May 19, 2016

35,000 year old mtDNA haplogroup U6 from Romania

I wouldn't be very surprised if many of the markers supposedly signifying recent gene flow Africa and Eurasia were actually quite old in Eurasia. The trouble is that reports of such gene flow were often based on simply observing that marker "X" occurs at a higher frequency in Africa than in Eurasia, so a common sense explanation is that it reflects limited recent gene flow between the continents. But, it is now known that common sense is not always the best guide, as e.g., ancient Europeans had mtDNA haplogroup M (in the past considered evidence of Asian admixture), Y-chromosome haplogroup C (ditto), and now U6.

The same should also apply to the Middle East where there has been admixture with Africans since the Islamic period at least. The existence of such admixture does not mean that every single lineage that occurs at low frequency in the Middle East and high frequency in Africa is diagnostic of this later period of admixture. Some of them could well be relics of old Middle Eastern populations. Who knows what people inhabited the presently inhospitable landscape of the Saharan-Arabian desert zone? The living populations can certainly make no claim to being the first ones there, but the genetic heritage of those earlier occupants may still persist in them in traces.

Similarly for the New World; in that case, there is a better case that European-looking lineages are indeed due to the colonization of the Americas over the last five centuries. However, that does not mean that all of them are, and we should be mindful of the possibility of pre-Columbian contact between the Old and New worlds.

Scientific Reports 6, Article number: 25501 (2016)

The mitogenome of a 35,000-year-old Homo sapiens from Europe supports a Palaeolithic back-migration to Africa

M. Hervella et al.

After the dispersal of modern humans (Homo sapiens) Out of Africa, hominins with a similar morphology to that of present-day humans initiated the gradual demographic expansion into Eurasia. The mitogenome (33-fold coverage) of the Peştera Muierii 1 individual (PM1) from Romania (35 ky cal BP) we present in this article corresponds fully to Homo sapiens, whilst exhibiting a mosaic of morphological features related to both modern humans and Neandertals. We have identified the PM1 mitogenome as a basal haplogroup U6*, not previously found in any ancient or present-day humans. The derived U6 haplotypes are predominantly found in present-day North-Western African populations. Concomitantly, those found in Europe have been attributed to recent gene-flow from North Africa. The presence of the basal haplogroup U6* in South East Europe (Romania) at 35 ky BP confirms a Eurasian origin of the U6 mitochondrial lineage. Consequently, we propose that the PM1 lineage is an offshoot to South East Europe that can be traced to the Early Upper Paleolithic back migration from Western Asia to North Africa, during which the U6 lineage diversified, until the emergence of the present-day U6 African lineages.

Link

May 11, 2016

74 loci associated with educational attainment

Other than the claim in the abstract that educational attainment is "mostly environmentally determined" (*), this seems like a very useful study, as it identifies 74 loci associated with educational attainment and explores their interesting biology. 

The utility of this type of study does not consist so much in the ability to predict one's educational potential by looking at one's genotype (we're a long way off from that, and a traditional pencil-and-paper test will probably beat genetics for a long time to come). Rather, it helps move the culture forward, away from the polite ultra-egalitarianism of today's dominant worldview and towards a more scientific attitude concerning the limits of education. Such an attitude will necessarily acknowledge -whether it seems fair to us or not- that genes sometimes dictate that the smart but slothful kid should outperform his diligent but dull-witted peer.

It will certainly be very interesting to see what better methods or even larger sample sizes will bring in years to come.

(*) The heritability of educational attainment has been estimated to be 67-74% of Norwegian males of the 1940-1961 period. There is actually no "universal heritability" of a trait. In a third world country it may very well be that one's educational attainment is determined mostly by environmental effects such as whether you have access to a school within reasonable distance or to just enough food during development. In a modern country (like post-war Norway or a technologically advanced future utopia), environmental effects are expected to be minimal (as everyone will get the best of everything), and variation in educational attainment will simply be due to genes (+noise).

Nature (2016) doi:10.1038/nature17671

Genome-wide association study identifies 74 loci associated with educational attainment 

Aysu Okbay et al.

Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals1. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our earlier discovery sample1, 2 of 101,069 individuals to 293,723 individuals, and a replication study in an independent sample of 111,349 individuals from the UK Biobank. We identify 74 genome-wide significant loci associated with the number of years of schooling completed. Single-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural development. Our findings demonstrate that, even for a behavioural phenotype that is mostly environmentally determined, a well-powered GWAS identifies replicable associated genetic variants that suggest biologically relevant pathways. Because educational attainment is measured in large numbers of individuals, it will continue to be useful as a proxy phenotype in efforts to characterize the genetic influences of related phenotypes, including cognition and neuropsychiatric diseases.

Link

May 08, 2016

Natural selection in Britain during the last 2,000 years

The latest ancient DNA studies from the British Isles (Schiffels et al and Martiniano et al. and Cassidy et al.) support continuity over the last 2,000 years. Sure, there were continued migrations like the arrival of the Anglo-Saxons, but these were very similar groups in the grand scheme of things.

But, while ancestrally the modern Briton is probably a descendant of the Britons of 2,000 years ago with some admixture from similar continental European groups, he is not the same, as (apparently) substantial genetic adaptation has continued to operate in Britain over the same period. A new preprint by Field, Boyle, Telis et al. makes the case for adaptation in a variety of traits in the ancestors of Britons over this period. Mind you, the genetic underpinnings of many important human traits known to have high heritability are currently unknown, but there is little doubt that selection would have affected traits beyond those detected in this study. I am quite curious to see whether the striking efflorescence of cultural achievement in Britain over the last half millennium could have (at least in part) a genetic underpinning.

Depigmentation is a trait whose genetic architecture is as well as understood as any. The results of this study might surprise writers of decades and centuries past who supposed that the spectrum of pigmentation of modern Europeans was the result  of admixture-in varying measure- between Xanthochrooi and Melanchrooi races of primordial antiquity. All indications seem to be that depigmentation of hair, skin, and eyes did not co-occur in such a hypothetical race, but rather in different parts of the Caucasoid range, only reaching a high combined frequency in northern Europe to form the distinctive physical type that is distinctive of the natives of that region. It would be quite interesting to see how these traits evolved in Fennoscandia and the Baltic, regions that sport an even higher depigmentation than the British Isles. Traditionally, these areas were viewed as refuges of the Xanthochrooi but it may very well turn out to be that for whatever reason selection has acted in that area as well, as it did in the Eastern European plain where rather dark Bronze Age steppe groups gave way to rather light pigmented living eastern Slavs.

bioRxiv doi: http://dx.doi.org/10.1101/052084

Detection of human adaptation during the past 2,000 years

Yair Field, Evan A Boyle, Natalie Telis, Ziyue Gao, Kyle J Gaulton, David Golan, Loic Yengo, Ghislain Rocheleau, Philippe Froguel, Mark I McCarthy, Jonathan K Pritchard

Detection of recent natural selection is a challenging problem in population genetics, as standard methods generally integrate over long timescales. Here we introduce the Singleton Density Score (SDS), a powerful measure to infer very recent changes in allele frequencies from contemporary genome sequences. When applied to data from the UK10K Project, SDS reflects allele frequency changes in the ancestors of modern Britons during the past 2,000 years. We see strong signals of selection at lactase and HLA, and in favor of blond hair and blue eyes. Turning to signals of polygenic adaptation we find, remarkably, that recent selection for increased height has driven allele frequency shifts across most of the genome. Moreover, we report suggestive new evidence for polygenic shifts affecting many other complex traits. Our results suggest that polygenic adaptation has played a pervasive role in shaping genotypic and phenotypic variation in modern humans.

Link

May 02, 2016

Neandertal ancestry, going, going, ..., gone (?)

A deluge of new data from Upper Paleolithic Europe will give us all a lot to think about. It is incredible that Neandertal ancestry seems to have decreased over time in Europe (Oase1 is off-cline with lots of extra Neandertal ancestry from a recent genealogical Neandertal in the family tree). The functional form of the decrease seems pretty well approximated as linear.

The authors write:
Using one statistic, we estimate a decline from 4.3–5.7% from a time shortly after introgression to 1.1–2.2% in Eurasians today (Fig. 2).
This is remarkable because it shows  that most of the Neandertal ancestry of the earliest AMH in Europe was gone by the Mesolithic. It really seems that Neandertal genes were bred out of the gene pool over time. Will this trend continue into the future? Perhaps only minute traces of Neandertal DNA will remain in humans in 10,000 more years. Some of Neandertal DNA may yet prove to be neutral or beneficial, so at the limit the percentage may be more than zero. Nonetheless, the historical trend does suggest that modern humans inherited mostly genetic garbage from Neandertals and evolution is more than halfway through the process of getting rid of it.

As a corollary, there may have been other episodes of archaic admixture that are no longer detectable. Perhaps our modern human lineage has repeatedly admixed with other species, but traces of those admixtures are long gone by the action of natural selection. The reason for our relative homogeneity as a species may not be that we avoided intermixing with others, but that, sadly, most others had not much that was beneficial to offer to our ancestors.

Nature (2016) doi:10.1038/nature17993

The genetic history of Ice Age Europe

Qiaomei Fu et al.

Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. Here we analyse genome-wide data from 51 Eurasians from ~45,000–7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas there is no evidence of the earliest modern humans in Europe contributing to the genetic composition of present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans. An ~35,000-year-old individual from northwest Europe represents an early branch of this founder population which was then displaced across a broad region, before reappearing in southwest Europe at the height of the last Ice Age ~19,000 years ago. During the major warming period after ~14,000 years ago, a genetic component related to present-day Near Easterners became widespread in Europe. These results document how population turnover and migration have been recurring themes of European prehistory.

Link

April 30, 2016

More on Kennewick Man

A new technical report re-analyzes the data of Rasmussen et al. study on Kennewick man and confirms that he is related to Native Americans. From the report:
We find the Kennewick sample has the highest shared similarity to Native American populations with the highest values observed being with populations from South America (Figure 7), in line with the observations from Rasmussen et al.
Hopefully this will end the campaign to put him back to the ground. I have added a horizontal line to the new study's Figure 7 to mark the population claiming the skeleton among the huge number considered, showing that there's no particularly strong relationship to it (the strongest connection is at the bottom of the figure).


The Rasmussen et al. and Novembre et al. studies are really science working at its best: simultaneously falsifying claims that Kennewick was some sort of Australoid (or even more implausibly Caucasoid) based on its craniofacial morphology, but not overreaching to validate emotional appeals to make him into an ancestor he wasn't. Thankfully, the way forward is to keep studying Kennewick Man (and modern Native Americans) with ever-better data and techniques which may turn up (who knows?) a real (rather than imagined) ancestral link.


Technical Report: Assessment of the genetic analyses of Rasmussen et al. (2015)

John Novembre, PhD, David Witonsky, Anna Di Rienzo, PhD

The primary aim of the analysis undertaken here (U.S. Army Corps of Engineers, St Louis District Contract #W912P9-16-P-0010) is to provide an independent validation of the genetic evidence underlying a recent publication by Morten Rasmussen and colleagues on July 23rd, 2015, in Nature (Vol 523:455–58). Based on our analysis of the Kennewick Man’s sequence data and Colville tribe genotype data generated by Rasmussen et al., we concur with the findings of the original paper that the sample is genetically closer to modern Native Americans than to any other population worldwide. We carried out several analyses to support this conclusion, including (i) principal component analysis (PCA; Patterson et al. 2006), (ii) unsupervised genetic clustering using ADMIXTURE (Alexander, Novembre, and Lange 2009), (iii) estimation of genetic affinity to modern human populations using f3 and D statistics (Patterson et al. 2012), and (iv) a novel approach based on the geographic distribution of rare variants. Importantly, these distinct analyses, spanning three non-overlapping subsets of the data, are each consistent with Native American ancestry.

Link

April 25, 2016

Bursts in human male demography

From the paper:
When the tree is calibrated with a mutation rate estimate of 0.76 × 10-9 mutations per base pair per year9, the time to the most recent common ancestor (TMRCA) of the tree is ~190,000 years, but we consider the implications of alternative mutation rate estimates below. Of the clades resulting from the four deepest branching events, all but one are exclusive to Africa, and the TMRCA of all non-African lineages (that is, the TMRCA of haplogroups DE and CF) is ~76,000 years (Fig. 1, Supplementary Figs. 18 and 19, Supplementary Table 10, and Supplementary Note). We saw a notable increase in the number of lineages outside Africa ~50–55 kya, perhaps reflecting the geographical expansion and differentiation of Eurasian populations as they settled the vast expanse of these continents. Consistent with previous proposals14, a parsimonious interpretation of the phylogeny is that the predominant African haplogroup, haplogroup E, arose outside the continent. This model of geographical segregation within the CT clade requires just one continental haplogroup exchange (E to Africa), rather than three (D, C, and F out of Africa). Furthermore, the timing of this putative return to Africa—between the emergence of haplogroup E and its differentiation within Africa by 58 kya—is consistent with proposals, based on non–Y chromosome data, of abundant gene flow between Africa and nearby regions of Asia 50–80 kya15.
I've long argued for the Y-chromosome haplogroup E migration into Africa and it is nice to see this common-sense interpretation finally adopted. Too much focus has been placed on figuring out which routes modern humans took out of Africa, and not at all to figure out how Eurasian males came to overwhelm the African Y-chromosome gene pool so decisively. The Eurasian migration into Africa must have taken place in the ~70-60kya window, constrained by the D/E split and  the deepest intra-African E splits. I think that the Out-of-Arabia scenario I outlined in 2012 continues to make a lot of sense. It would be awesome to get data from the first Later Stone Age people from Africa which are probably the best bet to trace this migration from Eurasia into Sub-Saharan Africa.

Nature Genetics (2016) doi:10.1038/ng.3559

Punctuated bursts in human male demography inferred from 1,244 worldwide Y-chromosome sequences

G David Poznik et al.

We report the sequences of 1,244 human Y chromosomes randomly ascertained from 26 worldwide populations by the 1000 Genomes Project. We discovered more than 65,000 variants, including single-nucleotide variants, multiple-nucleotide variants, insertions and deletions, short tandem repeats, and copy number variants. Of these, copy number variants contribute the greatest predicted functional impact. We constructed a calibrated phylogenetic tree on the basis of binary single-nucleotide variants and projected the more complex variants onto it, estimating the number of mutations for each class. Our phylogeny shows bursts of extreme expansion in male numbers that have occurred independently among each of the five continental superpopulations examined, at times of known migrations and technological innovations.

Link

April 24, 2016

Jewish and Indian ancestry in the Bene Israel

PLoS ONE 11(3): e0152056. doi:10.1371/journal.pone.0152056

The Genetics of Bene Israel from India Reveals Both Substantial Jewish and Indian Ancestry
Yedael Y. Waldman , Arjun Biddanda , Natalie R. Davidson, Paul Billing-Ross, Maya Dubrovsky, Christopher L. Campbell, Carole Oddoux, Eitan Friedman, Gil Atzmon, Eran Halperin, Harry Ostrer, Alon Keinan

The Bene Israel Jewish community from West India is a unique population whose history before the 18th century remains largely unknown. Bene Israel members consider themselves as descendants of Jews, yet the identity of Jewish ancestors and their arrival time to India are unknown, with speculations on arrival time varying between the 8th century BCE and the 6th century CE. Here, we characterize the genetic history of Bene Israel by collecting and genotyping 18 Bene Israel individuals. Combining with 486 individuals from 41 other Jewish, Indian and Pakistani populations, and additional individuals from worldwide populations, we conducted comprehensive genome-wide analyses based on FST, principal component analysis, ADMIXTURE, identity-by-descent sharing, admixture linkage disequilibrium decay, haplotype sharing and allele sharing autocorrelation decay, as well as contrasted patterns between the X chromosome and the autosomes. The genetics of Bene Israel individuals resemble local Indian populations, while at the same time constituting a clearly separated and unique population in India. They are unique among Indian and Pakistani populations we analyzed in sharing considerable genetic ancestry with other Jewish populations. Putting together the results from all analyses point to Bene Israel being an admixed population with both Jewish and Indian ancestry, with the genetic contribution of each of these ancestral populations being substantial. The admixture took place in the last millennium, about 19–33 generations ago. It involved Middle-Eastern Jews and was sex-biased, with more male Jewish and local female contribution. It was followed by a population bottleneck and high endogamy, which can lead to increased prevalence of recessive diseases in this population. This study provides an example of how genetic analysis advances our knowledge of human history in cases where other disciplines lack the relevant data to do so.

Link

April 14, 2016

Periods of human activity in Chauvet-Pont d'Arc cave

PNAS DOI: doi: 10.1073/pnas.1523158113

A high-precision chronological model for the decorated Upper Paleolithic cave of Chauvet-Pont d’Arc, Ardèche, France

Anita Quiles et al.

Radiocarbon dates for the ancient drawings in the Chauvet-Pont d’Arc Cave revealed ages much older than expected. These early ages and nature of this Paleolithic art make this United Nations Educational, Scientific and Cultural Organization (UNESCO) site indisputably unique. A large, multidisciplinary dating program has recently mapped the anthropological evolution associated with the cave. More than 350 dates (by 14C, U-Th, TL and 36Cl) were obtained over the last 15 y. They include 259 radiocarbon dates, mainly related to the rock art and human activity in the cave. We present here more than 80 previously unpublished dates. All of the dates were integrated into a high-precision Bayesian model based on archaeological evidence to securely reconstruct the complete history of the Chauvet-Pont d’Arc Cave on an absolute timescale. It shows that there were two distinct periods of human activity in the cave, one from 37 to 33,500 y ago, and the other from 31 to 28,000 y ago. Cave bears also took refuge in the cave until 33,000 y ago.

Link

April 10, 2016

Nubian assemblages from the Negev

Nubian assemblages from the Levant are quite important because they provide an intermediate link (along land routes) between those from Africa and Arabia. It's also more difficult now to consider the Arabian finds as a limited event without broader implications about modern human dispersals. From the paper:
Mapping the earliest dated sites that contain a Nubian component does not permit an unequivocal identification of a region of origin for the Nubian Technology.
Quaternary International doi:10.1016/j.quaint.2016.02.008

“Diffusion with modifications”: Nubian assemblages in the central Negev highlands of Israel and their implications for Middle Paleolithic inter-regional interactions

Mae Goder-Goldberger, Natalia Gubenko, Erella Hovers

Nubian Levallois cores, now known from sites in eastern Africa, the Nile Valley and Arabia, have been used as a material culture marker for Upper Pleistocene dispersals of hominins out of Africa. The Levantine corridor, being the only land route connecting Africa to Eurasia, has been viewed as a possible dispersal route. We report here on lithic assemblages from the Negev highlands of Israel that contain both Levallois centripetal and Nubian-type cores. Wetter conditions over the Sahara and Negev deserts during MIS 6a–5e provided a generally continuous environmental corridor into the Levant that enabled the dispersal of hominin groups bearing the Nubian variant of prepared core technologies. The Negev assemblages draw renewed attention to the place of the Levant as one of the dispersal routes out of Africa during the Late Pleistocene and could suggest that processes of human dispersals and cultural diffusion resulted in the spread of Nubian technology across eastern Africa, the western Sahara and the Nile Valley, the southern Levant and Arabia.

Link

April 07, 2016

Neandertal Y-chromosome (finally)

It's been six years since the publication of the draft Neandertal genome, and one piece of the puzzle that's always been missing is the Neandertal Y-chromosome (unfortunately most of the Neandertals yielding data were female). But, the wait is finally over, with the first publication of Neandertal Y-chromosome data.

AJHG Volume 98, Issue 4, p728–734, 7 April 2016

The Divergence of Neandertal and Modern Human Y Chromosomes

Fernando L. Mendez, G. David Poznik, Sergi Castellano, Carlos D. Bustamante

Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes—including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447–806 kya). This is ∼2.1 (95% CI: 1.7–2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups.

Link

April 01, 2016

Zhiren cave human remains: 116-106 ka old

Quaternary International doi:10.1016/j.quaint.2015.12.088

The age of human remains and associated fauna from Zhiren Cave in Guangxi, southern China

Yanjun Cai et al.

Zhiren Cave in southern China is an important site for the study of the origin and the environmental background of early modern humans. The combination of Elephas kiangnanensis, Elephas maximus, and Megatapirus augustus, indicates an early representative of the typical Asian elephant fauna. Previous U-series dating of flowstone calcite has pinpointed an upper age limit for the fossils of about 100 ka. In order to achieve a better comprehension of the chronology of the modern human and contemporaneous faunal assemblage, paleomagnetic, stratigraphic, and optically stimulated luminescence (OSL) dating methods have been applied to the cave sediments. Paleomagnetic analyses reveal that there is a reversed polarity excursion below the fossiliferous layer. This excursion can be regarded as the Blake excursion event, given the U-series ages of the overlying flowstone calcite, the OSL measurements, the virtual geomagnetic pole (VGP) path of the excursion, the two reverse polarity zones within this excursion event, and the characteristic of the fauna assemblage. The human remains and mammalian fauna assemblage can be bracketed to 116–106 ka. Application of OSL dating leads to erroneous ages, largely due to the uncertainty associated with the estimation on the dose rates.

Link

March 31, 2016

Denisovan ancestry in Oceanians (and some in South Asians)

Current Biology DOI: http://dx.doi.org/10.1016/j.cub.2016.03.037

The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans

Sriram Sankararaman et al.

Some present-day humans derive up to ∼5% [ 1 ] of their ancestry from archaic Denisovans, an even larger proportion than the ∼2% from Neanderthals [ 2 ]. We developed methods that can disambiguate the locations of segments of Denisovan and Neanderthal ancestry in present-day humans and applied them to 257 high-coverage genomes from 120 diverse populations, among which were 20 individual Oceanians with high Denisovan ancestry [ 3 ]. In Oceanians, the average size of Denisovan fragments is larger than Neanderthal fragments, implying a more recent average date of Denisovan admixture in the history of these populations (p = 0.00004). We document more Denisovan ancestry in South Asia than is expected based on existing models of history, reflecting a previously undocumented mixture related to archaic humans (p = 0.0013). Denisovan ancestry, just like Neanderthal ancestry, has been deleterious on a modern human genetic background, as reflected by its depletion near genes. Finally, the reduction of both archaic ancestries is especially pronounced on chromosome X and near genes more highly expressed in testes than other tissues (p = 1.2 × 10−7 to 3.2 × 10−7 for Denisovan and 2.2 × 10−3 to 2.9 × 10−3 for Neanderthal ancestry even after controlling for differences in level of selective constraint across gene classes). This suggests that reduced male fertility may be a general feature of mixtures of human populations diverged by >500,000 years.

Link

Middle (not Upper) Paleolithic hobbits

Nature (2016) doi:10.1038/nature17179

Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia

Thomas Sutikna, Matthew W. Tocheri, Michael J. Morwood, E. Wahyu Saptomo, Jatmiko, Rokus Due Awe, Sri Wasisto, Kira E. Westaway, Maxime Aubert, Bo Li, Jian-xin Zhao, Michael Storey, Brent V. Alloway, Mike W. Morley, Hanneke J. M. Meijer, Gerrit D. van den Bergh, Rainer Grün, Anthony Dosseto, Adam Brumm, William L. Jungers & Richard G. Roberts

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia)1, 2, 3, has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts2, 3, 4 and remains of other extinct endemic fauna5, 6, were dated to between about 95 and 12 thousand calendar years (kyr) ago2, 3, 7. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago8, 9, 10. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13–11 kyr cal. BP)1, 2, 3, 7, 11. Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago—potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans12, 13—is an open question.

Link

March 25, 2016

Bronze Age war in northern Germany

Slaughter at the bridge: Uncovering a colossal Bronze Age battle
About 3200 years ago, two armies clashed at a river crossing near the Baltic Sea. The confrontation can’t be found in any history books—the written word didn’t become common in these parts for another 2000 years—but this was no skirmish between local clans. Thousands of warriors came together in a brutal struggle, perhaps fought on a single day, using weapons crafted from wood, flint, and bronze, a metal that was then the height of military technology.

...

In 1996, an amateur archaeologist found a single upper arm bone sticking out of the steep riverbank—the first clue that the Tollense Valley, about 120 kilometers north of Berlin, concealed a gruesome secret. A flint arrowhead was firmly embedded in one end of the bone, prompting archaeologists to dig a small test excavation that yielded more bones, a bashed-in skull, and a 73-centimeter club resembling a baseball bat. The artifacts all were radiocarbon-dated to about 1250 B.C.E., suggesting they stemmed from a single episode during Europe’s Bronze Age.

...

Northern Europe in the Bronze Age was long dismissed as a backwater, overshadowed by more sophisticated civilizations in the Near East and Greece. Bronze itself, created in the Near East around 3200 B.C.E., took 1000 years to arrive here. But Tollense’s scale suggests more organization—and more violence—than once thought. “We had considered scenarios of raids, with small groups of young men killing and stealing food, but to imagine such a big battle with thousands of people is very surprising,” says Svend Hansen, head of the German Archaeological Institute’s (DAI’s) Eurasia Department in Berlin. The well-preserved bones and artifacts add detail to this picture of Bronze Age sophistication, pointing to the existence of a trained warrior class and suggesting that people from across Europe joined the bloody fray.

...

There was reason for skepticism. Before Tollense, direct evidence of large-scale violence in the Bronze Age was scanty, especially in this region. Historical accounts from the Near East and Greece described epic battles, but few artifacts remained to corroborate these boastful accounts. “Even in Egypt, despite hearing many tales of war, we never find such substantial archaeological evidence of its participants and victims,” UCD’s Molloy says.

...

Ancient DNA could potentially reveal much more: When compared to other Bronze Age samples from around Europe at this time, it could point to the homelands of the warriors as well as such traits as eye and hair color. Genetic analysis is just beginning, but so far it supports the notion of far-flung origins. DNA from teeth suggests some warriors are related to modern southern Europeans and others to people living in modern-day Poland and Scandinavia. “This is not a bunch of local idiots,” says University of Mainz geneticist Joachim Burger. “It’s a highly diverse population.”