Monday, February 24, 2020

Between Europe and America

Iceland had pre-Columbian contacts with North America. Did they lead to intermarriage? (Wikicommons)

Did the Norse have sustained contacts with the indigenous peoples of the Americas, including intermarriage? Or was Vinland a fleeting encounter?

Steve Sailer touched on this question in a recent column, citing an Icelandic study. Although Iceland’s gene pool is overwhelmingly from Scandinavia and the British Isles, there are also traces of a lineage normally found among the indigenous peoples of northeast Asia and the Americas. Preliminary genealogical analyses have shown that this lineage was present in Iceland at least 300 years ago. 

This raised the intriguing possibility that the Icelandic C1 lineage could be traced to Viking voyages to the Americas that commenced in the 10th century. In an attempt to shed further light on the entry date of the C1 lineage into the Icelandic mtDNA pool and its geographical origin, we used the deCODE Genetics genealogical database to identify additional matrilineal ancestors that carry the C1 lineage and then sequenced the complete mtDNA genome of 11 contemporary C1 carriers from four different matrilines. Our results indicate a latest possible arrival date in Iceland of just prior to 1700 and a likely arrival date centuries earlier. Most surprisingly, we demonstrate that the Icelandic C1 lineage does not belong to any of the four known Native American (C1b, C1c, and C1d) or Asian (C1a) subclades of haplogroup C1. Rather, it is presently the only known member of a new subclade, C1e. (Ebenesersdóttir et al. 2011)

I doubt the hypothesis of Amerindian admixture. As the authors note, the C1e subclade has not been found in any indigenous population of the Americas. Perhaps this is because those populations have not been studied as thoroughly as the Icelandic one. Perhaps it is present among Amerindians, but at a frequency too low to be detected by studies done to date.

But why, then, do we see no other Amerindian subclades in Icelanders? That population has been studied so exhaustively that even low frequencies of other subclades should have been detected by now. This point is made by Der Sarkissian et al. (2014):

Among other hypotheses including that of a European origin, an American origin was favoured on the basis that most of the hg C1 diversity is found on the American continent, despite the fact that no sequence belonging to hg C1e could be detected in the Americas (or anywhere else). This lack of match was explained by under-sampling of the American mtDNA genome diversity [10]. In any case, if admixture between Native Americans and Vikings did occur, it must have been limited, as no other American-specific lineage (e.g. hg A2, B2, D1, C1b, C1c, C1d) was detected in Iceland.

The authors of the same study point out that a sister subclade, C1f, has been found in human remains from Mesolithic northeast Europe. Moreover, it is not excluded that these two sister subclades, C1e and C1f, still exist in northeast Europe. The Icelandic population has been studied much more than almost any other population, so C1e might still exist somewhere in northeast Europe but hasn't been found because of its low frequency. The authors conclude:

... we suggest that the Icelandic-specific C1e sub-clade could have had a recent origin in northern Europe rather than an American origin. This hypothesis is relevant with regard to the origins of the Icelandic population, as Iceland was discovered and first settled by Scandinavian Vikings around 1,130 years ago. Vikings raids extended as far from their homeland in Scandinavia as France, Spain and Sicily, but their main expansion range comprised western Russia, the Baltic region, Scandinavia, and the British Isles.

In fact, we know that some of Iceland's settlers had trading contacts with Russia and may have had slaves of Slavic origin:

No name given in Landnámabók resembles any Slavic form. But the settlers who came from Sweden and Gotland (e.g. S. 209) must have had various contacts with the Slavs. This would be the case also with some Norwegians who like Skinna-Bjöm 'used to go trading to Novgorod' before he went to Iceland. His son Miðjarðar-Skeggi 'went to plunder in the Baltic' (S. 174 and H. 140). Such people were very likely to have aboard their ships Slavic slaves and/or companions recruited from among southern Baltic pirates or inhabitants of the multiethnic emporia like Wolin/Jómsborg or Truso. (Urbanczyk 2002, p. 160)

A Slavic presence in Iceland is further suggested by the existence of "sunken huts"—rectangular-like depressions in the ground with vertical walls, stone ovens placed in one of the corners, and roof constructions supported by corner posts. To date, the remains of eighteen such huts have been discovered in Iceland, and they seem to date to the settlement period. They are also typically Slavic:

Considering the houses they built there is little alternative to the conclusion that they were Slavs or, at least, people who grew up among the Slavs which made them 'Slavs' culturally. Such houses, distinctively different from the Germanic sunken huts are known in thousands from all the lands settled by early Slavs in Eastern, Southern and Central Europe. (Urbanczyk 2002, p. 163)

It should be pointed out that the Norse were major players in the early medieval slave trade, particularly in supplying North African and Middle Eastern clients with fair-skinned women. One of the largest slave markets was at Hederby, on what is now the Danish-German border. It was largely to cash in on the demand for slaves that the Norse began launching their infamous raids across Europe (Holm 1986; Raffield 2019; Skirda 2010, 143-146). Regular visits by Muslim merchants likely explain the influx of Middle Eastern silver coins into Scandinavia during the ninth and tenth centuries (Raffield 2019). 

Such visits may also explain the presence of low levels of North African ancestry in the Icelandic gene pool. Ásmundsdóttir (2017) argues that this North African ancestry entered the Icelandic gene pool by way of the initial Scandinavian settlers. It may thus have its origins in merchants from Muslim Spain and North Africa who regularly came to trading centers like Hederby.


Ásmundsdóttir R.D. (2017). The African L3e5a haplogroup in the Icelandic population.
Skemman repository of dissertations

Der Sarkissian, C., P. Brotherton, O. Balanovsky, J.E. Templeton, B. Llamas, J. Soubrier, V. Moiseyev, V. Khartanovich, A. Cooper, W. Haak, and Genographic Consortium (2014). Mitochondrial genome sequencing in Mesolithic North East Europe Unearths a new sub-clade within the broadly distributed human haplogroup C1. PloS one 9(2), e87612. 

Ebenesersdóttir, S.S., Á. Sigurðsson, F. Sánchez-Quinto, C. Lalueza-Fox, K. Stefánsson, and A. Helgason, (2011). A new subclade of mtDNA haplogroup C1 found in icelanders: Evidence of pre-columbian contact? American Journal of Physical Anthropology 144: 92-99.

Holm, P. (1986). The Slave trade of Dublin, Ninth to Twelfth Centuries. Peritia 5: 317-45.

Raffield, B. (2019). The Slave Markets of the Viking World: Comparative Perspectives on an 'Invisible Archaeology'. Slavery & Abolition 40(4)

Sailer, S. (2020). Are Any Living Humans Descended from Pre-1492 Trans-Atlantic Contacts? The Unz Review, February 20

Skirda, A. (2010). La traite des Slaves. L'esclavage des Blancs du VIIIe au XVIIIe siècle. Paris: Les Éditions de Paris Max Chaleil.

Urbanczyk, P. (2002). Ethnic aspects of the settlement of Iceland. Collegium medievale: interdisciplinary journal of medieval research 15:155-166

Monday, February 17, 2020

A Pandora's box?

Chinese lung tissue seems to be receptive to coronaviruses, perhaps because frequent mild infections stimulate the immune system to protect against more serious pulmonary infections, like pneumonia and tuberculosis. This may be why China escaped the ravages of the Spanish flu in 1918. Have modern measures for public health opened a Pandora's box in China? (Wikipedia – CDC)

Are Chinese people more vulnerable than others to the Wuhan coronavirus? The question is raised by Zhao et al. (2020), who examined lung tissues from several donors and studied a receptor that acts as the point of entry for some coronaviruses, including the ones responsible for the SARS outbreak of 2002-2003 and the ongoing outbreak in Wuhan, China. They found that the receptor was concentrated in cells that promote viral reproduction and transmission. They also found that the number of these cells in lung tissue varied with ethnic origin:

A comparison between eight individual samples demonstrated that the Asian male one has an extremely large number of ACE2-expressing cells in the lung. We also noticed that the only Asian donor (male) has a much higher ACE2-expressing cell ratio than white and African American donors (2.50% vs. 0.47% of all cells). This might explain the observation that the new Coronavirus pandemic and previous SARS-Cov pandemic are concentrated in the Asian area.

This study is a preprint and has not yet been peer-reviewed, a fact highlighted in a notice placed above the online paper:

bioRxiv is receiving many new papers on coronavirus 2019-nCoV. A reminder: these are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information.

I often consult bioRxiv, and this is the first time I've seen such a notice. It's not as if this study has been widely publicized in the mainstream media.

A peer reviewer would make the same criticism that the authors themselves make: the sample size is small. In fact, there was only one Asian in the entire sample. Nevertheless, sampling error cannot easily explain the five-fold difference between the Asian donor and the non-Asian ones. Moreover, this finding is consistent with those of previous studies. Cheng et al. (2007) looked at other receptors for viral infections and found differences between Chinese and other human populations. In the specific case of pulmonary diseases, Seitz et al. (2012) studied the prevalence of bronchiectasis in the United States and found that Asian Americans had a prevalence 2.5 to 3.9 times higher than those of Euro Americans and African Americans. Kwak et al. (2010) similarly found a high prevalence of bronchiectasis in Korean adults.

These ethnic differences should be no surprise. Many pathogens can infect some populations more easily than others. This was shown by a study of the TLR2 polymorphism, which influences resistance to such infections as leprosy, tuberculosis, staphylococcal infections, and sepsis:

Interestingly, recent data have pointed out that TLR2 polymorphisms are associated with disseminated tuberculosis or exert specific effects on susceptibility to certain mycobacterial strains, such as the Beijing strains of Mycobacterium tuberculosis. The Beijing strains have a clear geographical distribution, raising the possibility that human TLR2 has coevolved in various populations depending on the type of infectious pressure in a particular region, similarly to what has been reported for polymorphisms in other innate immune genes such as TLR4 or Mal/TIRAP. (Iona et al. 2012)

The argument here is that an infectious disease will favor the survival and reproduction of those people who are more resistant to it. So, over succeeding generations, the average person will become naturally more resistant. The degree of resistance will vary from one population to another because the incidence of infectious pathogens typically varies from one population to another.

In this case, the average Chinese person seems to be naturally less resistant to coronaviruses. That is a bit surprising. The Chinese have cohabited with various forms of livestock for a long time, longer than most humans, and should have become more resistant to viral infections that jump the species barrier, like the current coronavirus in Wuhan. Yet, here, the reverse is true.

Perhaps we're looking at this coevolution the wrong way. Perhaps coronaviruses usually do more good than harm. Perhaps, over time, there has been selection to make the average Chinese person less resistant to them. This possibility has been explored in a recent paper by Shekhar et al. (2017). Certain viral infections of the respiratory tract seem to help their hosts by boosting resistance to bacterial infections:

Little is known about the interaction of the host with commensal viruses and fungi that inhabit the respiratory system. Latent infection with herpesviruses can lead to opportunistic infections in immunocompromised individuals. Recent findings, however, highlight a new role for these viruses in increasing host resistance to bacterial infections. Infection with herpesviruses in mice results in chronic production of large quantities of IFN-γ and activation of macrophages that confer protection from subsequent infection with Listeria monocytogenes and Yersinia pestis. (Shekhar et al. 2017)

So you periodically come down with a mild flu, and you can better resist more serious pulmonary infections, like pneumonia and tuberculosis. Of course, now and again, the flu might be deadly, like the one in 1918. Interestingly, China was largely unaffected by the Spanish flu pandemic: "in 1918, China was spared from the worst ravages of the pandemic, due to the apparent greater resistance to the virus among the Chinese population compared to other regions of the world" (Wikipedia 2020).

Since then, public hygiene measures have steadily reduced chronic exposure to mild pulmonary infections in the Chinese population. If the Spanish flu struck China today, would the Chinese people be just as unaffected? Is this why the Wuhan outbreak has been so severe?


The Chinese population has developed a commensal relationship with coronaviruses, which are usually mild and seem to prepare the immune system for serious pulmonary infections. Through a process of coevolution, the Chinese have become five times more susceptible to coronaviruses than other human populations. 

Far from being an enemy, these viruses may actually be a friend that plays a valuable immunological role. By creating a cleaner social environment, the Chinese authorities may have unwittingly opened a Pandora's box. 

As for non-Chinese people, it doesn't follow that they will be immune to the new coronavirus, only that they will be less vulnerable.

On a final note, the economic disruption due to the Wuhan outbreak will lead to a contraction in Chinese production, and this contraction will exacerbate the ongoing problem of China's shrinking workforce. There are going to be fewer and more expensive consumer goods on the global market. Ironically, all of this is happening as we enter the 2020s—a decade already predicted to be a time of crisis. 


Cheng, P-L, H-L. Eng, M-H. Chou, H-L. You, T-M. Lin, (2007). Genetic polymorphisms of viral infection-associated Toll-like receptors in Chinese population. Translational Research 150(5): 311-318 

Ioana, M., B. Ferwerda, T. S. Plantinga, M. Stappers, M. Oosting, M. McCall, A. Cimpoeru, F. Burada, N. Panduru, R. Sauerwein, O. Doumbo, J. W. M. van der Meer, R. van Crevel, L. A. B. Joosten, and M. G. Netea. (2012). Different Patterns of Toll-Like Receptor 2 Polymorphisms in Populations of Various Ethnic and Geographic Origins. Infection and Immunity 80(5): 1917-1922 

Kwak, H.J., J.Y. Moon, Y.W. Choi, T.H. Kim, J.W. Sohn, H.J. Yoon, D.H. Shin, S.S. Park, and S.H. Kim. (2010). High prevalence of bronchiectasis in adults: analysis of CT findings in a health screening program. Tohoku Journal of Experimental Medicine 222: 237-242.

Seitz, A.E., K.N. Olivier, J. Adjemian, S.M. Holland, and D.R. Prevots. (2012). Trends in bronchiectasis among medicare beneficiaries in the United States, 2000 to 2007. Chest 142(2):432-439.

Shekhar, S., K. Schenck, and F. C. Petersen (2017). Exploring Host-Commensal Interactions in the Respiratory Tract. Frontiers in Immunology 8: 1971  

Wikipedia. (2020). Spanish flu 

Zhao, Y., Z. Zhao, Y. Wang, Y. Zhou, Y. Ma, and W. Zuo. (2020). Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov. bioRxiv January 26