john hawks weblog

paleoanthropology, genetics and evolution

Europe

  • Cro-Magnon 1, dating and mtDNA

    Fri, 2013-04-26 10:57 -- John Hawks

    I'm running through the new paper from Qiaomei Fu and colleagues [1] about Upper Paleolithic mtDNA genomes. Probably several readers were wondering, as I did, about this passage in the paper concerning Cro-Magnon 1:

    The exception was the Cro-Magnon 1 sample, which belonged to the derived hg T2b1, an unexpected hg given its putative age of 30,000 years [16]. Since the radiocarbon date for this specimen was obtained from an associated shell [16], we dated the sample itself using accelerator mass spectrometry (AMS). Surprisingly, the sample had a much younger age of about 700 years, suggesting a medieval origin. Consequently, this bone fragment has now been removed from the Cro-Magnon collection at the Musée de l’Homme in Paris. Attempts to directly date other remains from the Cro-Magnon type collection unfortunately failed. The good molecular preservation of our sample for both DNA and AMS dating, in contrast, suggests that this particular bone has a different origin from the other remains in the collection.

    Cro-Magnon 1 is one of the most recognizable Upper Paleolithic cranial specimens from Europe, and its date has often been questioned -- largely because the very early excavation of this site by Louis Lartet came early in the history of European prehistory, when many excavations proceeded without appreciating the stratigraphic complexities of sites.

    I have checked with Alain Froment and Johannes Krause on the status of this bone. The bone sample was taken from a tibia fragment that was not clearly associated with the rest of the collection. None of the Cro-Magnon human remains has yet yielded a radiocarbon date, and Alain indicates that the organic carbon is gone. So the current paper does not challenge the Cro-Magnon date, it merely subtracts an intrusive element.

    References

    1. Fu Q, Mittnik A, Johnson PLF, Bos K, Lari M, Bollongino R, Sun C, Giemsch L, Schmitz R, Burger J, et al. A revised timescale for human evolution based on ancient mitochondrial genomes. Curr Biol. 2013;23(7):553-9.
    Tags: 
    Cro-Magnon
    Upper Paleolithic
    France
    Europe
    mtDNA
    dating

  • Cheesy evidence

    Wed, 2012-12-12 14:40 -- John Hawks

    I'm totally socked in with work this week, but this new paper in Nature is an interesting piece of archaeological chemistry relevant to diet change in the European Neolithic: "Earliest evidence for cheese making in the sixth millennium bc in northern Europe" [1].

    The finding of abundant milk residues in pottery vessels from seventh millennium sites from north-western Anatolia provided the earliest evidence of milk processing, although the exact practice could not be explicitly defined1. Notably, the discovery of potsherds pierced with small holes appear at early Neolithic sites in temperate Europe in the sixth millennium BC and have been interpreted typologically as ‘cheese-strainers’10, although a direct association with milk processing has not yet been demonstrated. Organic residues preserved in pottery vessels have provided direct evidence for early milk use in the Neolithic period in the Near East and south-eastern Europe, north Africa, Denmark and the British Isles, based on the δ13C and Δ13C values of the major fatty acids in milk1, 2, 3, 4. Here we apply the same approach to investigate the function of sieves/strainer vessels, providing direct chemical evidence for their use in milk processing. The presence of abundant milk fat in these specialized vessels, comparable in form to modern cheese strainers11, provides compelling evidence for the vessels having being used to separate fat-rich milk curds from the lactose-containing whey. This new evidence emphasizes the importance of pottery vessels in processing dairy products, particularly in the manufacture of reduced-lactose milk products among lactose-intolerant prehistoric farming communities.

    Nice job of narrowing down the function of pots from fragments, following the processing steps that are evidenced in known cases of milk and cheese production. The early presence of cheese making may also be relevant to the selection pressure for lactase persistence -- one argument being that cheese and yogurt production make lactase persistence less advantageous relative to non-persistence. If cheese making was there from nearly the start of the Neolithic, that implies that the fitness advantage of lactase persistence was strong even in its presence.

    References

    1. Salque M, Bogucki PI, Pyzel J, Sobkowiak-Tabaka I, Grygiel R, Szmyt M, Evershed RP. Earliest evidence for cheese making in the sixth millennium bc in northern Europe. Nature. 2012.
    Tags: 
    lactase
    diet
    Europe
    Neolithic

  • Recent evolution of coding variants

    Wed, 2012-12-05 01:00 -- John Hawks

    How did I get myself quoted in a story as the skeptic about recent human evolution? ("Human Evolution Enters an Exciting New Phase"). After all, I've been a huge advocate of the idea that recent human evolution was a lot faster and more interesting than anthropologists used to think ("Why human evolution accelerated").

    The story, by Brandom Keim, is a good account of a new paper in Nature by Wenqing Fu and colleagues, "Analysis of 6,515 exomes reveals the recent origin of most human protein-coding variants" [1]. It's a pretty cool study, which has identified protein-coding alleles in large samples of European-American and African-American individuals.

    Fu and colleagues compared all the coding variants they found in large samples of European-Americans and African-Americans, and discovered that the European-ancestry people have a higher fraction of rare coding variants. They propose that the rate of new coding variants entering and persisting within the population actually accelerated in the ancestral European population. Why would this happen? In their view, demography is the most likely explanation. As European populations expanded during the Neolithic and later time periods, the rate by which new mutations are lost by genetic drift began to decline. These new mutations have pooled up within the European population, giving them a glut of new changes to protein-coding sequences. Many of these mutations may be deleterious, just not bad enough for natural selection to have weeded them out in the growing ancient population.

    I think in large part this explanation is correct. In some ways it is incomplete.

    The effect of population history on our evolution was the theme of our 2007 paper on positive selection in recent humans [2]. We relied on exactly the same mathematical relations used in this new paper: More people means more different mutations entering the population. In our case, the increase in the total number of mutations meant that we could expect more potential adaptive mutations to be selected within a growing population. In this case, the increase in the total number of mutations means more mutations remain to be picked up by resequencing rare neutral or deleterious variations in present samples.

    One of the senior authors of the study, Joshua Akey, commented:

    Most of the mutations that we found arose in the last 200 generations or so. There hasn’t been much time for random change or deterministic change through natural selection. We have a repository of all this new variation for humanity to use as a substrate. In a way, we’re more evolvable now than at any time in our history.

    (this is quoted by Punnett Square, not sure about the original source)

    That's a cool concept. These rare protein-coding variations may be mostly unimportant to fitness today, and many are slightly deleterious. Still they provide a store of variability that increases the potential range of responses to future adaptive challenges. Or, they give us room to examine the effects of small differences, which will help us to understand better how genes work. For the past few thousand years, a small proportion of those have come under positive selection, the part that we have been studying in my lab since 2007.

    The current study has some drawbacks. For one, it isn't evident from the results how these new coding mutations are distributed among individuals. Under population growth alone, we should expect that the number of these new coding variants carried by any one individual should be approximately the same as any other individual, regardless of the population size. Where a big population differs from a small population is in the variety of mutations carried by different individuals, with the average number per individual being equal. That may be true in this study, but it isn't possible to tell from the results presented.

    To the extent that some of these mutations are deleterious, their distribution matters. In Europeans, there may be a greater number of deleterious mutations that are on average more rare; all things being equal, this pattern should make it harder to find statistical evidence for association of these rare variants with complex disorders. By contrast, in Africans, the higher average frequencies of such variants should make them easier to tie to phenotypic variation. All this can be concluded from frequencies alone, without a need to relate frequency to age.

    Probably the biggest shortcoming of the paper is in its estimation of ages for these rare mutational variants. Estimating the ages of mutations in human populations has been a real problem for those of us working with genotyping or sequencing data from small samples. When we depend on the linkage between a rare allele and nearby genetic loci, we run into a sampling problem: Estimating the proportion of recombinants in a population fundamentally has a lot of error when you are working with a sample of 10 copies of the rare allele.

    Estimating dates by LD is bad enough, but this paper doesn't even go that far. Instead, it estimates the ages of alleles from their frequency.

    Frequency estimation of age is OK if the genome sequences have come from a Wright-Fisher population (that is, a random-mating, constant size population). More common alleles tend to be older, new alleles tend to be very rare. This isn't a very accurate means of dating any particular mutation, because the relationship of age and frequency under genetic drift has a tremendous variance. But when pooling large sets of alleles into frequency classes, the age-by-frequency approach gives a rough idea of whether mutations have accelerated or stayed at a constant rate over time.

    But there's one obvious thing missing from the model that may have a large effect on the frequencies of rare coding variants: Introgression from Neandertals! If we want to know why Europeans have a large store of rare coding variants relative to Africans, their ancient mixture of a small fraction of a very divergent human population is one obvious reason. None of the Neandertal alleles in Europeans today are new, they are all old. But a method that estimates their ages by allele frequency alone will always conclude that these rare Neandertal alleles are very young.

    In the current paper, the relation of frequency and age is derived from simulations that are based on a model of human population history. Like all recent papers that apply a model of human population history, this one is both overcomplicated (lots of parameters to which we have no good estimates) and oversimplified (too few events to accommodate known historical phenomena). Here's the population model used to derive allele ages in the paper:

    Population model from Fu et al. 2012

    Population model from Figure S5 in the supplementary information from Fu et al. 2012

    The parameters for population divergence times and ancient population sizes are estimated from genetic data, so any systematic error will propagate through to the estimation of allele ages. The exclusion of Neandertal introgression in the model really does bias the allele age estimates badly, as Neandertal genes today are mostly rare, and mostly very old. This year's shift in our assumptions about mutation rates (to a much slower rate than previously assumed) will also affect the estimates of the demographic parameters in the model. An older coalescence time for most genes means a larger ancestral effective size for these populations, and much older allele ages when frequency is the estimator.

    Our lab is working very hard on allele ages, and I hope to be able to share some of that work soon.

    This study is not alone in demonstrating the real importance of rare coding variation in human populations. This line of research has substantial value, as it helps to show why so much of the additive genetic variation underlying variation in human phenotypes has not yet been assigned to genes. We know that many traits are heritable by comparing genetic relatives with each other. Finding the genetic loci that explain similarity among relatives is relatively easy when the genes involved are common, because the same gene variants will be shared across many families. But pooling many families doesn't help us find very rare mutations, as these are likely carried only by a few pedigrees even in a very large sample. By showing the large store of rare coding variation, these studies help to establish that much of the genetic variation underlying disease may be there for us to discover, if we change our discovery approach.

    References

    1. Fu W, O'Connor TD, Jun G, Kang HM, Abecasis G, Leal SM, Gabriel S, Altshuler D, Shendure J, Nickerson DA, et al. Analysis of 6,515 exomes reveals the recent origin of most human protein-coding variants. Nature. 2012.
    2. Hawks J, Wang ET, Cochran G, Harpending HC, Moyzis RK. Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences, U. S. A. [Internet]. 2007;104:20753–20758. Available from: http://dx.doi.org/10.1073/pnas.0707650104
    Tags: 
    recent evolution
    Europe
    Africa
    Holocene
    acceleration
    fitness effects
    mutation
    Synopsis: 
    Probing the pattern of noncoding rare variation in whole exome data.

  • Serbian Neolithic on display

    Tue, 2012-11-06 15:29 -- John Hawks

    Here's an interesting story for today:

    A hoard of jewelry, figurines and other objects crafted by early farmers in Serbia nearly 8,000 years ago is set to go on public display for the first time at a German museum. Archaeologists dug up the largely undisturbed stash of artifacts during excavations this summer at the site of a Neolithic settlement in Belica, Serbia, about 90 miles (140 kilometers) south of Belgrade.

    Tags: 
    Neolithic
    Serbia
    Europe

  • Dead Marshes in Denmark

    Thu, 2012-08-23 00:41 -- John Hawks

    ScienceNordic describes an incredible Iron Age archaeological dig in Denmark: "An entire army sacrificed in a bog".

    Archaeologists have spent all summer excavating a small sample of what has turned out to be a mass grave containing skeletal remains from more than 1,000 warriors, who were killed in battle some 2,000 years ago.

    ...

    The army beneath the bog may have been defeated and killed in a battlefield located far away from Alken Wetlands.

    Hertz says that if this were the case, it must have been a massive logistical task for Iron Age people to transport the bones to the lake.

    It's just like the Lord of the Rings! Ancient army that nobody remembers with bodies beneath the waters. Except, of course, these are bones. That sat on a battlefield to be ravaged by scavengers, and then secondarily tossed.

    Tags: 
    iron age
    Denmark
    Europe

  • Neandertal ancestry "Iced"

    Wed, 2012-08-15 15:24 -- John Hawks

    I've been mobbed with e-mails from readers asking about my reaction to the new paper by Anders Eriksson and Andrea Manica in PNAS, titled "Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins" [1]. The paper asserts that Neandertal similarity in the genomes of living people outside Africa can be explained only in terms of incomplete lineage sorting from the shared human-Neandertal common ancestral population in Africa. If the paper's assertions were accurate, we could go back to thinking that all the genetic heritage of people today traces back to Africa, although we would still need to abandon the idea that the African population had undergone a small bottleneck.

    I have not been posting as frequently the last month or two because I have been out of the country doing science.

    The new paper's press release has given rise to quite a lot of media attention, much of which unfortunately misrepresents our current knowledge of human and Neandertal genomes. Razib Khan summarized the situation on Monday, in a post titled, "Why you shouldn't publish in PNAS". I agree with his criticism, although I have a perspective coming out soon in PNAS. In fact, I suppose this episode shows why everyone should publish in PNAS, because so many journalists will just parrot press releases instead of asking relevant experts. Ewen Callaway did a great job on this story by putting it into the broader context ("Neandertal sex debate highlights benefits of pre-publication"). You will notice how no other science writers with any Neandertal knowledge picked up this press release...

    Paleoanthropology is a field where data are rare and precious, and we do a lot of arguing about the validity of models. I love arguing about the validity of models (Cliff Notes version: All models are wrong).

    Genomics is not such a field. We have abundant data today to compare with Neandertal genomes. Yet puzzlingly, the idea of Neandertal ancestry has been challenged by several papers that haven't performed any new empirical comparisons at all. I'm struggling to figure this out. We have an unparalleled ability to explore the genomes of humans and Neandertals, and we should believe a computer model with no empirical data?

    I've been assessing the Neandertal similarity of 1000 Genomes Project samples here on my blog (e.g., "Which population in the 1000 Genomes Project samples has the most Neandertal similarity?"). This is ongoing research here in my group, but we've been making it open because it tells us immediately that some hypotheses about Neandertal similarity must be wrong. Modeling is a lot of work. We're trying to avoid putting a lot of investment into modeling that will be easily refuted by the next piece of genomic data. Data are flowing now so rapidly that we can afford to be naive empiricists.

    For example, our comparisons quickly refute the hypothesis that Neandertal similarity comes only from ancient population structure in Africa. That hypothesis predicts much more heterogeneity within Africans in Neandertal similarity than exists today. We've shown that the heterogeneity in Africans is basically the same as within Europeans or Asians, and that the variance among African populations so far is quite small. Those are very simple observations, which are consistent with what Yang and colleagues [2] concluded on the basis of the frequency spectrum of Neandertal alleles in large samples of living people. Even though many Neandertal-shared SNP alleles came from incomplete lineage sorting, the signature of excess Neandertal sharing outside Africa must come mostly from recent introgression. In Ewen Callaway's article about this research, David Reich dismissed the new paper by Eriksson and Manica as "obsolete". I agree. The paper describes a model without carrying out any new empirical comparisons, and so has fallen behind where the science has gone.

    Another example is the proportion of Neandertal ancestry. Initially, the proportion of ancestry from Neandertals in living people was argued to be between 1 and 4 percent [3]. That was a model-based estimate that was the best possible under the assumption that Africans have no Neandertal ancestry. We now have a lot more human comparisons, which would make possible a more precise estimate of the mean. I hesitate to provide a new estimate, because we have shown that some Africans have substantial evidence of Neandertal similarity, which throws the baseline for any estimate into question. How much Neandertal ancestry is present in living people must depend on a more complex model of mixture among later populations. The result will still be small (probably less than 6 percent) but understanding this proportion will help us to evaluate when and where Neandertal genes flowed into our populations.

    Here's a third example. I haven't written about here yet, but I have been lecturing about it quite widely over the past few months. Earlier this year, the genome of Ötzi the Tyrolean Iceman was reported by Andreas Keller and colleagues [4]. Aaron Sams and I downloaded the data and have been carrying out several different kinds of comparisons. A picture:

    Otzi 1000 Genomes Neandertal comparison

    I'd like to see the model of African population structure that could explain this result...

    If you'll remember my earlier posts on the 1000 Genomes Project samples, this chart is a histogram of the number of shared Neandertal derived SNP alleles in different samples. The European and Asian samples are substantially greater than either African sample (here, Luhya and Yoruba colored differently). If we took as a baseline that Europeans have an average of 3.5 percent Neandertal, Ötzi would have around 5.5 percent (again, the actual percentage would be highly model-dependent). He has substantially greater sharing with Neandertals than any other recent person we have ever examined.

    You can imagine, we have carried out just about every comparison we can think that could explain this result as anything other than greater Neandertal ancestry. Aaron and I will be putting our manuscript on the arXiv as soon as we've both signed off on all the text and figures, hopefully this week. This is simple stuff, and I see no reason not to be open about it -- anybody with the Ötzi data can immediately do the same thing.

    We think that showing and sharing these comparisons will save people a lot of useless effort. Personally, I can't believe that these people spending effort on population models for Neandertals aren't talking to those of us who have already carried out these comparisons and have already presented them in public. I guess we'll find out if secrecy or openness leads to better science.

    Meanwhile, I can share the abstract of the conference paper I'll be presenting in September at the meeting of the European Society of Human Evolution in Bordeaux:

    Evaluating recent evolution, migration and Neandertal ancestry in the Tyrolean Iceman

    Paleogenetic evidence from Neandertals, the Neolithic and other eras has the potential to transform our knowledge of human population dynamics. Previous work has established the level of contribution of Neandertals to living human populations. Here, I consider data from the Tyrolean Iceman. The genome of this Neolithic-era individual shows a substantially higher degree of Ne- andertal ancestry than living Europeans. This comparison suggests that early Upper Paleolithic Europeans may have mixed with Neandertals to a greater degree than other modern human populations. I also use this genome to evaluate the pattern of selection in post-Neolithic Europeans. In large part, the evidence of selection from living people’s genetic data is confirmed by this specimen, but in some cases selection may be disproved by the Iceman’s genotypes. Neolithic-living human comparisons provide information about migration and diffusion of genes into Europe. I compare these data to the situation within Neandertals, and the transition of Neandertals to Upper Paleolithic populations – three demographic transitions in Europe that generated strong genetic disequi- libria in successive populations.

    References

    1. Eriksson A, Manica A. Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins. Proceedings of the National Academy of Sciences. 2012.
    2. Yang MA, Malaspinas A-S, Durand EY, Slatkin M. Ancient structure in Africa unlikely to explain Neanderthal and non-African genetic similarity. Molecular biology and evolution. 2012.
    3. Green RE, Krause J, Briggs AW, Maricic T, Stenzel U, Kircher M, Patterson N, Li H, Zhai W, Fritz MH, et al. A Draft Sequence of the Neandertal Genome. Science [Internet]. 2010;328:710–722. Available from: http://dx.doi.org/10.1126/science.1188021
    4. Keller A, Graefen A, Ball M, Matzas M, Boisguerin V, Maixner F, Leidinger P, Backes C, Khairat R, Forster M, et al. New insights into the Tyrolean Iceman's origin and phenotype as inferred by whole-genome sequencing. Nature communications. 2012;3:698.
    Tags: 
    Neandertal DNA
    Otzi
    ancient DNA
    Neolithic
    Europe
    introgression
    gene flow
    population structure
    modeling
    metascience

  • Ceramics in the Epigravettian of Croatia

    Tue, 2012-07-31 11:19 -- John Hawks

    I've had a paper on my desktop for more than a week expecting to write a comment on it, and now happily I discover that the first author, Becky Farbstein, has described the work in a blog post: "First Epigravettian Ceramics in Europe". The paper [1] describes ceramic figurines from 12,000-15,000 years ago in Croatia -- not the earliest instance of ceramic technology in the world, but one of three very early instances that suggest a pattern:

    There are major implications for the rapidly accumulating body of evidence of both artistic and functional ceramics in pre-Neolithic contexts (remember this post?), but most importantly, we can no longer equate ceramic technologies with sedentary societies. The finds from Vela Spila encourage us to reconsider our ideas about the multiple inventions and diverse roles of ceramics throughout prehistory. Clearly, in lots of different places across Eurasia, throughout the late Palaeolithic, people were experimenting with ceramic materials, intentionally firing them, and developing new artistic traditions associated with their innovations. Ceramics should not necessarily be considered an anachronism (or contamination) when found in Palaeolithic horizons.

    I love it when I can read about work from the authors, and hope more and more people will take up this challenge!

    References

    1. Farbstein R, Radić D, Brajković D, Miracle PT. First Epigravettian Ceramic Figurines from Europe (Vela Spila, Croatia) Petraglia MD. PLoS ONE [Internet]. 2012;7(7):e41437. Available from: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0041437
    Tags: 
    blogging
    technology
    Epigravettian
    Upper Paleolithic
    Europe

  • LRJ as a transitional industry

    Wed, 2012-07-04 09:52 -- John Hawks

    I was reading this morning an interesting paper from last year by Damien Flas [1], who considered the context of archaeological assemblages grouped as Lincombian-Ranisian-Jerzmanowician industry in northern Europe. This awkwardly-named archaeological grouping is one of the "transitional" initial Upper Paleolithic industries of Europe, plausibly made by Neandertals but involving artifacts built on a blade-based reduction strategy.

    Flas tentatively concludes that LRJ was produced by Neandertals, mainly because of its early date, the late appearance of Aurignacian in northwestern Europe, and the lack of technical connections to traditions that were plausibly made by modern humans. I will share the portion of the text where he discusses the lack of such links:

    Recently, maybe because an acculturation process related to the Aurignacian complex has been challenged on the basis of chronological and stratigraphic data (e.g. Bordes 2003; d'Errico et al. 1998; Zilhão 2006a), other industries have been proposed as proxies for the spread of AMH and as acculturators driving the last Neanderthals to develop the ‘transitional industries’ (Bar-Yosef 2007; Hoffecker 2009; Mellars 2005). In Central Europe, the Bohunician has been seen as a complex related to the spread of AMH from the Near East (Bar-Yosef and Svoboda 2003; Kozłowski 2004). Indeed, it shows similarities with the assemblages in layers 1–2 of Boker-Tachtit (Skrdla 2003; Tostevin 2003), and Tostevin (2007) has set out in a detailed way how the Szeletian assemblage from Vedrovice V may be seen as the result of acculturation of the local Middle Paleolithic (Keilmessergruppe from Kulna Cave) by the Bohunician complex.

    However, the extension of this model to include a scenario whereby LRJ Neanderthals are acculturated by Bohunician AMH finds little support in the evidence, and is thus a weak hypothesis. There are no human remains, either in the Near East or in Central Europe, showing that this ‘Emireo-Bohunician’ complex is made by AMH, and it could alternatively correspond to the diffusion of technical ideas rather than to a population dispersal (Tostevin 2003). Moreover, the relationship between Boker Tachtit (in the Negev) and the Bohunician (in Moravia) is based on technological similarities, but intermediary assemblages between these two distant regions are rare (Bar-Yosef and Svoboda 2003; Kozłowski 2004) and sometimes show variability (as at Temnata and Bacho Kiro: Teyssandier 2008; Tsanova 2008). It would be also necessary to assess other European late Middle Paleolithic industries that could potentially play a role in the emergence of the Bohunician (Kozłowski 2001), such as the Polish sites of Piekary IIa and Ksiecia Jozefa (Sitlivy et al. 2007a, 2007b; Zilhão 2006a), as well as Korolevo I/IIb (Ukrainia: Monigal et al. 2006) and the Bulgarian Moustero-Levalloisian with leaf-points of Samuilitsa and Muselievo (Tsanova 2008). Even if the hypothesis that the Bohunician corresponds to an AMH dispersal from the Near East is accepted, the LRJ shows different objectives and reduction strategies from the Bohunician. More generally, it is difficult to see any lithic innovations in Bachokirian or Bohunician industries that could provide the stimulus for long-distance acculturation.

    He posits a transformation from some Mousterian variant, based on the specialization toward "laminar blanks" (that is, cores suitable for striking blades). I find very interesting the implication of information exchange and possible dispersal among late Neandertals in the northern tier of Europe.

    Related: my post from last year on Kent's Cavern dating, "The radiocarbon dating paper without a radiocarbon date". The Kent's Cavern maxilla overlies some artifacts attributed to LRJ traditions.

    References

    1. Flas D. The Middle to Upper Paleolithic transition in Northern Europe: the Lincombian-Ranisian-Jerzmanowician and the issue of acculturation of the last Neanderthals. World Archaeology. 2011;43(4):605 - 627.
    Tags: 
    Middle Paleolithic
    Neandertals
    LRJ
    Britain
    Europe
    population dynamics
    archaeology

  • Reindeer hides and Neandertals

    Sun, 2012-06-24 10:08 -- John Hawks

    In reference to the post below about Quina Mousterian and reindeer specialization ("Paleoclimate and shifting Neandertal strategies"), let me add this great quote from Mark White. He addresses himself to the question of what kinds of strategies Neandertals employed against the cold of the MIS 4 winter in Britain and France.

    Aiello and Wheeler hypothesize a very conservative 1 clo of insulation. The pelts of exploited Pleistocene mammals would have greatly exceeded this level (cf. Stenton 1991: 11), meaning that a clothed Neanderthal could have remained comfortable at temperatures far below those outlined above. Reindeer hides are particularly valued by modern arctic peoples because they are lightweight and their fur has excellent insulatory properties (clo value = 7: ibid.). The best time to procure reindeer hides is in the late summer, prior to the development of the heavy winter pelage and after the skin had repaired the damage caused by any summer parasites (ibid.: 6), which adds another interpretative dimension to the autumn mass killing of reindeer at Salzgitter-Liebenstedt (Gaudzinski and Roebroeks 2000); especially if Bocherens et al. (2005) are correct in their assertion that northern Neanderthals ate a lot of mammoth and rhino, but little reindeer (the reverse being true for hyenas). One wonders whether some species were targeted as much for their hides and sinews as for their meat value (see Burch (1998) for caribou), and whether the classic ‘scavenging’ pattern of heads and lower limbs found in Middle Palaeolithic sites is in fact a signature testifying to the preferential transport of hides away from the kill sites (cf. Chase 1986; Mellars 1996). Indeed, such patterns find obvious parallels in medieval tanneries (Serjeantson 1989; Gidney 2000). The broad association of scraper-rich Quina assemblages with colder environments and reindeer bones is highly suggestive in this regard (cf. Mellars 1996: 329; Dibble and Rolland 1992).

    The quote is from another paper with an awesome title, "Things to do in Doggerland when you're dead" [1]. He adds that in Britain a a major limitation on Neandertals may have been the lack of wood -- not only for fire, but also for construction of long implements such as spears. The evidence for woodworking at some sites suggests they may have been located near stands of trees that persisted during the spread of periglacial steppes. All in all, it's a very interesting paper.

    References

    1. White MJ. Things to do in Doggerland when you're dead: surviving OIS3 at the northwestern-most fringe of Middle Palaeolithic Europe. World Archaeology. 2006;38(4):547 - 575.
    Tags: 
    hunting
    Neandertals
    Britain
    Europe
    Middle Paleolithic
    fauna

  • Neandertals and eagle talons

    Mon, 2012-03-12 00:31 -- John Hawks

    Eugène Morin and Véronique Laroulandie have published a new paper in PLoS ONE demonstrating evidence that some Neandertals had a fetish for eagle talons [1]. From the conclusion of the (open access) paper:

    Because claws are inedible, the specimens presented here are not compatible with human consumption. This means that the tool-marked terminal phalanges found at Combe-Grenal, Les Fieux, Pech de l'Azé IV, and Grotta di Fumane were likely used as tools and/or as items of symbolic expression. Although the sample size is small, the fact that all the terminal phalanges that show cutmarks are from eagles argues against their utilization in strictly non-symbolic contexts. This last pattern is noteworthy because eagles are among the rarest birds in the environment, a pattern explained by their high trophic position in the food web [31]. This bias toward large and powerful diurnal raptors possibly indicates that the claws were used in symbolically-oriented contexts by Neanderthals, although the latter contexts remain to be more precisely defined. One possibility is that they were used as ornaments, as has been suggested for the Upper Paleolithic occupations (dated to ca. 20 ka) at Meged Rockshelter in Israel [32].

    This is reminiscent of last year's paper about intentional feather removal from raptor wings at Fumane Cave, Italy [2]. Morin and Laroulandie provide a table listing evidence of cut marked bird remains from Middle Paleolithic contexts across Europe. More and more, we are seeing these kinds of lists, as zooarchaeologists are synthesizing the behavior patterns evidenced by low frequency faunal remains from many sites.

    Raptor phalanges showing Neandertal cutmarks

    Figure 2 from Morin and Laroulandie, 2012. Original caption: "Stone tool incisions on terminal phalanges of diurnal raptors from Middle Paleolithic occupations in France. A) example of a fully fleshed golden eagle digit. B–G show cutmarked terminal phalanges from layer 52 at Combe-Grenal (B–C, golden eagle) and layers Jbase (D–E, white-tailed eagle) and I/J (F–G, white-tailed eagle) at Les Fieux. The black bars correspond to 1 cm. Philippe Jugie took the Combe-Grenal photographs, the others were taken by V.L."

    Unambiguous evidence for ornamentation by some Neandertals has long been known, but adding more clear evidence for the use of perishable materials helps to establish the pattern. More important, the present evidence from Combe Grenal puts the non dietary use of eagle talons back to 90,000 years ago, long before any Upper Paleolithic in the area. It's one thing when archaeologists document symbolic behavior in "transitional industries", because these arguably represent a more advanced conception of technology in some way. I am more interested in the recent expansion of our understanding Mousterian and similar industries in Europe.

    References

    1. Morin E, Laroulandie V. Presumed symbolic use of diurnal raptors by Neanderthals. PloS one. 2012;7(3):e32856.
    2. Peresani M, Fiore I, Gala M, Romandini M, Tagliacozzo A. Late Neandertals and the intentional removal of feathers as evidenced from bird bone taphonomy at Fumane Cave 44 ky B.P., Italy. Proceedings of the National Academy of Sciences [Internet]. 2011;108:3888–3893. Available from: http://dx.doi.org/10.1073/pnas.1016212108
    Tags: 
    Neandertals
    symbolic behavior
    Mousterian
    Combe Grenal
    France
    Europe

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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

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Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.