica cause gastroenteritis. These pathogens are highly infectious because they decrease the body’s production of pyrin and thus reduce its ability to fight infection. To compensate for this underproduction of pyrin, there seems to have been selection for mutations that cause overproduction of pyrin, hence the high incidence of familial Mediterranean fever in populations that have coexisted with Yersinia bacteria (Loeven et al. 2020).

 

Yepiskoposyan and Harutyunyan (2007) argue that selection for familial Mediterranean fever must have begun more than 2,500 years ago, since one of the alleles responsible for it is found in different communities of the Jewish diaspora, notably Iraqi and North African Jews. That argument doesn’t convince me, since diaspora communities were not reproductively isolated. The mutation could have arisen in one community and then been spread to others by Jewish individuals moving from one place to another.

 

I’m inclined to believe that selection for this fever began with the earliest recorded outbreak of bubonic plague: the Plague of Justinian (541-549 AD), which killed an estimated 25 million people throughout the Mediterranean Basin and the Middle East. An earlier date is nonetheless possible, since Y. pestis has been attested in archaeological finds as far back as 5,000 years ago (Wikipedia 2022).

 

 

References

 

Chung, L.K., Y.H. Park, Y. Zheng, I.E. Brodsky, P. Hearing, D.L. Kastner, J.J. Chae, and J.B. Bliska. (2016). The Yersinia Virulence Factor YopM Hijacks Host Kinases to Inhibit Type III Effector-Triggered Activation of the Pyrin Inflammasome. Cell Host Microbe 20(3):296-306. https://doi.org/10.1016%2Fj.chom.2016.07.018

 

Cochran, G. (2015). Familial Mediterranean fever. West Hunter, January 9. https://westhunt.wordpress.com/2015/01/09/familial-mediterranean-fever/

 

Loeven, N.A., N.P. Medici, and J.B. Bliska. (2020). The pyrin inflammasome in host-microbe interactions. Curr Opin Microbiol 54:77-86. https://doi.org/10.1016/j.mib.2020.01.005

 

Wikipedia (2022). Bubonic plague. https://en.wikipedia.org/wiki/Bubonic_plague#History

 

Yepiskoposyan, L., and A. Harutyunyan. (2007) Population genetics of familial Mediterranean fever: a review. Eur J Hum Genet 15: 911–916. https://doi.org/10.1038/sj.ejhg.5201869

Survival of the nicest-smelling?

 

The Perfume Maker, Rudolf Ernst (1854-1932) (Wikicommons)

 

It has long been known that we vary not only in our sensitivity to different smells but also in our preferences for them—the degree to which they seem pleasant or unpleasant. This variability often contains a large genetic component (Gross-Isseroff et al., 1992; Karstensen and Tommerup, 2012; Keller et al., 2007; Keller et al., 2012; Weiss et al., 2011). In the case of one odor, a single gene explains over 96% of the variability in smell sensitivity (Jaegar et al., 2013). A twin study has similarly found two odorants to be 78% and 73% heritable (Gross-Isseroff, 1992). This hardwiring is selective, however, because sensitivity to other odors can show little or no heritable variation (Hubert et al., 1980). There is also selective hardwiring in smell preferences. Different individuals will perceive androstenone, for instance, as offensive ('sweaty, urinous'), pleasant ('sweet, floral'), or odorless (Keller et al., 2007). It seems that selection has produced specific algorithms in the human brain for specific smells and that these algorithms can differ from one individual to the next (Keller et al., 2007; Knaapila et al., 2012).

This genetic variability exists between men and women, and also between age groups (Keller et al., 2012). Does it also exist between different human populations? The sense of smell does seem to matter more in some than in others, particularly hunter-gatherers:

People pay attention to smells when they are important to their daily lives and are not just part of the sensory and emotional background. This is certainly the case with the Umeda of New Guinea: in a tropical rainforest scent plays as important a role as sight in terms of spatial orientation. The Waanzi in southeast Gabon use odors daily in fishing, hunting, and gathering, thanks to a kind of 'olfactory apprenticeship' in family life and rituals of initiation. In Senegal, the Ndut are even more skillful: they are able to distinguish the odors of the different parts of plants and they are able to give a name to these odors. In our society, of course, most of us are incapable of this. (Candau, 2004)

For hunter-gatherers farther away from the tropics, the sense of smell matters less because the land supports a lower diversity of plant species and has less plant life altogether per unit of land area. Parallel to this north-south trend, more food comes from hunting of game animals and less from gathering of plant items. The end point is Arctic tundra, where opportunities for gathering are limited even in summer and where most food takes the form of meat. There, the senses of sight and sound matter more, being of greater value for long-range detection and tracking of game animals.

Candau (2004) sees these differences between human groups as evidence for "cultural influences" rather than "genetic inheritance." The two are not mutually exclusive: culture itself can select for some heritable abilities over others. On this point, it may be significant that different human groups continue to show differences in smell sensitivity and preference long after their ancestors had moved to very different environments. Thus, in a study from New York City, Euro-American and African American participants were exposed to a wide range of odors. It was found that the two groups differed in their pleasantness rating of 18 of the 134 stimuli, generally floral or vegetative odors. Moreover in 14 of the 18, the African Americans were the ones who responded more positively (Keller et al., 2012).

In addition, the African Americans responded more readily to aromatic metabolites of the male hormone testosterone, i.e., androstadienone and androstenone. The authors note: "This is consistent with the finding from the National Geographic Smell Survey, which found that African respondents were more sensitive to androstenone than American respondents. This difference is undoubtedly at least partially caused by the fact that the functional RT variant of OR7D4 is more common in African-Americans than in Caucasians" (Keller et al., 2012).

Gene-culture coevolution during historic times

This coevolution did not stop with hunter-gatherers. Beginning 10,000 years ago, some of them became farmers and that change set off a lot of other changes: population growth, land ownership, creation of a class system, social inequality on a much greater scale, year-round settlement in villages and then in towns and cities ... And on and on. We entered new environments—not natural ones of climate and vegetation, but rather human-made ones.

These environments offered us new olfactory stimuli: salves, perfumes, incense, scented oils, aromatic baths ... Havlicek and Roberts (2013) argue that our sense of smell coevolved with human-made fragrances and that this coevolution went on for the longest in the Middle East and South Asia, where the use of perfumes is attested as early as the fourth millennium B.C. (Wikipedia, 2015). A sort of positive feedback then developed between use of these fragrances and praise of them in prose, song, and poetry, the two reinforcing each other and thereby strengthening the pressure of selection. This may be seen in the Bible:

The Hebrew Song of Songs furnishes a typical example of a very beautiful Eastern love-poem in which the importance of the appeal to the sense of smell is throughout emphasized. There are in this short poem as many as twenty-four fairly definite references to odors,—personal odors, perfumes, and flowers,—while numerous other references to flowers, etc., seem to point to olfactory associations. Both the lover and his sweetheart express pleasure in each other's personal odor. 

"My beloved is unto me," she sings, "as a bag of myrrh

That lieth between my breasts;
My beloved is unto me as a cluster of henna flowers
In the vineyard of En-gedi."

And again: "His cheeks are as a bed of spices [or balsam], as banks of sweet herbs." While of her he says: "The smell of thy breath [or nose] is like apples." (Ellis, 1897-1928)

In the 9th century the Arab chemist Al-Kindi wrote the Book of the Chemistry of Perfume and Distillations, which contained more than a hundred recipes for fragrant oils, salves, and aromatic waters (Wikipedia, 2015). Today, the names of our chief perfumes are often of Arabic or Persian origin: civet, musk, ambergris, attar, camphor …

Finally, the use of perfumes, like kissing and cosmetics in general, moved the center of sexual interest away from the genitals and toward the face, thereby creating a second channel of arousal:

[...] the focus of olfactory attractiveness has been displaced. The centre of olfactory attractiveness is not, as usually among animals, in the sexual region, but is transferred to the upper part of the body. In this respect the sexual olfactory allurement in man resembles what we find in the sphere of vision, for neither the sexual organs of man nor of woman are usually beautiful in the eyes of the opposite sex, and their exhibition is not among us regarded as a necessary stage in courtship. The odor of the body, like its beauty, in so far as it can be regarded as a possible sexual allurement, has in the course of development been transferred to the upper parts. The careful concealment of the sexual region has doubtless favored this transfer. (Ellis, 1897-1928)

Differences between human populations?

To recapitulate, we humans vary a lot in the degree to which we have been exposed to perfumes and to a perfume-friendly culture, a possible analogy being the degree to which we have been exposed to alcoholic beverages. There may thus have been selection against individuals whose own smell preferences or body chemistry failed to match the perfumes available, this selection being not only stronger in some populations but also qualitatively different:

[...] individual communities vary considerably in the substances they employ for perfume production (in most of the speculations below we deliberately ignore recent trends such as technological advancement in global transfer of goods and production of synthetic chemicals used in perfumery: these phenomena appeared only very recently and one might not expect their immediate effect on biological evolution which operates on a much longer time scale). The absence of a specific ingredient in the perfumes of a particular community could be due to the following reasons: (1) the source of the odour is unavailable in the area and is not traded from neighbours. For example, we know that aromatic plants were an important commodity in trading networks in Ancient Egypt or Greece, but some of the scents routinely employed in that era in India were rare or absent in Mediterranean cultures. (2) The community is constrained by a technology. Some of the aromas can be extracted only using a specific technology which might not be available for or discovered by the particular community. In ancient Greece, for instance, ethanol distillation was not used and perfumers instead used mechanic extraction or enfleurage (Brun 2000). (3) Particular scents or their source (e.g. a particular plant) are believed to be inappropriate for body adornment. Such beliefs might stem from religious considerations.

[...] considering that only some scent ingredients will complement particular body odours (i.e. particular genotypes) and that a particular community employs only a restricted variety of scents for perfuming, it is plausible that some individuals may not be able to select a perfume which complements their body odour and may therefore suffer a social disadvantage. In the long run, the frequency of genotypes of such individuals would decrease in the particular community. (Havlicek and Roberts, 2013)

It is disappointing that Havlicek and Roberts do not develop this argument further with plausible evidence for such gene-culture coevolution. For instance, Hall et al. (1968) discussed how smell and touch hold greater importance for Arabs than for Americans. This point has likewise been remarked upon with respect to the Gulf countries:

The importance of good smell in Qatari homes is inherent in the requirement of cleanness and purity (taharah) in Islam, both physical and spiritual (Sobh and Belk, 2010). Purity, cleanness, and good smell are central to Muslims everywhere in the world, but the obsession with perfuming bodies and homes is something of a fetish in Gulf countries and is very prominent in Qatar. (Sobh and Belk, 2011)

This heightened smell sensitivity is all the more striking because plant life is less abundant and less diverse in the Middle East, certainly in comparison with the tropics. It seems unlikely, then, that it had been acquired during the hunter-gatherer stage of cultural evolution, being instead a later development, possibly through coevolution with the development of perfumes in historic times.

References 

Candau, J. (2004). The olfactory experience: constants and cultural variables, Water Science & Technology, 49, 11-17.

https://halshs.archives-ouvertes.fr/halshs-00130924/  

Ellis, H. (1897-1928). Studies in the Psychology of Sex, vol. IV, Appendix A. The origins of the kiss.

https://www.gutenberg.org/files/13613/13613-h/13613-h.htm 

Gross-Isseroff, R., D. Ophir, A. Bartana, H. Voet, and D. Lancet. (1992). Evidence for genetic determination in human twins of olfactory thresholds for a standard odorant, Neuroscience Letters, 141, 115-118.

http://www.sciencedirect.com/science/article/pii/030439409290347A 

Hall, E.T., R.L. Birdwhistell, B. Bock, P. Bohannan, A.R. Diebold, Jr., M. Durbin, M.S. Edmonson, J.L. Fischer, D. Hymes, S.T. Kimball, W. La Barre, F. Lynch, J.E. McClellan, D.S. Marshall, G.B. Milner, H.B. Sarles, G. L Trager, and A.P. Vayda  (1968). Proxemics, Current Anthropology, 9, 83-108

http://www.jstor.org/stable/2740724?seq=1#page_scan_tab_contents 

Havlícek, J., and S.C. Roberts (2013). The Perfume-Body Odour Complex: An Insightful Model for Culture-Gene Coevolution? Chemical Signals in Vertebrates, 12, 185-195.

http://www.scraigroberts.com/uploads/1/5/0/4/15042548/2013_csiv_perfume.pdf 

Hubert, H.B., R.R. Fabsitz, M. Feinleib, and K.S. Brown. (1980). Olfactory sensitivity in humans: genetic versus environmental control, Science, 208, 607-609.

http://www.sciencemag.org/content/208/4444/607.short 

Jaeger, S.R., J.F. McRae, C.M. Bava, M.K. Beresford, D. Hunter, Y. Jia et al. (2013). A Mendelian Trait for Olfactory Sensitivity Affects Odor Experience and Food Selection, Current Biology, 23, 1601 - 1605

http://www.cell.com/current-biology/abstract/S0960-9822(13)00853-1?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982213008531%3Fshowall%3Dtrue 

Knaapila, A., G. Zhu, S.E. Medland, C.J. Wysocki, G.W. Montgomery, N.G. Martin, M.J. Wright, D.R. Reed. (2012). A genome-wide study on the perception of the odorants androstenone and galaxolide, Chemical Senses, 37, 541-552.

http://www.researchgate.net/profile/Danielle_Reed2/publication/221859158_A_genome-wide_study_on_the_perception_of_the_odorants_androstenone_and_galaxolide/links/02e7e52b367564a573000000.pdf

Karstensen, H.G. and N. Tommerup. (2012). Isolated and syndromic forms of congenital anosmia, Clinical Genetics, 81, 210-215. 

Keller, A., M. Hempstead, I.A. Gomez, A.N. Gilbert and L.B Vosshall. (2012). An olfactory demography of a diverse metropolitan population, BMC Neuroscience, 13, 122

http://www.biomedcentral.com/1471-2202/13/122/ 

Keller, A., H. Zhuang, Q. Chi, L.B. Vosshall, and H. Matsunami. (2007). Genetic variation in a human odorant receptor alters odour perception, Nature, 449, 468-472

http://vosshall.rockefeller.edu/reprints/KellerMatsunamiNature07.pdf

Sobh, R. and R. Belk. (2011). Domains of privacy and hospitality in Arab Gulf homes, Journal of Islamic Marketing, 2, 125-137

http://www.researchgate.net/profile/Rana_Sobh/publication/241699027_Domains_of_privacy_and_hospitality_in_Arab_Gulf_homes/links/54a1374b0cf257a63602614b.pdf

Weiss, J., M. Pyrski, E. Jacobi, B. Bufe, V. Willnecker, B. Schick, P. Zizzari, S.J. Gossage, C.A. Greer, T. Leinders-Zufall, et al. (2011). Loss-of-function mutations in sodium channel Nav1.7 cause anosmia, Nature, 472, 186-190. 

Wikipedia (2015). Perfume

https://en.wikipedia.org/wiki/Perfume 

Not everyone does it

 

Un homme et une femme, 1891, Stephan Sinding (1846-1922). Almost as fun as sex.

 

All humans love to kiss, so kissing must go back to early hominids and even chimps and bonobos. This is how ethologists and evolutionary psychologists think when they write about the subject.

Just one thing. Even in historic times not all humans loved to kiss. Far from arising millions of years in the past, kissing seems to have arisen no earlier than 40,000 years ago, when modern humans began to enter northern Eurasia.

So concludes a recent cross-cultural study:

We found only 77 out of 168 (46%) cultures in which the romantic-sexual kiss was present. Significantly, no ethnographer working with Sub-Saharan African, New Guinea, or Amazonian foragers or horticulturalists reported having witnessed any occasion in which their study populations engaged in a romantic-sexual kiss. However, kissing appears to be nearly ubiquitous among 9 of the 11 foragers living in Circum-Arctic region (i.e., northern Asia and North America). The concentration of kissing among Circum-Arctic foragers, for which we do not have a satisfactory explanation other than invoking cultural diffusion, stands in stark contrast to its equally striking absence among foragers in other cultural regions. (Jankowiak et al., 2015)

This is not the first study to deny the universality of kissing, although scholars have tended to place its origin in the civilizations of the Mediterranean, the Middle East, and South Asia (Hawley, 2007; Hopkins, 1907). The English sexologist Havelock Ellis argued that kissing began with "civilized man": 

It is only under a comparatively high stage of civilization that the kiss has been emphasized and developed in the art of love. Thus the Arabic author of the Perfumed Garden, a work revealing the existence of a high degree of social refinement, insists on the great importance of the kiss, especially if applied to the inner part of the mouth, and he quotes a proverb that "A moist kiss is better than a hasty coitus." Such kisses, as well as on the face generally, and all over the body, are frequently referred to by Hindu, Latin, and more modern erotic writers as among the most efficacious methods of arousing love. (Ellis,1897-1928)

It may be that kissing originated in prehistory among the hunter-gatherers of northern Eurasia and then spread south, where it reached its full flowering in a milieu that idealized it in prose, poetry, and painting. A kind of positive feedback thus developed between the practice and the ideal.

Then, at a later date, it became less common in northern Europe because of the moral climate that followed the Reformation, having been previously very common. When the Greek scholar Demetrios Chalkokondyles (1423-1511) visited England, he was surprised by its ubiquity:

As for English females and children, their customs are liberal in the extreme. For instance, when a visitor calls at a friend's house, his first act is to kiss his friend's wife; he is then a duly-installed guest. Persons meeting in the street follow the same custom, and no one sees anything improper in the action. (Bombaugh, 1876, p. 33)

Another Greek traveler likewise remarked a century later:

The English manifest much simplicity and lack of jealousy in their customs as regards females; for not only do members of the same family and household kiss them on the lips with complimentary salutations and enfolding of the arms around the waist, but even strangers, when introduced, follow the same mode, and it is one which does not appear to them in any degree unbecoming. (Bombaugh, 1876, p. 33)

Similar comments were made by Erasmus (1467-1536):

If you go to any place, you are received with a kiss by all; if you depart on a journey, you are dismissed with a kiss; if you return, the kisses are exchanged. Do they come to visit you, a kiss is the first thing; do they leave you, you kiss them all around. Do they meet you anywhere, kisses in abundance. In short, wherever you turn, there is nothing but kisses. Ah, Faustus, if you had once tasted the tenderness, the fragrance of these kisses, you would wish to stay in England, not for ten years only, but for life. (Bombaugh, 1876, p. 34)

Kissing then fell into decline among the English; so much so, that frequent public displays became seen as a continental thing. Nonetheless, it remained much more common than in other parts of the world, particularly East Asia and sub-Saharan Africa. This difference amused travelers as late as the 19th century:

An American naval officer, who had spent considerable time in China, narrates an amusing experience of the ignorance of the Chinese maidens of the custom of kissing. Wishing to complete a conquest he had made of a young mei jin (beautiful lady), he invited her—using the English words—to give him a kiss. Finding her incomprehension of his request somewhat obscure, he suited the action to the word and took a delicious kiss. The girl ran away into another room, thoroughly alarmed, exclaiming, "Terrible man-eater, I shall be devoured." (Bombaugh, 1876, p. 80)

For the same time period, Havelock Ellis noted: "Kisses, and embraces are simply unknown in Japan as tokens of affection" with the exception of mothers hugging and kissing their infants. Similarly, "among nearly all of the black races of Africa lovers never kiss nor do mothers usually kiss their babies." He then went on to argue that the romantic kiss evolved out of this maternal kissing, which seems more or less universal.

With the globalization of culture through movies, magazines, and other media, kissing has been spread to the four corners of the earth. Clearly, we can all do it and enjoy doing it to some extent. But I don't think we all share the same urge to do it.

Gene-culture coevolution?

Don't laugh. Even religiosity is partly genetic, so why not the desire to kiss and be kissed? What little we know about the subject comes from studies of compulsive kissing syndrome, where a lesion to the right temporal lobe (associated with epilepsy or glioma) causes an uncontrollable urge to kiss anyone independently of sexual interest (Mendez and Shapira, 2014; Mikata et al., 2005; Ozkara et al., 2004). This compulsion differs from other disorders where increased kissing results from loss of sexual inhibition and is targeted at sexually desirable individuals. The brain may thus have a pre-formed circuit that triggers the desire to kiss. In short, kissing is not solely learned. It has an innate component.

At first, this innate component would have been the same in all humans, back when kissing mainly happened between a mother and her infants. It then became more sexual and more important among the hunter-gatherers of northern Eurasia. Later still, in Europe and the Middle East, it developed into a second channel of sexual arousal almost on a par with the sex act itself.

As Havelock Ellis observed:

[...] there is certainly no such channel for directing nervous force into the sexual sphere as the kiss. This is nowhere so well recognized as in France, where a young girl's lips are religiously kept for her lover, to such an extent, indeed, that young girls sometimes come to believe that the whole physical side of love is comprehended in a kiss on the mouth; so highly intelligent a woman as Madam Adam has described the agony she felt as a girl when kissed on the lips by a man, owing to the conviction that she had thereby lost her virtue.

Sexual kissing initially arose through people pushing the envelope of phenotypic plasticity. This envelope in turn became part of the environment that people had to fit into. Those who couldn't, or wouldn't, were at a disadvantage and were bit by bit pushed out of the gene pool. Those who could, and would, took their place. New genetic variants thus arose and flourished, some to strengthen the new behavior and others to make it more pleasurable.

In this, and in many other ways, Man has created Man. We humans have shaped our environment, which in turn has shaped us, even in our genes. This point becomes clear only if one abandons the assumption, so dear to evolutionary psychology, that we stopped evolving back in the Pleistocene. We didn't. In fact, most of the interesting stuff has come about since then.

References 

Bombaugh, C.C. (1876). The Literature of Kissing, gleaned from history, poetry, fiction, and anecdote, Philadelphia: J.B. Lippincott & Co.

https://books.google.ca/books?id=p9lPAAAAYAAJ&printsec=frontcover&hl=fr&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false  

Ellis, H. (1897-1928). Studies in the Psychology of Sex, vol. IV, Appendix A. The origins of the kiss.

https://www.gutenberg.org/files/13613/13613-h/13613-h.htm 

Hawley, R. (2007). 'Give me a thousand kisses': the kiss, identity, and power in Greek and Roman antiquity, Leeds International Classical Studies, 6.5

http://pdf.thepdfportal.net/?id=123399 

Hopkins, E.W. (1907). The sniff-kiss in ancient India, Journal of the American Oriental Society, 28, 120-134.

http://www.jstor.org/stable/592764?seq=1#page_scan_tab_contents 

Jankowiak, W.R., S.L. Volsche, J.R. Garcia. (2015). Is the Romantic-Sexual Kiss a Near Human Universal? American Anthropologist, early view

http://onlinelibrary.wiley.com/wol1/doi/10.1111/aman.12286/abstract 

Mendez, M.F. and J.S. Shapira. (2014). Kissing or "Osculation" in Frontotemporal Dementia, The Journal of Neuropsychiatry & Clinical Neurosciences, 26, 258-261.

http://neuro.psychiatryonline.org/doi/full/10.1176/appi.neuropsych.13060139 

Mikati, M.A., Y.G. Comair, A.N. Shamseddine. (2005). Pattern-induced partial seizures with repetitive affectionate kissing: an unusual manifestation of right temporal lobe epilepsy. Epilepsy & Behavior, 6, 447-451

http://www.sciencedirect.com/science/article/pii/S1525505005000144 

Ozkara, C., H. Sarý, L. Hanoglu, et al. (2004). Ictal kissing and religious speech in a patient with right temporal lobe epilepsy, Epileptic Disorders, 6, 241-245

http://www.jle.com/fr/revues/epd/e-docs/ictal_kissing_and_religious_speech_in_a_patient_with_right_temporal_lobe_epilepsy__265692/article.phtml?tab=download&pj_key=doc_alt_2458

A look at an early European

 

Kostenki Man, reconstructed by Mikhail Gerasimov (1907-1970). An early European who was not yet phenotypically European.

 

Who were the first Europeans? We now have a better idea, thanks to a new paper about DNA from a man who lived some 38,700 to 36,200 years ago. His remains were found at Kostenki, a well-known Upper Paleolithic site in central European Russia (Seguin-Orlando et al., 2014).

Kostenki Man tells us several things about the first Europeans and, more broadly, the first non-African humans:

The Neanderthal encounter

Modern humans received their Neanderthal admixture when they were just spreading out of Africa some 54,000 years ago. At that time, they had not yet encountered the Neanderthals and were entering the territory of the Skhul/Qafzeh hominids, a semi-archaic people of the Middle East. So we may have got our Neanderthal admixture indirectly. The Skhul/Qafzeh hominids had probably interbred with their Neanderthal neighbors to the north, and our ancestors may have then picked up this admixture while in the Middle East. 

When our ancestors spread farther north into Europe, some 45,000 to 42,000 years ago, they could have interbred directly with Neanderthals, but they didn't. Perhaps the two groups were just too different. They seem to have intermixed only via a third party that was neither fully modern nor fully archaic.

A strange detour ... and then another!

There was initially a large continuous population across northern Eurasia, perhaps composed of nomads who pursued wandering herds of reindeer across the European Plain and its eastward extension into central and northern Asia.

Not long before the time of Kostenki Man, these Northern Eurasians began to split into three regional groups: Western Eurasians, Eastern Eurasians, and the ancestors of Middle Eastern farmers. The degree of reproductive isolation is unclear, however, and gene flow may have continued between all three groups until the onset of the last ice age some 25,000 years ago. This may be why Kostenki Man does not fit perfectly into any of the three groups, although he is genetically closest to Western Eurasians.

Yes, Northern Eurasians were ancestral to the early farming peoples of the Middle East. It seems that early modern humans had to head north, learn to hunt reindeer, and then head south again before they could start farming. Sounds like a strange detour. Wouldn't it have been easier to stay put and do it locally? You know, Middle-Eastern hunter-gatherers becoming Middle Eastern farmers? Apparently not.

It gets even more convoluted. After some of those Northern Eurasians had gone south to the Middle East, some of their farming descendants "returned" to Europe and partially replaced its hunter-gatherers, particularly in southern and central Europe. This second detour has been greeted with disbelief. Dienekes (2014), for instance, has written: "I don't think many archaeologists would derive European farmers from Russia (Russia is actually one of the last places in Europe that became agricultural)."

True, but farming requires a mindset that may have come from those northern hunters (Frost, 2014). When Piffer (2013) looked at human variation in alleles at COMT, a gene linked to executive function, working memory, and intelligence, he found that northern hunting peoples had more in common with farming peoples than with other hunter-gatherers, "possibly due to the higher pressure on technological skills and planning abilities posed by the adverse climatic conditions."

That mindset made farming possible, but the first steps toward farming could not be taken in a cold climate. They had to be taken in a place with a long growing season and a wide variety of domesticable plants and animals, such as in the Middle East. Once farming had developed there, it could move back north, while taking along its technologies, its food crops, and its livestock species. 

Farming can develop in the tropics with a "tropical" mindset, but it looks very different. The farming that arose in West Africa is overwhelmingly women's work and seems to have wholly developed out of female plant gathering. The guinea fowl is the only animal that has been domesticated for food consumption in sub-Saharan Africa.

The Ice Age was not so bad 

The Upper Paleolithic humans of northern and eastern Europe did not die out during the last ice age, as was commonly thought. They survived the glacial maximum intact.

The European phenotype came later

Kostenki Man was dark-skinned, dark-eyed, and rather short. These details, curiously enough, appear not in the paper but in a review of the paper, published by the same journal, as well as in an interview with one of the authors (Associated Press, 2014; Gibbons, 2014). 

So we now have an upper bound for the emergence of the European phenotype, i.e., light skin and a diverse palette of hair and eye colors. The lower bound has been set by the remains of a Swedish hunter-gatherer, dated to 8,000 years ago, who had the "European" allele for light skin at the gene SLC24A5 (Skoglund et al., 2014).

Conclusion

My main criticism centers on the dating to 38,700 - 36,200 years ago. At the Kostenki site, the radiocarbon dating used to be some 10,000 years younger. It was then recalibrated to an older range of dates when a layer of volcanic ash at the site was attributed to a volcano that had erupted in southern Italy some 39,000 years ago. This recalibration was initially controversial, but the controversy has since subsided (Sinitsyn and Hoffecker, 2006). I would not rule out a subsequent re-recalibration.

By retrieving ancient DNA from an early modern human, we have made a key advance in human paleogenetics, perhaps more so than by sequencing the Neanderthal genome. We again see that evolution did not slow down with the emergence of anatomically and behaviorally modern humans some 60,000 years ago. It actually began to speed up, as humans began to enter not only new natural environments but also new cultural environments of their own making.

 

References 

Associated Press (2014). DNA study dates Eurasian split from East Asians, The Columbus Dispatch, November 6

http://hosted2.ap.org/OHCOL/07e34bb59e064cedb7e2776e8db4b4f7/Article_2014-11-06-EU--Eurasian%20Split/id-ae36fa368c634c7383d807942bd5fe67 

Dienekes (2014). Genome of Kostenki-14, an Upper Paleolithic European (Seguin-Orlando, Korneliussen, Sikora, et al. 2014), Dienekes' Anthropology Blog, November 7

http://dienekes.blogspot.ca/2014/11/genome-of-kostenki-14-upper-paleolithic.html  

Frost, P. (2014). The first industrial revolution, Evo and Proud, January 18

http://evoandproud.blogspot.ca/2014/01/the-first-industrial-revolution.html 

Gibbons, A. (2014). European genetic identity may stretch back 36,000 years, Science, News, November 6

http://news.sciencemag.org/archaeology/2014/11/european-genetic-identity-may-stretch-back-36000-years 

Piffer, D. (2013). Correlation of the COMT Val158Met polymorphism with latitude and a hunter-gather lifestyle suggests culture-gene coevolution and selective pressure on cognition genes due to climate, Anthropological Science, 121, 161-171.

https://lesacreduprintemps19.files.wordpress.com/2014/01/correlation-of-the-comt-val158met-polymorphism-with-latitude-and-a-hunter-gather-lifestyle-suggests-culturee28093gene-coevolution-and-selective-pressure-on-cognition-genes-due-to-climate.pdf 

Seguin-Orlando, A., T.S. Korneliussen, M. Sikora, A.-S. Malaspinas, A. Manica, I. Moltke, A. Albrechtsen, A. Ko, A. Margaryan, V. Moiseyev, T. Goebel, M. Westaway, D. Lambert, V. Khartanovich, J.D. Wall, P.R. Nigst, R.A. Foley, M.M. Lahr, R. Nielsen, L. Orlando, and E. Willerslev. (2014). Genomic structure in Europeans dating back at least 36,200 years, Science, Published online 6 November 2014

http://www.sciencemag.org/content/early/2014/11/05/science.aaa0114
http://www2.zoo.cam.ac.uk/manica/ms/2014_Seguin_Orlando_et_al_Science.pdf  

Sinitsyn, A.A., and J.F. Hoffecker. (2006). Radiocarbon dating and chronology of the Early Upper Paleolithic at Kostenki, Quaternary International, 152-153, 164-174.

http://www.sciencedirect.com/science/article/pii/S1040618206000206 

Skoglund, P., H. Malmstrom, A. Omrak, M. Raghavan, C. Valdiosera, T. Gunther, P. Hall, K. Tambets, J. Parik, K-G. Sjogren, J. Apel, E. Willersley, J. Stora, A. Gotherstrom, and M. Jakobsson. (2014). Genomic diversity and admixture differs for stone-age Scandinavian foragers and farmers, Science, 344 (6185), 747-750.

http://www.sciencemag.org/content/344/6185/747.short

 

A fruitful encounter

 

Original Sin, by Michiel Coxie (1499-1592). Did the Christian doctrine of original sin create the guilt cultures of Northwest Europe? Or did the arrow of causality run the other way? (source: Wikicommons)

 

By definition, gene-culture co-evolution is reciprocal. Genes and culture are both in the driver's seat. This point is crucial because there is a tendency to overreact to cultural determinism and to forget that culture does matter, even to the point of influencing the makeup of our gene pool. Through culture, humans have directed their own evolution.

Take the ability to digest lactose, commonly called milk sugar. Among early humans, only babies could digest it because only they made the enzyme that breaks it down. This enzyme was lost as one grew up, with the result that milk consumption would cause indigestion, abdominal gas, and diarrhea. This is still the case in humans from much of Africa and Asia.

Then some cultures began to domesticate cattle, initially for meat. In times of famine, they turned to milk, and those who could better tolerate it had better chances of survival. So there was now natural selection for individuals who could produce the necessary enzyme not only in childhood but in adulthood as well.

The resulting evolutionary change was both genetic and cultural. With more and more adults being able to digest milk, it became possible to develop various dairy products, like cheese, and use milk as an ingredient in a wide range of foods. It also became possible to select for cattle that produce more and better milk (Beja-Pereira et al., 2003). A new way of life developed and thus brought about even more selection for this enzyme.

In sum, a genetic change can open up new paths for culture to follow and thereby create new paths for genes to follow. But that isn't all. The same situation can develop even when no genetic change has taken place, at least not initially. We see this, for instance, when a culture spreads out of one population and into another. The gene-culture interaction is new even though neither party to the interaction is new.

 

A fruitful encounter

One specific example is the encounter between Christianity and the guilt cultures of Northwest Europe, which differ from the shame cultures that prevail elsewhere. The difference is a major one. In a shame culture, your wrongdoings are punished only when witnessed by someone from your community. In a guilt culture, they are punished even when there is no witness, other than the one inside your head.

Guilt culture is commonly attributed to the Christian doctrine of original sin, and more specifically to the radicalization of this doctrine under Protestantism (see Note 1). Yet neither of these presumed causes really lines up with the presumed effect.

For one thing, it's doubtful whether this doctrine was even known to early Christians in the Middle East. True, Paul did write that humans had lost their immortality because of Adam's sin:

Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned. Romans 5.12

This belief also appears in the Talmud, but it was never understood there as meaning that people are sinful because they inherit Adam's burden of sin. The Jewish view, like the later Muslim one, has been that people are sinful because they are imperfect beings. This was probably also the view of early Christians. Even today, Eastern Christians reject the doctrine of original sin, preferring the term "ancestral sin":

In the Orthodox Christian understanding, they explicitly deny that humanity inherited guilt from anyone. Rather, they maintain that we inherit our fallen nature. While humanity does bear the consequences of the original, or first, sin, humanity does not bear the personal guilt associated with this sin. (Original sin, 2014)

It was among Western Christians—Roman Catholics and, later, Protestants—that original sin developed into a doctrine. We see this in the writings of Irenaeus (2nd century) and Augustine (354-430), who identified the original sin as concupiscence, i.e., ardent, sensual longing. Protestantism is then said to have radicalized this doctrine, as seen in the Augsburg Confession of Lutheranism:

It is also taught among us that since the fall of Adam all men who are born according to the course of nature are conceived and born in sin. That is, all men are full of evil lust and inclinations from their mothers' wombs and are unable by nature to have true fear of God and true faith in God. Moreover, this inborn sickness and hereditary sin is truly sin and condemns to the eternal wrath of God all those who are not born again through Baptism and the Holy Spirit. 

But this radicalization was already under way before Protestantism. An English Catholic, Anselm of Canterbury (1033-1109), was the one who first separated original sin from concupiscence and defined it as "privation of the righteousness that every man ought to possess" (Original sin, 2014). Within Western Christendom, pre-Protestant England was likewise the epicenter of an intense penitential tradition that dated back at least to Anglo-Saxon times (Frantzen 1983). This tradition can be summed up as follows: "it is better to be shamed for one's sins before one man (the confessor) in this life than to be shamed before God and before all angels and before all men and before all devils at the Last Judgement" (Godden, 1973). The English abbot Aelfric of Eynsham (955-1010) described the need to do penance for all shameful acts, even those that are witnessed solely by spirits of the dead: 

He who cannot because of shame confess his faults to one man, then it must shame him before the heaven-dwellers and the earth-dwellers and the hell-dwellers, and the shame for him will be endless. (Bedingfield, 2002, p. 80)

Conclusion

As evidenced by the doctrine of original sin and the penitential tradition, Northwest European guilt culture was not a product of Christianity in general or of Protestantism in particular. It seems to have its origins in pre-existing tendencies that were absorbed into the new spiritual environment, much like the Christmas tree and other formerly pagan traditions. It thus grew steadily more important as the geocenter of Christianity moved steadily west and north.

This is not to belittle Christianity’s role. The new faith created ideological, social, and physical structures that were better at enforcing moral norms than anything beforehand. These norms may have had pagan antecedents, but they were now being enforced much more thoroughly.

We see this in the Medieval Synthesis that took hold from the 11th century onward, when Church and State joined forces to defend the Christian world: externally, through military campaigns against Muslims in the Iberian Peninsula, southern Italy, and the Middle East; and internally, through vigorous efforts to pacify social relations, either by increased use of capital punishment or by the Pax Dei—a Church-led movement to limit the scope of war in feudal society (Peace and Truce of God, 2014). Finally, guilt culture was strengthened through confession of one's sins, particularly after this practice became mandatory with the Fourth Lateran Council (1215). All wrongdoings had to be atoned at least once a year, however private or personal they might be (Sacrament of Penance, 2014).

Medieval Christian culture favored the survival and reproduction of people who previously would not have survived and reproduced. Conversely, by criminalizing personal violence, particularly in cases where the offender felt no guilt or remorse, this culture was now eliminating people for behavior that had once been admired.

It is often believed that Europe took off from the 15th century onward, when it expanded into Africa, the Americas, and Asia. Actually, the takeoff began earlier, particularly during this period when Church and State teamed up to lay a new basis for social relations. It was this new moral order that enabled Europe to get ahead (Frost, 2012). As Thomas Hobbes (1588-1679) wrote, no advanced society can develop where men have no "other security than what their own strength and their own invention shall furnish them withal." 

In such condition there is no place for industry, because the fruit thereof is uncertain: and consequently no culture of the earth; no navigation, nor use of the commodities that may be imported by sea; no commodious building; no instruments of moving and removing such things as require much force; no knowledge of the face of the earth; no account of time; no arts; no letters; no society; and which is worst of all, continual fear, and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short. [The Leviathan, 13]

Note

Missionaries, for example, point to the relationship between Christianity and guilt culture:

There is a lack of a sense of sin in African thinking for many reasons: (1) there is a belief that God and the ancestors are unconcerned about private and public morality. People believe more in this life than the next life; (2) there is more of a shame-culture than a guilt-culture. People are more afraid of public opinion than of God; and (3) there is a focus on communal living where people look at who caused a problem. (Tittley, 2001)

See also Lebra (1971) and Carroll (1981).

 

References

Bedingfield, M.D. (2002). The Dramatic Liturgy of Anglo-Saxon England, The Boydell Press. 

Beja-Pereira A., G. Luikart, P.R. England, et al. (2003). Gene-culture coevolution between cattle milk protein genes and human lactase genes, Nature Genetics, 35, 311-313.

http://www.bioquest.org/summer2007/sessionA/ng1263.pdf 

Carroll, J. (1981). The role of guilt in the formation of modern society: England 1350-1800, The British Journal of Sociology, 32, 459-503.

http://www.jstor.org/discover/10.2307/590129?uid=3739448&uid=2&uid=3737720&uid=4&sid=21104745207513 

Frost, P. (2012). On global inequality, Evo and Proud, August 25

http://evoandproud.blogspot.ca/2012/08/on-global-inequality.html

Frantzen, A.J. (1983). The literature of penance in Anglo-Saxon England, New Brunswick (N.J.): Rutgers University Press.

Godden, M.R. (1973). An Old English penitential motif, Anglo-Saxon England, 2, 221-239.

Hobbes, T. (2010). The Leviathan. Peterborough: Broadview Press. 

Lebra, T.S. (1971). The social mechanism of guilt and shame: the Japanese case, Anthropological Quarterly, 44, 241-255.

http://www.jstor.org/discover/10.2307/3316971?uid=3739448&uid=2&uid=3737720&uid=4&sid=21104745207513 

Original Sin. (2014). Wikipedia

http://en.wikipedia.org/wiki/Original_sin 

Peace and Truce of God. (2014). Wikipedia

http://en.wikipedia.org/wiki/Peace_and_Truce_of_God 

Sacrament of Penance. (2014). Wikipedia

http://en.wikipedia.org/wiki/Sacrament_of_Penance_(Catholic_Church)  

Tittley, M. (2001). Book summary of The Primal Vision: Christian Presence amid African Religion, by John V. Taylor, SCM Press, 1963.

http://www.ymresourcer.com/Summaries.php