Showing posts with label East Asia. Show all posts
Showing posts with label East Asia. Show all posts

August 21, 2016

Mitochondrial DNA of ancient Tocharians

Quickies

It seems there is still something to learn about the ancient Tocharian mummies of Uyghuristan:

Chunxiang Li et al., Analysis of ancient human mitochondrial DNA from the Xiaohe cemetery: insights into prehistoric population movements in the Tarim Basin, China. BMC Genetics 2016. Open accessLINK [doi:10.1186/s12863-015-0237-5]

Abstract

Background

The Tarim Basin in western China, known for its amazingly well-preserved mummies, has been for thousands of years an important crossroad between the eastern and western parts of Eurasia. Despite its key position in communications and migration, and highly diverse peoples, languages and cultures, its prehistory is poorly understood. To shed light on the origin of the populations of the Tarim Basin, we analysed mitochondrial DNA polymorphisms in human skeletal remains excavated from the Xiaohe cemetery, used by the local community between 4000 and 3500 years before present, and possibly representing some of the earliest settlers.

Results

Xiaohe people carried a wide variety of maternal lineages, including West Eurasian lineages H, K, U5, U7, U2e, T, R*, East Eurasian lineages B, C4, C5, D, G2a and Indian lineage M5.

Conclusion

Our results indicate that the people of the Tarim Basin had a diverse maternal ancestry, with origins in Europe, central/eastern Siberia and southern/western Asia. These findings, together with information on the cultural context of the Xiaohe cemetery, can be used to test contrasting hypotheses of route of settlement into the Tarim Basin.


February 14, 2016

Neolithic East Asians tamed leopard cats

Quickies

Leopard cat
(CC: F. Spangenberg - Der Irbis)
It's hard to say that cats are domestic at all, tamed is probably a better concept. Some would of course argue that it is cats who have tamed us humans, debatable I guess.

In any case this relationship has not been restricted to the common cat (Felis silvestris catus) but it has been known now that ancient East Asians managed to establish the same kind of relationship with a local feline of similar characteristics: the leopard cat (Prionailurus bengalensis). However at some point the Western cat took over and nothing remains of that ancient domestication event.

Jean-Denis Vigne et al., Earliest “Domestic” Cats in China Identified as Leopard Cat (Prionailurus bengalensis). PLoS ONE 2015. Open access → LINK [doi:10.1371/journal.pone.0147295]

Abstract

The ancestor of all modern domestic cats is the wildcat, Felis silvestris lybica, with archaeological evidence indicating it was domesticated as early as 10,000 years ago in South-West Asia. A recent study, however, claims that cat domestication also occurred in China some 5,000 years ago and involved the same wildcat ancestor (F. silvestris). The application of geometric morphometric analyses to ancient small felid bones from China dating between 5,500 to 4,900 BP, instead reveal these and other remains to be that of the leopard cat (Prionailurus bengalensis). These data clearly indicate that the origins of a human-cat ‘domestic’ relationship in Neolithic China began independently from South-West Asia and involved a different wild felid species altogether. The leopard cat’s ‘domestic’ status, however, appears to have been short-lived—its apparent subsequent replacement shown by the fact that today all domestic cats in China are genetically related to F. silvestris.

October 28, 2015

Ainu genetics in their geographical context

Quickies

Timothy A. Jinam et al., Unique characteristics of the Ainu population in Northern Japan. Journal of Human Genetics 2015. Open access → LINK [doi:10.1038/jhg.2015.79]

Abstract

Various genetic data (classic markers, mitochondrial DNAs, Y chromosomes and genome-wide single-nucleotide polymorphisms (SNPs)) have confirmed the coexistence of three major human populations on the Japanese Archipelago: Ainu in Hokkaido, Ryukyuans in the Southern Islands and Mainland Japanese. We compared genome-wide SNP data of the Ainu, Ryukyuans and Mainland Japanese, and found the following results: (1) the Ainu are genetically different from Mainland Japanese living in Tohoku, the northern part of Honshu Island; (2) using Ainu as descendants of the Jomon people and continental Asians (Han Chinese, Koreans) as descendants of Yayoi people, the proportion of Jomon genetic component in Mainland Japanese was ~18% and ~28% in Ryukyuans; (3) the time since admixture for Mainland Japanese ranged from 55 to 58 generations ago, and 43 to 44 generations ago for the Ryukyuans, depending on the number of Ainu individuals with varying rates of recent admixture with Mainland Japanese; (4) estimated haplotypes of some Ainu individuals suggested relatively long-term admixture with Mainland Japanese; and (5) highly differentiated genomic regions between Ainu and Mainland Japanese included EDAR and COL7A1 gene regions, which were shown to influence macroscopic phenotypes. These results clearly demonstrate the unique status of the Ainu and Ryukyuan people within East Asia.

Figure 1. Principal component analysis (PCA) plot after omitting closely related Ainu individuals.

The study detected some differences between Ainu and other East Asians in genes that produce differences in appearance, these are:
Two out of five genes for facial morphology (PAX3 and COL17A1) contain highly differentiated SNPs, as with the hair/tooth morphology gene (EDAR).

October 15, 2015

More evidence supporting very old colonization of Asia by H. sapiens

Quickies

Quite worth mentioning:

Wu Liu et al., The earliest unequivocally modern humans in southern China. Nature 2015. Pay per viewLINK [doi:10.1038/nature15696]

Abstract

The hominin record from southern Asia for the early Late Pleistocene epoch is scarce. Well-dated and well-preserved fossils older than ~45,000 years that can be unequivocally attributed to Homo sapiens are lacking1, 2, 3, 4. Here we present evidence from the newly excavated Fuyan Cave in Daoxian (southern China). This site has provided 47 human teeth dated to more than 80,000 years old, and with an inferred maximum age of 120,000 years. The morphological and metric assessment of this sample supports its unequivocal assignment to H. sapiens. The Daoxian sample is more derived than any other anatomically modern humans, resembling middle-to-late Late Pleistocene specimens and even contemporary humans. Our study shows that fully modern morphologies were present in southern China 30,000–70,000 years earlier than in the Levant and Europe. Our data fill a chronological and geographical gap that is relevant for understanding when H. sapiens first appeared in southern Asia. The Daoxian teeth also support the hypothesis that during the same period, southern China was inhabited by more derived populations than central and northern China. This evidence is important for the study of dispersal routes of modern humans. Finally, our results are relevant to exploring the reasons for the relatively late entry of H. sapiens into Europe. Some studies have investigated how the competition with H. sapiens may have caused Neanderthals’ extinction (see ref. 8 and references therein). Notably, although fully modern humans were already present in southern China at least as early as ~80,000 years ago, there is no evidence that they entered Europe before ~45,000 years ago. This could indicate that H. neanderthalensis was indeed an additional ecological barrier for modern humans, who could only enter Europe when the demise of Neanderthals had already started.

When asked in private correspondence earlier today what did I think of this, I replied that María Martinón (second listed author) is a top expert in tooth morphology and that, if she says they are unmistakably H. sapiens, I have to believe it. 

I also replied a bit more extensively that this should be no surprise, that evidence in favor of a c. 100 Ka BP migration of H. sapiens into South and Southeast Asia has been piling up for some time already. Some of the most important pieces of evidence are the Zhirendong jaw (also from Southern China, dated to c. 100 Ka BP) and the African-like Katoati toolkits (NW India, dated to c. 96 Ka BP). These dates are roughly coincident with the end of the Abbassia Pluvial (c. 125-90 Ka BP), which is in turn coincident with the period of evidence for earliest H. sapiens presence in Arabia and Palestine. 

In other words, our ancestors crossed into Arabia and Palestine (and maybe other less well documented nearby regions of West Asia) around 125 millennia ago (with a second wave c. 90 Ka ago). The Neanderthal admixture episode probably happened soon after. Then they moved to South and SE Asia, quite possibly pressed by growingly arid conditions in Arabia, and this second migration took place around 100 millennia ago (earlier is not yet supported but can't be fully discarded). 

All this has major implications for molecular clock calibration, of course: mtDNA L3 should be c. 125 Ka old and M some 100 Ka old, similarly Y-DNA CF should be around 100 Ka old as well. This is the kind of stuff that makes genetics-oriented people skeptic but the molecular clock is a mere educated hunch, while the archaeological data is serious evidence that cannot be ignored.

August 22, 2015

Tarim Basin mtDNA

Quantity over quality series.

Chuxian Li et al. Analysis of ancient human mitochondrial DNA from the Xiaohe cemetery: insights into prehistoric population movements in the Tarim Basin, China. BMC Genetics 2015. Open accessLINK. [doi:10.1186/s12863-015-0237-5]

Abstract

Background

The Tarim Basin in western China, known for its amazingly well-preserved mummies, has been for thousands of years an important crossroad between the eastern and western parts of Eurasia. Despite its key position in communications and migration, and highly diverse peoples, languages and cultures, its prehistory is poorly understood. To shed light on the origin of the populations of the Tarim Basin, we analysed mitochondrial DNA polymorphisms in human skeletal remains excavated from the Xiaohe cemetery, used by the local community between 4000 and 3500 years before present, and possibly representing some of the earliest settlers.

Results

Xiaohe people carried a wide variety of maternal lineages, including West Eurasian lineages H, K, U5, U7, U2e, T, R*, East Eurasian lineages B, C4, C5, D, G2a and Indian lineage M5.

Conclusion

Our results indicate that the people of the Tarim Basin had a diverse maternal ancestry, with origins in Europe, central/eastern Siberia and southern/western Asia. These findings, together with information on the cultural context of the Xiaohe cemetery, can be used to test contrasting hypotheses of route of settlement into the Tarim Basin.

Note: R* is not "Western" but undefined and quite possibly Eastern.

July 8, 2015

Zipf's law against 'Genghis Khan' sensationalism

Very interesting new short paper at BioRxiv:

Elsa G. Guillot & Murray P. Cox, High Frequency Haplotypes are Expected Events, not Historical Figures. BioRxiv 2015 (pre-pub, freely accessible) → LINK [doi: http://dx.doi.org/10.1101/022160]

Abstract

Cultural transmission of reproductive success states that successful men have more children and pass this greater fecundity to their offspring. Balaresque and colleagues found high frequency haplotypes in a Central Asian Y chromosome dataset, which they attribute to cultural transmission of reproductive success by prominent historical men, including Genghis Khan. Using coalescent simulation, we show that these high frequency haplotypes are expected simply by chance. Hence, an explanation invoking cultural transmission of reproductive success is statistically unnecessary.


Not surprisingly it is, once again, the hyper-sensationalist, hyper-recentist, over-simplifying and evidence cherry-picker geneticist Patricia Balaresque who is the object of these very legitimate criticisms.

The basic argument is very simple: in neutrality conditions haplotype distributions follow Zipf's power law, while a single-founder effect of the type of the alleged Genghis Khan one would never cause that: one lineage would be outstanding, while the rest would show no hierarchy. 

However the authors, to make their argument even more certain, simulated genetic data under the standard coalescent, a neutral model that does not include cultural transmission of reproductive success. As you can expect, the simulations confirmed that what surprised Balaresque and others is just absolutely normal by mere chance: no Genghis Khan effect ever took place.

May 18, 2014

Siberian genetics with focus on Yakutia

Informative study on the populations of Sakha Republic (Yakutia) and Siberia in general:

Sardana A. Fedorova et al., Autosomal and uniparental portraits of the native populations of Sakha (Yakutia): implications for the peopling of Northeast Eurasia. BMC Evolutionary Biology 2014. Open accessLINK [doi:10.1186/1471-2148-13-127]

Abstract

Background

Sakha – an area connecting South and Northeast Siberia – is significant for understanding the history of peopling of Northeast Eurasia and the Americas. Previous studies have shown a genetic contiguity between Siberia and East Asia and the key role of South Siberia in the colonization of Siberia.

Results

We report the results of a high-resolution phylogenetic analysis of 701 mtDNAs and 318 Y chromosomes from five native populations of Sakha (Yakuts, Evenks, Evens, Yukaghirs and Dolgans) and of the analysis of more than 500,000 autosomal SNPs of 758 individuals from 55 populations, including 40 previously unpublished samples from Siberia. Phylogenetically terminal clades of East Asian mtDNA haplogroups C and D and Y-chromosome haplogroups N1c, N1b and C3, constituting the core of the gene pool of the native populations from Sakha, connect Sakha and South Siberia. Analysis of autosomal SNP data confirms the genetic continuity between Sakha and South Siberia. Maternal lineages D5a2a2, C4a1c, C4a2, C5b1b and the Yakut-specific STR sub-clade of Y-chromosome haplogroup N1c can be linked to a migration of Yakut ancestors, while the paternal lineage C3c was most likely carried to Sakha by the expansion of the Tungusic people. MtDNA haplogroups Z1a1b and Z1a3, present in Yukaghirs, Evens and Dolgans, show traces of different and probably more ancient migration(s). Analysis of both haploid loci and autosomal SNP data revealed only minor genetic components shared between Sakha and the extreme Northeast Siberia. Although the major part of West Eurasian maternal and paternal lineages in Sakha could originate from recent admixture with East Europeans, mtDNA haplogroups H8, H20a and HV1a1a, as well as Y-chromosome haplogroup J, more probably reflect an ancient gene flow from West Eurasia through Central Asia and South Siberia.

Conclusions

Our high-resolution phylogenetic dissection of mtDNA and Y-chromosome haplogroups as well as analysis of autosomal SNP data suggests that Sakha was colonized by repeated expansions from South Siberia with minor gene flow from the Lower Amur/Southern Okhotsk region and/or Kamchatka. The minor West Eurasian component in Sakha attests to both recent and ongoing admixture with East Europeans and an ancient gene flow from West Eurasia.

The matrilineal mitochondrial DNA pool is dominated by  C4, C5, D4 and D5, with some instances of other lineages (see fig. 1). All these and most of the rest are common Siberian lineages of East Asian roots. 

In the odd zone, the extremely rare haplogroup R3 has been found among North Yuhaghirs in this study (previously only in Jordan that I know with any certainty). They mention that R3 and R1 are derived from the same root, sharing two coding region mutations, and therefore they proceed to rename R3 as R1b. R1 is an also rare Indian matrilineage. 

The patrilineal Y-DNA pool (see fig. 2) is massively dominated by N1c, which also dominates most Uralic-speaking peoples. This is unusual for a Turkic-speaking population but it was known since long ago. Other still important lineages are C2 (former C3, typical of NE Asia and some North American populations), N1b and R1a. Some instances of I, E1b1b1, J, O, F and L are also reported. C2 is more important among the Northern (non-Turkic) populations of Sakha Republic, reaching to 30-40%.

On the autosomal DNA pool, the heatmat (fig. 4) shows that among all sampled populations the Selkup are particularly isolated. Koryaks and Chukchis from the far NE Siberia form a small cluster of their own and so do Shors and Kets (West Siberians). Native American populations also show great individual isolation in comparison with most Eurasians.

Otherwise there are three major clusters: West/South/Central Eurasians, East Asians and Siberians, who generally also cluster with East Asians.

Some of this is also apparent in the PCA (fig. 5) although not as neatly:

PCA of the native populations of Sakha in the context of other Eurasian and American populations.

Maybe more illustrative is the ADMIXTURE analysis:

ADMIXTURE plots. Ancestry proportions of the 758 individuals studied (from 55 populations) as revealed by the ADMIXTURE software at K = 3, K = 4, K = 6, K = 8, and K = 13.
The analysis reveals, from K=6 upwards, the following clusters: West Eurasian (dark blue), South Asian (green), East Asian (orange, also light green at K=13) and several Siberian and Native American specific clusters (yellow, light and dark brown, red, etc.)

The persistance of the blue West Eurasian component in Aleutians and Greenlanders should raise some eyebrows. However, Greenlanders do not really cluster with West Eurasians in the heatmap, so this is almost certainly an artifact that indicates that a much greater K-depth should be achieved in order to properly classify this most diverse human sample. Thirteen clusters are obviously not enough.

February 17, 2014

Oldest Okinawan Paleolithic evidence of human presence

A human tooth accompanying a hoard of modified shells shaped as tools have been found in the Sakitari-do cave (Nanjo, Okinawa). They are dated to c. 20-23,000 years ago. They seem to be the first known evidence of human presence in the East Asian archipelago.



The Sakitari-do cave is just 1.5 km away from where the Minatogawa human remains were found, which are however of a somewhat more recent date (c. 18-16 Ka ago). 

Minatogawa 1 (source)

Source: The Asahi Shimbun (via Pileta).

February 16, 2014

Ancient DNA from Clovis culture is Native American (also Tianyuan affinity mystery)

Figure 4 | [c] (...) maximum likelihood tree. 
A recent study on the ancient DNA of human remains from Anzick (Montana, USA), dated to c. 12,500 calBP, confirms close ties to modern Native Americans, definitely discarding the far-fetched and outlandishly Eurocentric "Solutrean hypothesis" for the origins of Clovis culture (what pleases me greatly, I must admit).

While this fits well with the expectations (at least mine), there is some hidden data that has surprised me quite a bit: it sits at the bottom of a non-discussed formal test graph in which modern populations are compared with both Anzick and Tianyuan (c. 40,000 BP, North China). See below.

Morten Rasmussen et al., The genome of a Late Pleistocene human from a Clovis burial site in western Montana. Nature 2014. Pay per viewLINK [doi:10.1038/nature13025]

Abstract

Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 14C years before present (bp) (13,000 to 12,600 calendar years bp)1, 2. Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the North American ice sheets from an ancestral technology3. However, both the origins and the genetic legacy of the people who manufactured Clovis tools remain under debate. It is generally believed that these people ultimately derived from Asia and were directly related to contemporary Native Americans2. An alternative, Solutrean, hypothesis posits that the Clovis predecessors emigrated from southwestern Europe during the Last Glacial Maximum4. Here we report the genome sequence of a male infant (Anzick-1) recovered from the Anzick burial site in western Montana. The human bones date to 10,705 ± 35 14C years bp (approximately 12,707–12,556 calendar years bp) and were directly associated with Clovis tools. We sequenced the genome to an average depth of 14.4× and show that the gene flow from the Siberian Upper Palaeolithic Mal’ta population5 into Native American ancestors is also shared by the Anzick-1 individual and thus happened before 12,600 years bp. We also show that the Anzick-1 individual is more closely related to all indigenous American populations than to any other group. Our data are compatible with the hypothesis that Anzick-1 belonged to a population directly ancestral to many contemporary Native Americans. Finally, we find evidence of a deep divergence in Native American populations that predates the Anzick-1 individual.


Haploid DNA

The Y-DNA lineage of Anzick is Q1a2a1* (L54) to the exclusion of the common Native American subhaplogroup Q1a2a1a1 (M3). Among the modern compared sequences that of a Maya is the closest one.

The mtDNA belongs to the common Native American lineage D4h3a at its underived stage (root). 

For starters I must explain that these underived haplotypes can only be found within mtDNA and never in modern Y-DNA (common misconception) because this one accumulates mutations every single generation, while the much shorter mtDNA does only occasionally. Hypothetically we could find the exact ancestor of some modern Y-DNA haplogroup in ancient remains but that would be like finding the proverbial needle in the haystack. On the other hand, finding the underived stage in mtDNA, be it ancient or modern, does not mean that we are before a direct ancestor but just a non-mutated relative of her, who can be very distant in fact.


Autosomal DNA

In this aspect, the Anzick man shows clearly strongest affinities to Native Americans, followed at some distance by Siberian peoples, particularly those near the Bering Strait. 

Figure 2 | Genetic affinity of Anzick-1. a, Anzick-1 is most closely related to Native Americans. Heat map representing estimated outgroup f3-statistics for shared genetic history between the Anzick-1 individual and each of 143 contemporary human populations outside sub-Saharan Africa. (...)

However Anzick-1 shows clearly closer affinity to the aboriginal peoples of Meso, Central and South America (collectively labeled as SA) and less so to those of Canada and the American Arctic (labeled as NA). No data was available from the USA. 

This was pondered by the authors in several competing models of Native American ancestry:

Figure 3 | Simplified schematic of genetic models. Alternative models of the population history behind the closer shared ancestry of the Anzick-1 individual to Central and Southern American (SA) populations than Northern Native American (NA) populations; seemain text for further definition of populations. We find that the data are consistent with a simple tree-like model in which NA populations are historically basal to Anzick-1 and SA. We base this conclusion on two D-tests conducted on the Anzick-1 individual, NA and SA. We used Han Chinese as outgroup. a, We first tested the hypothesis that Anzick-1 is basal to both NA and SA populations using D(Han, Anzick-1; NA, SA). As in the results for each pairwise comparison between SA and NA populations (Extended Data Fig. 4), this hypothesis is rejected. b, Next, we tested D(Han, NA; Anzick-1, SA); if NA populations were a mixture of post-Anzick-1 and pre-Anzick-1 ancestry, we would expect to reject this topology. c, We found that a topology with NA populations basal to Anzick-1 and SA populations is consistent with the data. d, However, another alternative is that the Anzick-1 individual is from the time of the last common ancestral population of the Northern and Southern lineage, after which the Northern lineage received gene flow from a more basal lineage.

The most plausible model they believe is "c", in which Anzick-1 is close to the origin of the SA population, while NA diverged before him. However model "d" in which Anzick-1 is close to the overall Native American root but NA have received further inputs from a mystery population (presumably some Siberians, related to the Na-Dené and Inuit waves) is also consistent with the data. Choosing between both "consistent" models (or something in between) clearly requires further investigation. 



Tianyuan and East Asian origins

All the above is very much within expectations, although refreshingly clarifying. But there is something in the formal tests (extended data fig. 5) that is most unexpected (but not discussed in the paper). 

The formal f3 tests of ED-fig.5 a to e fall all within reasonable expectations. Maybe the most notable finding is that, after all, the pre-Inuit people of the Dorset culture (represented by the Saqqaq remains) left some legacy in Greenland, but they also show some extra affinity with several Siberian populations (notably the Naukan, Chukchi, Koryak and Yukaghir, in this order) before to any other Native Americans, including Aleuts). 

But the really striking stuff is in figs. f and g, where it becomes obvious that the Tianyuan remains of Northern China show not a tad of greater affinity to East Asians (nor to Native Americans) than to West Eurasians. Also two East Asian populations (Tujia and Oroqen) are considerably more distant than the bulk of East Asian peoples to Tianyuan but also to Aznick.

Extended Data Figure 5 | Outgroup f3-statistics contrasted for different combinations of populations. (...) f, g, Shared genetic history with Anzick-1 compared to shared genetic history with the 40,000-year-old Tianyuan individual from China.

This is very difficult to explain, more so as Tianyuan's mtDNA haplogroup B4'5 is part of the East Asian and Native American genetic pool, and the authors make no attempt to do it. 

The previous study by Qiaomei Fu et al. (open access) placed Tianyuan's autosomal DNA near the very root of Circum-Pacific populations (East Asians, Native Americans and Australasian Aborigines) but after divergence from West Eurasians:

From Qiaomei Fu 2013


They even had doubts about the position of Papuans (the only Australasian representation) in that tree, which they suspected an artifact of some sort.

Since I saw that graph (h/t to an anonymous commenter at Fennoscandian Ancestry) I am squeezing my brain trying to figure out a reasonable explanation, considering that the formal f3 test has almost certainly more weight than the ML tree made with an algorithm. 

My first tentative explanation would be to imagine a shared triple-branch origin for Tianyuan, East Asians and West Eurasians, maybe c. 60 Ka ago (it must have been before the colonization of West Eurasia), to the exclusion of other, maybe isolated, ancient populations, whose admixture with the ancestors of the Tujia, Oroqen and Melanesians (maybe via Austronesians?) causes those striking low affinity values for these.

This would be a similar mechanism to the one explaining lower Tianyuan (and generally all ancient Eurasian) affinity for Palestinians (incl. Negev Bedouins) and also the Makrani, who have some African admixture and (in the Palestinian case) also, most likely, residual inputs from the remains of the first Out-of-Africa episode in Arabia.

However to this day we have no idea of which could be those hypothetical ancient isolated populations of East Asia. In normal comparisons such as ADMIXTURE analysis the Tujia and Oroqen appear totally normal within their geographic context, but this may be an artifact of not doing enough runs to reach higher K values, according to the cross-validation test, much more likely to discern the actual realistic components. 

The matter certainly requires further research, which may well open new avenues for the understanding the genesis of Eurasian populations, particularly those from the East.

February 7, 2014

Mitochondrial lineages from Myanmar

Myanmar, also known as Burma, has been one of those blind spots in the mapping of human genetics. Finally now we get to know something about the peoples of this SE Asian multiethnic state, although there are limitations because the sampling was performed among refugees in Thailand.

Monica Summerer et al., Large-scale mitochondrial DNA analysis in Southeast Asia reveals evolutionary effects of cultural isolation in the multi-ethnic population of Myanmar. BMC Evolutionary Biology 2014. Open accessLINK [doi:10.1186/1471-2148-14-17]

Abstract

Background

Myanmar is the largest country in mainland Southeast Asia with a population of 55 million people subdivided into more than 100 ethnic groups. Ruled by changing kingdoms and dynasties and lying on the trade route between India and China, Myanmar was influenced by numerous cultures. Since its independence from British occupation, tensions between the ruling Bamar and ethnic minorities increased.

Results

Our aim was to search for genetic footprints of Myanmar’s geographic, historic and sociocultural characteristics and to contribute to the picture of human colonization by describing and dating of new mitochondrial DNA (mtDNA) haplogroups. Therefore, we sequenced the mtDNA control region of 327 unrelated donors and the complete mitochondrial genome of 44 selected individuals according to highest quality standards.

Conclusion

Phylogenetic analyses of the entire mtDNA genomes uncovered eight new haplogroups and three unclassified basal M-lineages. The multi-ethnic population and the complex history of Myanmar were reflected in its mtDNA heterogeneity. Population genetic analyses of Burmese control region sequences combined with population data from neighboring countries revealed that the Myanmar haplogroup distribution showed a typical Southeast Asian pattern, but also Northeast Asian and Indian influences. The population structure of the extraordinarily diverse Bamar differed from that of the Karen people who displayed signs of genetic isolation. Migration analyses indicated a considerable genetic exchange with an overall positive migration balance from Myanmar to neighboring countries. Age estimates of the newly described haplogroups point to the existence of evolutionary windows where climatic and cultural changes gave rise to mitochondrial haplogroup diversification in Asia.

The main sampled ethnic group are the Karen, who live at the border with Thailand, but the Bamar or Burmans, the largest ethnic group, were also sampled in big numbers. 

Fig. 2.- Origin of samples and mitochondrial haplogroup distribution of Southeast Asian populations. Although most of the study participants originated from Karen State (red), a broad sample spectrum from nearly all divisions and states of Myanmar (a) was included in this study. b shows the haplogroup distributions of populations from Myanmar and four other Southeast Asian regions. In the white insert box the haplogroup heterogeneity of two ethnic groups of Myanmar is illustrated. The hatched area in the map surrounding the border between Myanmar and Thailand shows the main population area of the Karen people. The Bamar represent the largest ethnic group (68%) in Myanmar. The size of the pie diagrams corresponds to sample size.

The smaller samples are only detailed in the supplementary data for what I have seen, so I will not discuss them right now (maybe in an update?). 

Overall all SE Asians including the Southern Han from Hong-Kong appear similar in broad terms. Excepted Laos, this relative similitude is quite apparent in figure 3:

Fig. 3.- Multi-dimensional scaling plot of pairwise Fst-values and haplogroup distribution of populations from Myanmar and 12 other Asian regions. A distinct geographic pattern appeared in the multi-dimensional scaling plot (Stress = 0.086; R2 = 0.970) of pairwise Fst-values: The Myanmar sample fitted very well within the Southeast Asian cluster, the Central Asian populations formed a second cluster, the Korean sample represented East Asia, the Afghanistan population was representative for South Asia and Russia symbolized Western Eurasia. The main haplogroup distributions are displayed as pie charts. The size of the pie diagrams corresponds to sample size. The proportion of N-lineages (without A,B and R9’F) increases from very low percentages in Southeast and East Asia over 50% in Central Asia to more than 75% in Afghanistan and 100% in the sample of Russian origin. The proportion of the American founding haplogroups A,B,C and D displayed an interesting pattern: from inexistent in Russians it increased to more than 50% in East Asian Korea.

Looking at the particular differences in haplogroup frequencies, I'd say that the Thai are quite unremarkable, while the other populations show some peculiarities:
  • Karen: higher frequencies of R9/F, A, C and G
  • Bamar: much higher M* (and extremely diverse)
  • Laotian: higher frequencies of B and M7
  • Vietnamese: more B and N*
  • South Han (Hong-Kong): more D

It is very notable the high diversity of paragroup M* among the Bamar. The authors notice that not more than three individuals shared each different subhaplogroup, what points to a very high diversity within haplogroup M. I don't have time right now to ponder the various lineages, some of which are newly described, but I probably will in the future, because, together with the high diversity in NE India, they have the potential of shifting the paradigm of Asian colonization by H. sapiens a bit towards the East.

The various M* and other novel haplogroups described in Myanmar is shown in fig. 4. Haplogroups M90 and M91 are new basal M sublineages, along with three other unnamed private lineages, which also appear as basal. Also M20a, M49a and G2b1a are new sublineages further downstream. Within N/R, another newly described lineage is B6a1.

The Bamar are extremely diverse not just within M*:
... the haplogroup composition of Bamar was exceptionally diverse with 80 different haplogroups and a maximum of 6 samples in the same haplogroup (Figure 4).

On the other hand, the Karen show the signs of genetic isolation instead, with large concentrations in the same haplogroups.

Interestingly, the authors think that rather than being a receiver, Myanmar was a major source of population to its neighbors:
Migration analyses of Myanmar and four Southeast Asian regions displayed a vivid exchange of genetic material between the countries and demonstrated a strong outwards migration of Myanmar to all analyzed neighboring regions (for details see Additional file 4: Table S4).

This influence is most intense to Laos, Thailand and South China, while things are more balanced regarding Vietnam instead.

December 21, 2013

Siberian haploid DNA

A new study is available with plenty of data on the haploid genetics of Siberian populations with focus on Tungusic peoples.

Anna T. Duggan et al., Investigating the Prehistory of Tungusic Peoples of Siberia and the Amur-Ussuri Region with Complete mtDNA Genome Sequences and Y-chromosomal Markers. PLoS ONE 2013. Open accessLINK [doi:10.1371/journal.pone.0081605]

Maybe the most informative graphic is fig. 1, which shows the scatter of mitochondrial DNA:

Figure 1. Map of Siberia showing approximate locations of sampled populations and their basic haplogroup composition.

For the meaning of abbreviations, check table 1.

Typical NE Asian haplogroups like C and D are quite widely distributed, up to the point of becoming difficult to say much about them. Instead A is more concentrated (Nyukhza, Iengra, both of them Evenks, and Koryaks particularly), while Z does appear to show a similar pattern (but with presence among Kamchatka instead of Koryaks and a relevant distributon in NE Siberia (Berezovka and some Yakuts). 

Haplogroup B is rare instead, only showing up in Southern Yakuts. It must be mentioned in any case because of its relevance in the original peopling of America. 

G is not too common, with the partial exception of G1, which shows an Eastern Siberian concentration.

Y is concentrated among Nivkhs (no surprises here), while F seems most important in Yakutia (like B, it is not a typical Northern lineage but its bulk distribution lays further South).

West Eurasian lineages, marked in Brown are concentrated in the Evens of Nyukhza, as well as among some Yakuts. Their presence among Yakuts is easy to understand considering their partial Turkic ancestry but the Nyukhza even larger apportion seems to me derived of some other kind of contact with Altai and the steppe, although the authors seem to favor Yakut admixture instead.



Premonitory FAQ: 

Which is the difference between "M_N" and "Other"? 

No idea: ask the authors. But I'm quite positive that "Other" cannot mean L(xM,N) but rather "other M and N". Speculatively, it could indicate the difference between some M and N sublineages they have tested for and others which they did not. It's sloppy nomenclature in any case.



Y-DNA

[Important post-script note: excepted the basal SNP markers for C and N, which were tested for, all the haplogroups are defined based on STR markers, what may be wrong].

Table 4 lists the Y-DNA haplogroups for Evenks, Evens, Yakuts and Yukaghirs only. C3c1 is very dominant in the Tungusic populations: 87/127 among Evenks, 43/89 among Evens, but all the opposite among Yakuts (1/184) and rather weak also among Yukaghirs (2/13).

Yakuts are dominated by N1c (173/184), lineage that has also some presence among the other sampled populations: Evenks: 18/127 (Nyukhza and Iengra groups), Evens: 30/89 (particularly Sakkyryyr and Sebjan groups), Yukaghir: 4/13.

Q1 is found mostly among Yukaghirs (4/13) with a single Yakut other case.

N1b is also of some importance among Tungusic peoples: 18/127 among Evenks (Taimyr and Stony Tunguska) and 13/89 among Evens (essentially in Tompo).

C3* is found mostly among Nyukhza Evens (13/78), who also harbor most of the Western lineage I detected in the area (4/78). 

The other meaningful Western lineage spotted is, of course, R1a, which is found in two variants: R1a(xR1a1) is concentrated among Taimyr Evenks (3/18) with only another sample among Stony Tunguska Evenks (1/40). R1a1 instead is concentrated among Yakuts (4/184).

There are also erratics (isolated single-individual samples) of C*, J2, O and F*.


There is also other interesting material in the study but I can only extend myself so much. I strongly recommend reading it for everyone with interest in Siberian and related populations, be these Uralics, Native Americans or generally East and Central Asians.

December 15, 2013

Ancient East Asian Y-DNA maps

I'm fusing here data from two different and complementary sources:
  • Hui Li et al. Y chromosomes of prehistoric people along the Yangtze River. Human Genetics 2007. → LINK (PDF) [doi:10.1007/s00439-007-0407-2]
  • A 2012 study integrally in Chinese (so integrally that I don't even know who the authors are → LINK) but whose content was discussed in English (after synthetic translation) at Eurogenes blog. I deals with a variety of ancient Y-DNA from the Northern parts of P.R. China.

Update (Dec 25): much of the Northeastern aDNA is also discussed in an English language study (h/t Kristiina):

Yinqiu Cui et al. Y Chromosome analysis of prehistoric human populations in the West Liao River Valley, Northeast China. BMC 2013. Open access LINK [doi:10.1186/1471-2148-13-216]


    Combining the data from both sources, I produced the following maps:


    Neolithic (before ~4000 BP):



    Metal Ages (after ~4000 BP):



    Discussion

    I find particularly interesting the first map because it outlines what seem to be three distinct ethnic (or at the very least genetic) regions in the Neolithic period:
    • A Central-South region dominated by O3
    • An Eastern area around modern Shanghai dominated by O1
    • A Northern region dominated by N
    Later on, in the Metal Ages, a colonization of the North/NE by these O3 peoples seems apparent, followed, probably at a later time, by a colonization of the West (Taojiazhai).

    We do not have so ancient data for the West but we can still see a diversity of lineages, notably Q (largely Q1, if not all), C (most likely C3, also in the NE) and N (also in the NE). While the arrival of O3 to this area was probably late, the arrival of R1a1a is quite old, however it is still almost certainly related to the first Indoeuropean migrations eastwards, which founded the Afanasevo culture in the area of Altai.

    I find also very interesting the presence, with local dominance often, of N (including an instance of N1c) and Q in the Northern parts of P.R. China, because these lineages are now rather uncommon but are still dominant in Northern Asia, Northeastern Europe and Native America. The fact that they were still so important in the Northern Chinese frontier in the Neolithic and even in the Metal Ages should tell us something about their respective histories and, in the case of N, origins as well.

    It is also notable that no D was detected anywhere. However the regions with greatest D frequencies like Tibet, Yunnan or Japan were not studied.


    December 2, 2013

    The Mal'ta aDNA findings

    The recent sequencing of ancient DNA from the remains of a Central Siberian young boy, corresponding to the Gravettian site of Mal'ta, West of Lake Baikal, dated to c. 24,000 years calBP, has caught the interest of many anthropology enthusiasts. During my hiatus of more than two months, most people who asked me to retake blogging with an specific request, talked of these findings. Let's see:

    Maanasa Raghavan et al., Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans. Nature 2013. Pay per viewLINK [doi:10.1038/nature12736]

    Abstract

    The origins of the First Americans remain contentious. Although Native Americans seem to be genetically most closely related to east Asians1, 2, 3, there is no consensus with regard to which specific Old World populations they are closest to4, 5, 6, 7, 8. Here we sequence the draft genome of an approximately 24,000-year-old individual (MA-1), from Mal’ta in south-central Siberia9, to an average depth of 1×. To our knowledge this is the oldest anatomically modern human genome reported to date. The MA-1 mitochondrial genome belongs to haplogroup U, which has also been found at high frequency among Upper Palaeolithic and Mesolithic European hunter-gatherers10, 11, 12, and the Y chromosome of MA-1 is basal to modern-day western Eurasians and near the root of most Native American lineages5. Similarly, we find autosomal evidence that MA-1 is basal to modern-day western Eurasians and genetically closely related to modern-day Native Americans, with no close affinity to east Asians. This suggests that populations related to contemporary western Eurasians had a more north-easterly distribution 24,000 years ago than commonly thought. Furthermore, we estimate that 14 to 38% of Native American ancestry may originate through gene flow from this ancient population. This is likely to have occurred after the divergence of Native American ancestors from east Asian ancestors, but before the diversification of Native American populations in the New World. Gene flow from the MA-1 lineage into Native American ancestors could explain why several crania from the First Americans have been reported as bearing morphological characteristics that do not resemble those of east Asians2, 13. Sequencing of another south-central Siberian, Afontova Gora-2 dating to approximately 17,000 years ago14, revealed similar autosomal genetic signatures as MA-1, suggesting that the region was continuously occupied by humans throughout the Last Glacial Maximum. Our findings reveal that western Eurasian genetic signatures in modern-day Native Americans derive not only from post-Columbian admixture, as commonly thought, but also from a mixed ancestry of the First Americans.


    Haploid lineages

    The Mal'ta boy, MA-1, carried distinct yDNA R* and mtDNA U* lineages. While both are clearly related to those dominant in Europe and parts of Asia (West, South) nowadays, they are also distinct from any specific dominant lineage today.

    R* (yDNA) is neither R1 nor R2 but another distinct branch of R. This kind of R(xR1, R2) is most rare today and found mostly in and around NW South Asia. Following Wikipedia, this "other R" is found in:
    • 10.3% among the Burusho
    • 6.8% among the Kalash
    • 3.4% among the Gujarati
    However I must say that I recall from old discussions that some R(xR1) is also found among Mongols and some North American Natives. I would have to find the relevant studies though (maybe in an update).

    U* (mtDNA) is also quite rare today but has been found in Swabian Magdalenian hunter-gatherers, as well as in some Neolithic samples, although it may well be a totally different kind of U* (I could not discern the specific markers in the paper nor the supplementary materials and it must be reminded that the asterisk only means "others").


    Autosomal DNA

    The study also shows some statistical inferences from the autosomal (or nuclear) DNA of the Mal'ta boy:


    Figure 1 [b & c]
    b, PCA (PC1 versus PC2) of MA-1 and worldwide human populations for which genomic tracts from recent European admixture in American and Siberian populations have been excluded19.
    c, Heat map of the statistic f3(Yoruba; MA-1, X) where X is one of 147 worldwide non-African populations (standard errors shown in Supplementary Fig. 21). The graded heat key represents the magnitude of the computed f3 statistics.


    Here we can appreciate that MA-1 is closest to Native Americans but still rather intermediate between them and South and West Eurasians. Interestingly East Asians are quite distant instead, suggesting that MA-1 was still not too much admixed with that continental population, unlike what happens with Native Americans, who are essentially East Asian in the autosomal and mtDNA aspects. So this kid appears to be some sort of a "missing link" in the Paleolithic ethnogenesis of Native Americans.



    Figure 2 | Admixture graph for MA-1 and 16 complete genomes. An admixture graph with two migration edges (depicted by arrows) was fitted using TreeMix21 to relate MA-1 to 11 modern genomes from worldwide populations22, 4 modern genomes produced in this study (Avar, Mari, Indian and Tajik), and the Denisova genome22. Trees without migration, graphs with different number of migration edges, and residual matrices are shown in Supplementary Information, section 11. The drift parameter is proportional to 2Ne generations, whereNe is the effective population size. The migration weight represents the fraction of ancestry derived from the migration edge. The scale bar shows ten times the average standard error (s.e.) of the entries in the sample covariance matrix. Note that the length of the branch leading toMA-1 is affected by this ancient genome being represented by haploid genotypes.

    Even if I am not too keen of TreeMix, in this case the results seem consistent.

    We can appreciate here that a sample of Native Americans (the Karitiana, maybe not as "pure" as the Xavantes but still very much so) show up in a different branch from MA-1, reflecting their overwhelmingly East Asian ancestry, mostly by the maternal side (mtDNA). MA-1 instead hangs from the South-West Eurasian branch, soon after the split between South Asians and West Eurasians. Both have extremely drifted branches, surely indicating the small size of their founder populations, typical of the Far North. 

    In addition to this basic tree, two admixture events are signaled: one is the already known Denisovan (H. erectus?) weak one into Australasian Natives (represented by Papuans) and the other one, quite more intense, is the one hanging from upstream of MA-1 to Native Americans (Karitiana), reflecting the partial South-West Eurasian ancestry of Native Americans (noticeable also in their dominant paternal ancestry: haplogroup Q). 

    The fact that the admixture signal stems from quite upstream of MA-1 indicates that this boy (or rather his relatives) were not direct ancestors of Native Americans in any significant way but rather a different branch from the same trunk. Probably proto-Amerindians were already in this period at the North Pacific coasts, not sure if in Beringia or around Okhotsk or what but certainly they had already separated from the Mal'ta population.


    What did we know of Native American genesis before this finding?

    There are three principal lines of evidence:
    1. Y-DNA, which among Native Americans is essentially haplogroup Q (plus some C3, which is from NE Asia). By phylogenetically hierarchical diversity, haplogroup Q must have coalesced in West or Central Asia (or maybe South Asia?), very possibly in or near Iran. The NE Asian and Native American branches are clearly derived, even if more important numerically today.
    2. mtDNA, which among Native Americans is essentially from NE Asia (A, C, D), middle East Asia (B) but also in a small amount from West Asia (X2). 
    3. Archaeology: we can track, more or less directly, the proto-NAs by means of following the Upper Paleolithic sequence in Siberia and nearby areas. 
      1. C. 47,000 years ago (calBP) H. sapiens with Aurignacoid technology (i.e. linked to West Eurasian earliest Upper Paleolithic) reached Altai, displacing the Neanderthals to the Northern fringes of the district.
      2. C. 30,000 years ago, Upper Paleolithic ("mode 4") technology with roots in Altai reached other parts of Siberia, Mongolia and North China, from where it expanded eastwards and southwards gradually in a process of, probably, cultural diffusion. 
      3. By c. 17,000 years ago they were already in North America and c. 15,000 years ago in South America. In the LGM they were probably in Beringia already (but this is only indirectly attested so far). 
    So we already had a good idea about the origins of Native Americans: their ultimate roots, at least patrilineally, seem to be in Altai (where they were part of the wider West Eurasian colonization at the expense of Neanderthals with Aurignacian-like technology and dogs). Then, probably around 30,000 years ago they expanded eastwards through Siberia and maybe nearby areas, entering in intense and intimate contact with the already existent East Asian populations, with whom they admixed once and again, mostly by the female side. 

    It would seem therefore that their society was already patrilocal because otherwise their patrilineages would have just got dissolved among the locals and would have never reached Beringia nor America in such dominant position.

    Overall this is the quite clear notion that I have on Native American earliest genesis and for me there is no reasonable doubt about this narrative (except maybe in the fine details). However I must reckon that some individuals have reacted very negatively against it. But no matter how much they yell, I fail to see their arguments. 


    How does this new finding affects this narrative?

    It simply confirms it with further evidence. By 24,000 calBP the proto-NAs were surely already, as I said before, in NE Asia close to the Pacific coasts, so this Mal'ta population is a branch left behind in their migration (plus whatever new inflows from the West, which we can't evaluate). The very low affinity level with East Asians, in spite of its quite Eastern location, shows that early East Asians had not yet reached, at least in significant numbers, so far North. If they had, they probably did only at more eastern longitudes, probably near the sea, where resources were more plentiful.

    In other words: the first Central Siberians were of South+West Eurasian stock and the current East Asian genetic and phenotype hegemony in that area reflects post-LGM flows, mostly lead by yDNA N1. 

    Early Native Americans were the product of admixture of these earliest Siberians with NE Asians, admixture that surely happened East of Lake Baikal, although the exact details are still unclear. 


    What does MA-1 say about the West?

    His mtDNA is generally consistent with other common U-derived lineages found in West Eurasian Upper Paleolithic, so not much other than he was somehow related, what is confirmed by autosomal analysis. 

    His yDNA is more interesting maybe, nonetheless because it is probably the oldest sequence of this kind but also because it belongs to haplogroup R. It certainly discards whatever "molecular clock" guesstimates for R that are shorter than this site's age but on its own it is not able to set a real age other than a bare minimum. 

    So for example Eupedia's estimate of 29 Ka for R as such could still be valid, although I would say that extremely unlikely. 

    Indirectly however it does say something by confirming the overall narrative of Native American origins as above and that means that Eupedia's estimate of a mere 24 Ka age for haplogroup Q is almost certainly wrong by a lot. 

    Using that tree, we would have to at least double the age of Q in order to fit with the Altai narrative (which begins at c. 47 Ka ago), what, extrapolating, implies an age for R of at least 58 Ka. I have estimated some 48 Ka of age for R1 and 68 Ka for P, so it makes good sense after these so necessary corrections. The exact ages we may never know but the approximate ages should be something like these. 


    And that's about all I can say. More in comments (and/or updates) if need be.



    Update (Dec 6): R* and P* (and other rare clades) among Central Asians

    A reader sent me copy of the study by Wei-Hua Shou et al. (2010) titled Y-chromosome distributions among populations in Northwest China identify significant contribution from Central Asian pastoralists and lesser influence of western Eurasians, published by Nature (doi:10.1038/jhg.2010.30).

    While it is not the bit of info I was recalling above, it does add some information about unmistakable R(xR1,R2) and P(xQ,R) among Central Asian populations (from P.R. China territory). In detail:
    • R* is found in 5/31 Tayiks, 1/41 Kazakhs and 1/50 Uyghurs.
    • P* is found in 1/31 Tayiks and 1/43 Kirgizes. 
    Also of interest should be the presence of:
    • Q(xQ1) in  8/35 Dongxiang (a Mongol ethnicity), 1/45 Kirgizes and 1/50 Tu (another Mongol ethnicity).
    • F(xG,H,I,J,K) in 2/32 Yugu (Yugurs, a distinct Uyghur sub-ethnicity), 2/41 Kazakh, 1/31 Tayiks and 1/50 Tu.
    • K(xN,O,P) in  32/533 total (i.e. 6% in Easternmost Central Asia), among which are most notable: 9/50 Uyghurs, 6/23 Uzbeks, 6/27 Bao'an (another small Mongol ethnicity), 3/32 Xibo (a Tungusic ethnicity), 2/32 Yugu and 2/5 Mongols. I guess that it is possible that this is a distinct K subclade, although it can well be either part of MNOPS (NO*?) or also belong to LT (L?).
    • R2 in 1/31 Tayiks and 2/27 Bao'an.

    September 9, 2013

    Homo sapiens was in China before 100,000 years ago!

    This finding consolidates the recent dating of African-like industries of India to c. 96,000 years ago, as well as other previous discoveries from mostly China, and, jointly, they totally out-date not just the ridiculous "60 Ka ago" mantra for the migration out-of-Africa (which we know is dated to c. 125,000 years ago in Arabia and Palestine) but also the previous estimates of c. 80,000 years ago for India (Petraglia 2007).

    Guanjung Shen et al., Mass spectrometric U-series dating of Huanglong Cave in Hubei Province, central China: Evidence for early presence of modern humans in eastern Asia. Journal of Human Evolution, 2013. Freely accessible at the time of writing thisLINK [doi:10.1016/j.jhevol.2013.05.002]

    Abstract

    Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ∼50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia.

    The range of dates for the teeth is ample but the oldest one is of 102.1 ± 0.9 Ka ago. Other dates are very close to this one: 99.5 ± 2.2, 99.3 ± 1.6, 96.8 ± 1.0, etc. (see table 1), so there can be little doubt about their accuracy. 

    The Huanglong teeth (various views)
     
    Now, how solidly can these teeth be considered to belong to the species Homo sapiens? Very solidly it seems:
    The seven hominin teeth from Huanglong Cave have been assigned to AMH mainly because of their generally more advanced morphology than that of H. erectus and other archaic populations (Liu et al., 2010b), especially in terms of the crown breath/length index. These teeth also lack major archaic suprastructural characteristics listed by Bermúdez de Castro (1988) for eastern Asian mid-Pleistocene hominins, such as “strong tuberculum linguale (incisors), marked lingual inclination of the buccal face (incisors and canines), buccal cingulum (canines and molars), wrinkling (molars), taurodontism (molars), swelling of the buccal faces (molars)” (Tim Compton, Personal communication). However, in their roots, these teeth still retain a few archaic features, being more robust and complicated than those of modern humans (Liu et al., 2010b).

    Zhirendong jaw
    Let's not forget that further South in China, in Zhirendong, a "modern" jaw was found and dated to c. 100,000 years ago as well.

    As for the so-called "molecular clock":
    The new timeline for human evolution in China is in disagreement with the molecular clock that posits a late appearance for AMH in eastern Asia (e.g., Chu et al., 1998).

    ... too bad for the "clock", because a clock that doesn't inform us of time with at least some accuracy is totally useless.