Anthropology.net

This is a quick note to point readers in the direction of several posts that have appeared online in recent days, on the origins and spread of agriculture, and the part language may have played in the process,  in Europe, Asia and the Americas. Although I’ve recently concentrated on writing about our Palaeolithic origins, if there’s one behavioural trait that separates modern humanity from its archaic counterpart, the widespread adoption of agriculture over the past ten millennia has set us far apart from all that went before, and is more directly responsible for our urbanised civilisation and attendant corporate woes than anything else that presently comes to mind. Moreover, and beyond our city walls, the devastating impact of agriculture on rural landscapes worldwide is a problem that concerns us all, with for example, the clearance of the Amazon rain-forest for cattle a particular thorn in our side, whilst our growing appetite for bio-fuels looks set to have no less a deadly impact as we turn even more land over to the growing of necessary crops.

First up is this post at Gene Expression, European man perhaps a Middle Eastern farmer, in which Razib Khan discusses the findings of a recent paper at PLoS Biology, A Predominantly Neolithic Origin for European Paternal Lineages – for which this is the abstract:

The relative contributions to modern European populations of Paleolithic hunter-gatherers and Neolithic farmers from the Near East have been intensely debated. Haplogroup R1b1b2 (R-M269) is the commonest European Y-chromosomal lineage, increasing in frequency from east to west, and carried by 110 million European men. Previous studies suggested a Paleolithic origin, but here we show that the geographical distribution of its microsatellite diversity is best explained by spread from a single source in the Near East via Anatolia during the Neolithic.

Taken with evidence on the origins of other haplogroups, this indicates that most European Y chromosomes originate in the Neolithic expansion. This reinterpretation makes Europe a prime example of how technological and cultural change is linked with the expansion of a Y-chromosomal lineage, and the contrast of this pattern with that shown by maternally inherited mitochondrial DNA suggests a unique role for males in the transition.

Razib offers some background to the ongoing debate…

For the past few decades there has been a long standing debate as to the origins of modern Europeans. The two alternative hypotheses are:

* Europeans are descended from Middle Eastern farmers, who brought their Neolithic cultural toolkit less than 10,000 years ago.

* Europeans are descended from Paleolithic hunter-gatherers, who acculturated to the farming way of life through diffusion of ideas.

…and further notes:

In this unsettled landscape comes a new paper which turns some assumptions about Y chromosomal variation in Europe on its head. The focus is on a subclade of the R1b haplogroup, which has its highest frequencies in Western Europe, in particular along the Atlantic fringe. The pattern of variation has led many to infer that this lineage, in particular the R1b1b2 haplgroup, is a marker of the Paleolithic populations of Western Europe. The high frequency of this marker among the Basques in particular is seen as evidence of this, because this group speaks a language which is a pre-Indo-European isolate (the Basques are used as a Paleolithic reference group in many papers). But perhaps not…

…One issue to note is that it seems likely that if the model presented here is true, that R1b1b2 is newcomer from the Middle East which rapidly expanded in frequency across Western Europe, it’s going to be hard to getting the clarity you need from molecular clock based methods because the demographic processes occurred rather rapidly. We know from archaeology that agricultural societies could sprout up almost instantaneously, as if they simply transplanted their culture to new locales. Some of this likely occurred via sea, using the Mediterranean and the Atlantic fringe…

…The authors point out that in places like Japan and India there is a great deal of circumstantial evidence for agriculture resulting in the expansion of particular lineages, so the preponderance of acculturation in Europe as the mode of transmission seems atypical…

…One analog might be the emergence of mestizos in the New World, who have predominantly European male lineages and native female lineages. Finally, one question a friend brought up: if the higher frequency of R1b1b2 is a function of the wave of advance, why is it the same haplogroup all along the wave front? Standard population genetic theory tells us that fragmented small groups will tend to lose genetic diversity and fix particular alleles, but those alleles are not going to be the same. It seems that it is more plausible that there were serial bottlenecks through coastal migrations, and eventually these expanded inland once they stumbled onto the northwest European plain. But that’s just speculation.

For further discussion, please see Dieneke’s whileYann Klimentidis mentions both this paper and another, namely Genetic discontinuity between local hunter-gatherers and central Europe’s first farmers.

Next it’s over to Gambler’s House, and an article titled The Supposed Linguistic Evidence for the Spread of Agriculture, whose introductory notes state the following:

The prehistoric peoples of the American Southwest were agriculturalists.  Different societies may have calibrated their mix of farming, hunting, and gathering differently, but they all seem to have done all three eventually, and for most it’s quite apparent in the archaeological record that farming was the predominant method of subsistence.  The crops they grew were corn, beans, and squash, the classic triad of North American agriculture.  These plants are not native to the Southwest, however, so they must have been introduced at some point from Mesoamerica, where they originated.  The introduction of corn, in particular, must have also involved the introduction of agricultural techniques, since it can’t grow without help from humans.  All this is pretty uncontroversial among Southwestern archaeologists.

The nature of the introduction of agriculture, however, has been a point of more dispute.  The main arguments have to do with how long it took after the introduction of maize for the societies growing it to become totally dependent on it and thus become primarily agriculturalists rather than hunter-gatherers.  One view, espoused by Chip Wills at UNM, sees the introduction of corn as being gradual, perhaps filtering up from one hunter-gatherer group to another, and increasing dependence on it as taking place in the context of hunter-gatherer subsistence decisions and environmental fluctuations, with the total switch to a fully agricultural lifestyle not taking place until maybe as late as the Pueblo II period.  The other view, associated most strongly with R. G. Matson of the University of British Columbia, sees the introduction of maize as having been rapid and involving a totally different lifestyle from Archaic hunter-gatherers from the get-go.

There follows an in-depth discussion of the theories of Australian Professor of Archaeology, Peter Bellwood, who contends that…

… the enormous geographical extent of some language families by associating them with the spread of particular agricultural traditions.  This has been somewhat controversial, particularly in regard to Indo-European, as it produces a very specific answer (given Bellwood’s specific assumptions) to the vexing question of where a given language family originated, often called its Urheimat.  Since Bellwood argues that hunter-gatherers are unlikely to adopt agriculture, whether on their own or when exposed to it by contact with farming groups, his model predicts that the Urheimat of a given language family must be somewhere in the region where its agricultural tradition originated.  For Indo-European this means the Fertile Crescent rather than the Eurasian Steppe, which has been the preferred answer for many Indo-Europeanists on various grounds.  This has led to much controversy.

And continuing the language thread, we return to Gene Expression, where another article, Complex societies = simple languages, goes on to discuss a paper at PLoS ONE, Language Structure Is Partly Determined by Social Structure, for which this is the introduction:

Although the largest languages are spoken by millions of people spread over vast geographic areas, most languages are spoken by relatively few individuals over comparatively small areas. The median number of speakers for the 6,912 languages catalogued by the Ethnologue is only 7,000, compared to the mean of over 828,000 [1]. Similarly, for the 2,236 languages in our sample (Figure 1), the median area over which a language is spoken is about the size of Luxembourg or San Diego, California (948 km²). The mean area is about the size of Austria or the US state of Maryland (33,795 km²).

Languages also differ dramatically in the proportion of individuals who speak the language natively (L1 speakers) to those who learned it later in life (L2 speakers) (Table S1). Although there are numerous counter-examples (Text S1), languages spoken by millions of people have a greater likelihood of coming into contact with other languages and of having numerous nonnative speakers compared to languages spoken by only a few thousand people.

This is not surprising: a language spoken by more people is more likely to encompass a larger and more diverse area and include speakers from varying ethnic and linguistic backgrounds. Conversely, languages spoken by a thousand or even fewer individuals tend to be spoken in highly circumscribed locales (Text S2). Overall, languages with smaller speaker populations are more likely to be spoken by more socially cohesive groups [2] than languages that have millions of speakers.

And by a curious coincidence, news comes to today of the Evolang 2010 Conference due to take place in Utrecht, Netherlands, between this coming April, 14-17th.

To finish up, there’s a nice post over at PaleoFuture, The Victory of Chemistry over Agriculture, which begins by noting:

To many people of the year 2010 the 1953 book, The Road to Abundance, is a heretical, nightmarish vision of the future. Chemicals and factory farming are seen as the logical next step in the evolution of food production for mankind.  Jacob Rosin, co-writing with Max Eastman, describes the eventual “victory of chemistry over agriculture,” and mankind’s “bondage to the planet.”

The ultimate goal of Rosin’s ambition was to be “more efficient than nature.” In his advocacy of a completely synthetic diet Rosin called into question both the definition and the benefit of “natural foods.”

See also: Telegraph – Giant Cattle to be Bred back from Extinction – via John Hawks

This post in turn links to another, “Factory” Farms of the Future (1961) from which the image at top is taken.

References:

Balaresque P, Bowden GR, Adams SM, Leung H-Y, King TE, et al. (2010) A Predominantly Neolithic Origin for European Paternal Lineages. PLoS Biol 8(1): e1000285. doi:10.1371/journal.pbio.1000285

Genetic discontinuity between local hunter-gatherers and central Europe’s first farmers.
Bramanti B, Thomas MG, Haak W, Unterlaender M, Jores P, Tambets K, Antanaitis-Jacobs I, Haidle MN, Jankauskas R, Kind CJ, Lueth F, Terberger T, Hiller J, Matsumura S, Forster P, Burger J.
Science 2009 Oct 2;326(5949):137-40.

Lupyan G, Dale R (2010) Language Structure Is Partly Determined by Social Structure. PLoS ONE 5(1): e8559. doi:10.1371/journal.pone.0008559

I’ve recently commented on the PBS documentary series opener of The Human Spark – Becoming Us, the majority of which struck me as being out of date and out of touch, with far too much emphasis being placed on looking for specious differences between anatomically modern humans and Neanderthals co-habiting in Late Middle – Early Upper Palaeolithic Europe, as Alan Alda and his chosen guests set out to reinforce most of the worn-out, stereotypical views that pitted the supposedly ingenious AMH against their allegedly half-witted Neanderthal cousins.

However, even in the worst documentaries there’s usually the odd gem secreted within, and Becoming Us proved no exception, as in Chapter 4, the focus turned from Europe to Africa, where we met up with Professor Alison Brooks (see also) and her team of researchers at three sites – one of which was Olorgesailie, located near Lake Magadi in the Eastern Rift Valley of Kenya. Over many years of excavations, they have uncovered strong evidence to suggest that much of what is credited to AMH behavioural modernity in UP Europe, actually began tens if not hundreds of thousands of years earlier in Africa  – as noted amongst others by Bednarik, whose prodigious output over the years has suggested exactly the same sorts of ideas. I for one had somehow completely missed out on, forgotten about, or just overlooked this particular story, so a big hat-tip to the documentary for this alone. Although I think it would have been better had this section of the film been placed much nearer the beginning, the fact it was included at all came as a welcome relief to what had gone before.

To watch this excerpt, click the link and move the video-player slider to around the 11-minutes-remaining mark.

Next up,  here’s  the abstract of a paper which Brooks co-authored in 1999 with Sally Mcbrearty – for full access you can opt for the $53 plus tax version (53 bucks and more – for a paper – seriously?), the $19.95 version here, or if money’s not your thing, there’s a free (PDF) reproduction right here.

Abstract:

Proponents of the model known as the “human revolution” claim that modern human behaviors arose suddenly, and nearly simultaneously, throughout the Old World ca. 40–50 ka. This fundamental behavioral shift is purported to signal a cognitive advance, a possible reorganization of the brain, and the origin of language. Because the earliest modern human fossils, Homo sapiens sensu stricto, are found in Africa and the adjacent region of the Levant at >100 ka, the “human revolution” model creates a time lag between the appearance of anatomical modernity and perceived behavioral modernity, and creates the impression that the earliest modern Africans were behaviorally primitive.

This view of events stems from a profound Eurocentric bias and a failure to appreciate the depth and breadth of the African archaeological record. In fact, many of the components of the “human revolution” claimed to appear at 40–50 ka are found in the African Middle Stone Age tens of thousands of years earlier. These features include blade and microlithic technology, bone tools, increased geographic range, specialized hunting, the use of aquatic resources, long distance trade, systematic processing and use of pigment, and art and decoration.

These items do not occur suddenly together as predicted by the “human revolution” model, but at sites that are widely separated in space and time. This suggests a gradual assembling of the package of modern human behaviors in Africa, and its later export to other regions of the Old World. The African Middle and early Late Pleistocene hominid fossil record is fairly continuous and in it can be recognized a number of probably distinct species that provide plausible ancestors for H. sapiens.

The appearance of Middle Stone Age technology and the first signs of modern behavior coincide with the appearance of fossils that have been attributed to H. helmei, suggesting the behavior of H. helmei is distinct from that of earlier hominid species and quite similar to that of modern people. If on anatomical and behavioral grounds H. helmei is sunk into H. sapiens, the origin of our species is linked with the appearance of Middle Stone Age technology at 250–300 ka.

This is a pretty long paper, with much of the data presented in tables that you need to tilt your head sideways to read at a right angle, (unless you print it out), and for the time being I’ll refrain from commenting further till I’ve had time to read it properly through – I don’t know for how long the free PDF version will remain online, so my advice would be to grab it now. Suffice it to say though, it’s packed with information, and there’s a very well written and thoughtful conclusion that at one point goes so far as to exhort Africanist researchers to consider that these early innovative behaviours dating back over 200,000 years may themselves have directly prompted morphological changes to early humans as they evolved into what we refer to as anatomically modern.

See also: Center For the Study of Human Origins, New York University

Reference:

The Revolution that Wasn’t: A New Interpretation of the Origin of Modern Human Behavior – by Sally Mcbrearty and Alison S. Brooks, Journal of Human Evolution, Volume 39, Number 5, November 2000 , pp. 453-563(111) doi:10.1006/jhev.2000.0435

A Very Remote Period Indeed: Paleolithic radiocarbon legerdemain

Science Now: Radiocarbon Daters Tune Up Their Time Machine

Two articles of note on the subject of carbon dating have appeared over the past week, the first of which looks at the way in which in which some online writers – myself included, I’m afraid – don’t always give correct dates when considering radiocarbon years and calendar years, with the result that the order in which events occurred, or how artefacts and remains are placed in their Late Middle and Upper Palaeolithic context, can by default, be misleading. For the sake of space and brevity I’ve included a couple of extracts from both posts, but needless to say, both are worth reading in their entirety.

First we hear from Asst. Professor Julien Riel-Salvatore, who writes thus:

Two fundamental but often underappreciated aspects of radiocarbon dating concern the ages it yields and the fact that these ages need to be calibrated in order to get an age that can be expressed in calendar years. I say these aspects are underappreciated because of the way radiocarbon age determinations are usually reported in news reports and, more rarely, in actual research papers.

First, age determinations. Radiocarbon dating is based on the observation that given 14C in previously living organisms decays at a constant, predictable rate. In this case, half of a sample’s 14C decays in about 5730 years in exponential fashion. This means, that after 5730 years, 1/2 of the 14C of a previously living organism remain, 1/4 remains after 11,460 years, etc. The uncertainty or error range reported for all radiocarbon dates is due to imprecision in counting the radioactive decay of carbon atoms in a sample, and it is a critical component of the date.

What the error range indicates is a 66% chance that the age of a sample falls within the interval it brackets. Double the error range, and the resulting interval is 95% likely to include it. What is important to note is that raw radiocarbon age ranges are centered on the date that is statistically most likely to be the correct one for a dated sample. In that sense, it is somewhat warranted to use the date as a shorthand to discuss how old a sample is.

That is, for a bone point dated to 13,400 +/- 100BP (these dates are expressed as before present, with the present assumed to be 1950), it is technically OK to say that it is a 13,400 year-old point, since that age is the most likely to be correct within the interval defined by the error range.

The problem, however, is that radiocarbon years don’t correspond to calendar years, and usually underestimate the true age range of any given sample. This is because the concentration of atmospheric radiocarbon has not been constant over time. However, this problem can be corrected through the use of calibration curves based on the radiocarbon dating of samples of known age and extrapolated from the discrepancy between the two ages. Samples whose calendar age can be determined include historical artifacts, as well as organic remains that grow or accumulate in yearly increments, such as trees (that accumulated a new grwoth ring yearly) or corals.

This is particularly important when considering the chronology of the late Neanderthals, their disappearance from the fossil record, and the implications that may arise therefrom. However, the fact remains that there is apparently good evidence to suggest that Neanderthals survived even longer than traditionally believed, and I’ll try and re-address some of this in a later post in a more accurate way than I’ve done so far.

Next, we hear from Michael Balter, who begins his post by saying:

It took nearly 30 years and a lot of heated debate, but a team of researchers has finally produced what archaeologists, geologists, and other scientists have long been waiting for: a calibration curve that allows radiocarbon dating to achieve its full potential. The new curve, which now extends back 50,000 years, could help researchers work out key questions in human evolution, such as the effect of climate change on human adaptation and migrations.

The basic principle of radiocarbon dating is fairly simple. Plants and animals absorb trace amounts of radioactive carbon-14 from carbon dioxide (CO₂) in the atmosphere while they are alive but stop doing so when they die. The steady decay of carbon-14 from archaeological and geological samples ticks away like a clock, and the amount of radioactive carbon left in the sample gives a reproducible indication of how old it is. Most experts consider the technical limit of radiocarbon dating to be about 50,000 years, after which there is too little carbon-14 left to measure accurately.

And follows on by relating:

More recently, however, thanks to new and more accurate data from foraminifers, corals, and other sources–plus some fancy statistical treatments that help predict which way data gaps bend the curve–the INTCAL group has been able to resolve most of the discrepancies. “It took the group quite a while to come together and agree,” says INTCAL team leader Paula Reimer, a geochronologist at Queen’s University Belfast in Northern Ireland.

But the new data, combined with what Reimer calls a “real sense of necessity” among team members to resolve the debates, won the day.  The new curve, called INTCAL09 and published this week in the journal Radiocarbon, not only extends radiocarbon calibration to 50,000 years ago but also considerably improves the earlier parts of the curve, researchers say.  Getting those dates right is critical to understanding such questions as whether humans began painting caves when the climate was colder or warmer, says Clive Gamble, an archaeologist at the University of London, Royal Holloway.

For example, the raw radiocarbon dates for the spectacular paintings of horses, lions, bison, and other animals at Chauvet Cave in southern France, the oldest known cave art, come out at 32,000 years ago, right after a major cold spell hit Europe; but the new calibration curve makes the earliest paintings at Chauvet 36,500 years old, a period of relative warmth.

So the paintings at Chauvet appear to be much older than originally predicted, extending the era of cave painting by around 4 millennia, and by a handy coincidence, there is another post at AVRPI which looks at the dating of the decorated fragments found at Fumane Cave, previously dated to around 36 kya,  in Italy:

The main issue, chronologically speaking, has been to determine when the figures were painted on the cave vault, since the layers in which they were recovered only provide a terminus ante quem for their age, in other words, an upper limit for their age.

So, at first glance, there is no evidence for the age of these paintings beyond that of the layers in which they were recovered. However, in this study, Broglio et al. (2009) make the case that all the paintings date to the earliest Aurignacian at the site, that is to level A2. Historically, the dating of the earliest Aurignacian at Fumane has been hotly debated, but the authors present new dates for previously dated charcoal samples that have undergone, for the new dates, a new, more thorough pretreatment (i.e., ABOx SC).

This has provided two statistically equivalent age determinations of 35,640 +/- 220 and 35,180 +/- 220 BP for level A2. Interestingly, and fittingly in light of my recent post on the presentation of calibrated and uncalibrated radiocarbon dates, they conclude that, by reference to the calibration curve based on the Cariaco Basin data and the GISP2 Greenland ice core, that “the chronological data show that Protoaurignacian Unit A2 dates to between 43,250 to 40,500 BPGISP2, with an age of 41,000BPGISP2 being statistically more likely” (Broglio et al. 2009:760; my translation, emphasis added).

Back for a final word from John Hoffecker via Michael Balter:

And John Hoffecker, an archaeologist at the University of Colorado, Boulder, says that the data sets behind the new curve will allow a more-precise correlation between radiocarbon dates and prehistoric climate reconstructions based on Greenland ice cores and other proxy indicators of ancient weather.

Even before the adoption of the new curve, Hoffecker says, those data sets were suggesting that modern humans had moved into Europe about 45,000 calibrated years ago, much earlier than previously thought–and early enough for them to have had substantial contact with Neandertals over thousands of years.  Although the new curve is a major landmark, it is “definitely not the last word” in radiocarbon calibration, Reimer says. Her team is already planning an update for 2011, “as we learn more about the Earth’s carbon reservoirs and how they changed over time.”

If we have AMH in Europe by 45 kya, and Neanderthals living in the same place till around 20-25  kya, we’re looking at a co-existence of the two peoples that lasted between 20,000 and 25,000 years. Recent research on pigmented shells in Spain dating to c.50 kya has now blown away the idea that Neanderthals didn’t have the cognitive capacity for symbolic representation, and indicates to me at least that we’re in for a few more surprises – for example I find it hard to believe that no Neanderthal ever daubed paint with intent on a cave wall, or passed on the occasional fashion tip to the arriviste moderns.

So although I might not go so far to say that ‘they were us and we were them’, but I’m of the firm opinion that to deny the likelihood that Neanderthals and AMH exchanged more than sultry looks across nocturnal camp-fires, seems increasingly mistaken, especially given around 20,000 years with time on their hands.

Increased accuracy from radiocarbon dating should help pinpoint more clearly the exact chronology of what is known so far, while further discoveries will doubtless cause more controversy still, but the overall trend of news points us toward a greatly more complex situation in the MP and UP than evidenced by ‘The Human Spark – Becoming Us’, viewable in full over at PBS;  made in 2008, it clearly illustrates how out of touch many researchers were back then, and to some extent, probably still are.

image: Fumane Cave

The Committee for Skeptical Inquiry have just announced the following, regarding the catastrophic earthquake that has wrought untold devastation on the population of Haiti, where tens of thousands are estimated to have died, with another 3 million people said to be adversely affected.

The Center for Inquiry is accepting disaster-relief donations through its S.H.A.R.E. program to support those providing care to the survivors of the 7.0 earthquake that struck Jan. 12 near the capital city of Port-au-Prince, Haiti.

All donations—100 percent with no operating costs retained—will be sent directly to the secular aid group Doctors Without Borders, which suffered the loss of all three of its medical facilities and is working against difficulties to provide the basics of first-aid care and stabilization.

The needs of those who’ve lost their family members, their homes, and their livelihoods will be very great. Your assistance will make a huge difference for the victims of this tragic disaster. Please join us and other humanists and skeptics as we help those in need in this time of crisis.

A contribution of any amount would be greatly appreciated by everyone at the Center for Inquiry. Thank you for your continued support of our work, and please consider a donation to S.H.A.R.E. in honor of those in Haiti who need help.

Please make your contribution to S.H.A.R.E. directly by clicking here. All funds sent to S.H.A.R.E. are tax exempt in the United States.

S.H.A.R.E. has been recently renamed the Skeptics and Humanist Aid and Relief Effort and has now become a program of the wider-reaching Center for Inquiry, responding to the need to continue providing an alternative for those who wish to contribute to charitable efforts without the intermediary of a religious organization in this time of great need.

Of note is the fact that 100% of any donations are slated to go directly to where they’re needed most, with no administrative or other costs deducted, and as noted above, this is a secular organisation.

Doctors Without Borders/Médecins Sans Frontières (MSF)

USGS Report

See also: Recent sources on Haitian culture and social change @ anthropologyworks

This list is intended to provide a guide to recent resources on culture and society in Haiti for people who wish to be better informed themselves about the context in which the recent earthquake and its devastation are occurring. With apologies, most of the journal articles are not public access.

Furthermore, we really encourage everyone to visit InterAction’s Haiti response page, which includes a variety of ways to help out.

image from mashable.com

Here’s the abstract of some news which John Hawks describes as “really, really weird”:

The human Y chromosome began to evolve from an autosome hundreds of millions of years ago, acquiring a sex-determining function and undergoing a series of inversions that suppressed crossing over with the X chromosome1, 2. Little is known about the recent evolution of the Y chromosome because only the human Y chromosome has been fully sequenced. Prevailing theories hold that Y chromosomes evolve by gene loss, the pace of which slows over time, eventually leading to a paucity of genes, and stasis3, 4. These theories have been buttressed by partial sequence data from newly emergent plant and animal Y chromosomes5, 6, 7, 8, but they have not been tested in older, highly evolved Y chromosomes such as that of humans.

Here we finished sequencing of the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY. By comparing the MSYs of the two species we show that they differ radically in sequence structure and gene content, indicating rapid evolution during the past 6 million years. The chimpanzee MSY contains twice as many massive palindromes as the human MSY, yet it has lost large fractions of the MSY protein-coding genes and gene families present in the last common ancestor.

We suggest that the extraordinary divergence of the chimpanzee and human MSYs was driven by four synergistic factors: the prominent role of the MSY in sperm production, ‘genetic hitchhiking’ effects in the absence of meiotic crossing over, frequent ectopic recombination within the MSY, and species differences in mating behaviour. Although genetic decay may be the principal dynamic in the evolution of newly emergent Y chromosomes, wholesale renovation is the paramount theme in the continuing evolution of chimpanzee, human and perhaps other older MSYs.

The rest of the content is behind Nature’s paywall, but Hawks offers some additional comment regarding the rest of the paper, specifically three options that might account for the unexpected gulf of difference, described within the paper thus:

Indeed, at 6 million years of separation, the difference in MSY gene content in chimpanzee and human is more comparable to the difference in autosomal gene content in chicken and human, at 310 million years of separation.

Option 1: Maybe nothing, Option 2: Massive changes in gene regulation, and Option 3: Hitchhiking, all of which is which is prefaced by this:

The Y chromosome was part of the initial chimpanzee genome draft, and was recognized then as a “clear outlier” in showing low human-chimpanzee sequence similarity (Chimpanzee Genome Consortium 2005). But it wasn’t obvious just how different it was because the relatively short sequencing reads aligned fairly well with the human draft. That comparison also seems not to have included the missing genes (they might have just been missed during sequencing), or duplications. Moreover, the Y chromosome includes a high fraction of repetitive sequence, including long front-to-back, or “palindromic” passages.

Only with very long reads with long overlaps is it possible to straighten out the large-scale sequence, and thereby detect sequence reorganizations and large copy number variants. This kind of intensive sequencing has so far been completed only for chromosome 21 and now the Y chromosome.

To read the rest of his commentary, just head over to Hawks’ Weblog.

Reference:

Hughes JF and 16 others. 2010. Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content. Nature (early online) doi:10.1038/nature08700

Previously on 4SH…

The Avatar Edition, aka number 83, was published by Eric Michael Johnson, on December 30, 2009, at 8:00 AM. Although I’ve thus far omitted to post something on this edition, I’ll add a brief word here. The first few posts deal with James Cameron’s latest project to hit the cinemas in the guise of Avatar which by all accounts has come in for a pretty mixed reception; I haven’t seen it yet, so I can’t offer any insights, but the related posts at 4SH look behind the scenes at some of those who became involved in the film’s creation, which even had a language specifically created for it.

In addition there were a number of other intriguing posts, dealing with more linguistics, archaeology, biological evolution and Applied/Theoretical anthropology, including a post from the excellent Anthropology in Practice blog, which concentrates more on  life in the modern day – although I spend probably too much time patrolling the palaeoanthropology beat, it’s always interesting to read thoughts and observations of anthropologists as they navigate their way through and across the conurbations, in this particular case the New York of today. In any case, be sure to check each and every post of this edition, as you never know what you didn’t know until you suddenly discovered etc etc…

On now to zinjanthropus  at A Primate of Modern Aspect, episode 84, where the following takes place between x AM and y PM:

In this Gratuitous Gelada Edition, as we might expect from the title and host, a number of posts feature our primate relatives – as observation-based research produces ever-growing cascades of data from cultural and behavioural studies, so our close relatives become ever more interesting. As the extent to which our own evolution is entangled with non-human counterparts appears to be more detailed and tightly bound than could have been imagined in previous decades, many notions such as enhanced cognitive abilities through increased brain size amongst H. sapiens sapiens to explain our ‘superiority’ are fast becoming myth, especially when considering how we supposedly came to be uniquely culture-adapted modern humans. Moreover, it is becoming increasingly clear that behaviours such as tool-use are much more widespread across the animal kingdom, as this recent article on stingrays indicates.

Another notable aspect of this edition of Four Stone Hearth is the re-appearance of Julien Riel-Salvatore at A Very Remote Period Indeed – one of the best bloggers out there on palaeoanthropology, and I thoroughly recommend anyone who has not already done so to bookmark the site/ subscribe to the feed, or otherwise initiate your preferred method of keeping abreast of new posts.

In fact, the very next edition of Four Stone Hearth is due to be hosted by Julien on January 27th, so just check the 4SH site for details of how to submit material, as well as further information on how to host your very own action-packed and cliff-hanging edition.

Science Daily report on recent and ground-breaking research announced in a letter to Nature Genetics by Drs. John D. Reveille and Matthew A. Brown et al that has identified two genes that are now believed to play a significant role in ankylosing spondylitis. AS is an inflammatory condition of the spine and joints, one that over the past 35 years has become extremely familiar to this blogger. Thus far, only the abstract of the authors’ letter to Nature is freely accessible, and it reads thus:

To identify susceptibility loci for ankylosing spondylitis, we undertook a genome-wide association study in 2,053 unrelated ankylosing spondylitis cases among people of European descent and 5,140 ethnically matched controls, with replication in an independent cohort of 898 ankylosing spondylitis cases and 1,518 controls.

Cases were genotyped with Illumina HumHap370 genotyping chips. In addition to strong association with the major histocompatibility complex (MHC; P < 10−800), we found association with SNPs in two gene deserts at 2p15 (rs10865331; combined P = 1.9 × 10−19) and 21q22 (rs2242944; P = 8.3 × 10−20), as well as in the genes ANTXR2 (rs4333130; P = 9.3 × 10−8) and IL1R2 (rs2310173; P = 4.8 × 10−7).

We also replicated previously reported associations at IL23R (rs11209026; P = 9.1 × 10−14) and ERAP1 (rs27434; P = 5.3 × 10−12). This study reports four genetic loci associated with ankylosing spondylitis risk and identifies a major role for the interleukin (IL)-23 and IL-1 cytokine pathways in disease susceptibility.

I’m not sure to what degree this technical data will be comprehensible to the lay AS patient, (and the revelation so by way of clarification, I’ll refer back to the Science Daily article, from which the following is excerpted:

The findings, a critical milestone in the understanding of AS, are published in the January issue of Nature Genetics, a journal that emphasizes research on the genetic basis for common and complex diseases. “This helps us better understand what is driving this disease and gives us direction for new treatments and diagnostic tests,” said John D. Reveille, M.D., the study’s principal investigator and professor and director of the Division of Rheumatology and Clinical Immunogenetics at The University of Texas Medical School at Houston.

Reveille, the university’s Linda and Ronny Finger Foundation Distinguished Chair in Neuroimmunologic Disorders, and Matthew A. Brown, M.D., professor of immunogenetics at Australia’s University of Queensland, led the research by the Triple “A” Spondylitis Consortium Genetic Study (i.e. the TASC or Australo-Anglo-American Spondylitis Consortium). Based on work from a genome-wide association scan, the team identified genes ANTXR2 and IL1R2 as well as two gene deserts, segments of DNA between genes on chromosomes 2 and 21 that are associated with ankylosing spondylitis. Importantly, the study also confirmed the Triple “A” Australo-Anglo-American Spondylitis Consortium’s previously reported associations of genes IL23R and ERAP1, formerly known as ARTS1.

The research doesn’t detail exactly what new treatments might one day become available, but there is comfort to be derived from the fact that research such as this will in the short term enable rheumatologists to more quickly identify AS in patients, thus affording those patients the opportunity of obtaining suitable anti-inflammatory medications sooner rather than later. This addresses a problem that has affected many, in that AS isn’t always easy to diagnose in its primary stages or at onset, with the consequence that there can often be a delay of several years  in prescribing effective medicines, although we’ve come a long way since the days when AS patients were routinely encased in plaster for weeks on end in a misguided bid to limit mobility and ease the pain.

For the more technically adept patient, there is another paper, freely accessible and published in 2001 at PubMed, namely Whole-Genome Screening in Ankylosing Spondylitis: Evidence of Non-MHC Genetic-Susceptibility Loci, for which this is the abstract:

Ankylosing spondylitis (AS) is a common inflammatory arthritis predominantly affecting the axial skeleton. Susceptibility to the disease is thought to be oligogenic. To identify the genes involved, we have performed a genomewide scan in 185 families containing 255 affected sibling pairs. Two-point and multipoint nonparametric linkage analysis was performed. Regions were identified showing “suggestive” or stronger linkage with the disease on chromosomes 1p, 2q, 6p, 9q, 10q, 16q, and 19q. The MHC locus was identified as encoding the greatest component of susceptibility, with an overall LOD score of 15.6. The strongest non-MHC linkage lies on chromosome 16q (overall LOD score 4.7). These results strongly support the presence of non-MHC genetic-susceptibility factors in AS and point to their likely locations.

Here’s a final word from Science Daily, referring to the first paper mentioned above:

Laurie Savage, co-principal investigator and executive director of the Spondylitis Association of America (SAA) said, “These new breakthroughs are, indeed, good news for those whom we serve. It is very encouraging to know that the health impact and economic consequences of spondyloarthritis in the world eventually will be contained as a direct consequence of the dedication of Drs. Reveille, Brown and colleagues, and that of the many individuals affected by spondyloarthritis who have participated in these studies.”

The study was supported in part by two grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Other study contributors from the UT Health Science Center at Houston are research associates Laura Diekman and Rui Jin and Xiaodong Zhou, M.D., associate professor of medicine.

If the aspirations of the researchers are indeed realised, there are sure to be many thousands of suitably relieved people in the future, who will doubtless be most grateful for the efforts made by the teams and their volunteers.

Anthrax toxin receptor 2 (ANTXR2)

Interleukin 1 receptor, type II (IL1R2)

image from Ankylosing Spondylitis Association of Ireland

References:

Genome-wide association study of ankylosing spondylitis identifies non-MHC susceptibility loci by John Reveille and Matthew Brown et al, Nature Genetics Published online: 10 January 2010 | doi:10.1038/ng.513

Whole-Genome Screening in Ankylosing Spondylitis: Evidence of Non-MHC Genetic-Susceptibility Loci by S. H. Laval, A. Timms, S. Edwards, L. Bradbury, S. Brophy, A. Milicic, L. Rubin, K. A. Siminovitch, D. E. Weeks, A. Calin, B. P. Wordsworth and M. A. Brown, Am J Hum Genet. 2001 April; 68(4): 918–926. Published online 2001 February 27

In keeping with these wintry conditions, there’s a veritable avalanche of news concerning the late lamented Neanderthals this past week, including spears, teeth and decorated marine shells, with much of  the debate concentrating, as ever, on the physical and behavioural differences between the Neanderthal archaic humans and the subsequent anatomically modern humans (AMH) with whom they were obliged to share residence and resources in Upper Palaeolithic Eurasia, especially in western Europe .

As ever, some of the research seeks to persuade us of putative differences between the two species, and some argues that Neanderthals were greatly more cognitively advanced than traditionalists would have us believe.

I’m going to continue with this post, in which I’ll discuss the research of Steven E. Churchill, Associate Professor in Evolutionary Biology at Duke University, Durham NC, who has conducted research into the evolution of projectile weaponry, which he contends was invented by AMH. and moreover gave them an enhanced ability to hunt animals at a greater distance, thus giving them a killer advantage over Neanderthals, who apparently were only able to deploy thrusting spears, forcing them to hunt prey at much closer quarters. Slightly more controversially he claims that projectile weapons allowed for a modicum of social control in early societies, and today allows for control of modern societies and as a means for resolving – or exacerbating – disputes between nation states or other warring parties such as religious groups, i.e. through the use of guns, shells and bullets, which themselves are the descendants of the spears, darts and arrows of yesteryear.

These recent studies are covered amongst others by CBS News and American Scientist, who as noted at Mind Hacks, have produced a great 45-minute podcast, in which Professor Churchill holds forth in a lecture, which reprises a paper published in the Journal of Human Evolution in July 2009. He opines that before the AMH invention of projectile weapons, ancient humans were to a great extent confined to hunting large mammals, whom they sought to take by surprise or ambush, and finishing them off by stabbing them to death.

In contrast, we are asked to accept that with the invention of projectile weaponry, such as throwing-spears, spear throwers and the bow and arrow, AMH were able to expand the range at which they hunted prey, from around an average of 4 metres for thrusting spears to around 20- 40 metres with projectiles or missiles, which in turn would have given them much better opportunities to kill more prey on a more frequent basis, ultimately leading them to out-compete the Neanderthals into extinction.

Although he doesn’t completely rule out the idea that Neanderthals or pre-Mousterian humans never threw spears, he discounts the Schöningen spears‘ (+image) mooted comparison with modern-day javelins, and notes the Mousterian stone points bear evidence of having been hafted onto wooden shafts for use as thrusting weapons. Staying with the archaeological evidence, he cites Upper Palaeolithic spear- throwers, complete with their elegant engravings, as a strong indication that AMH had developed fully functional projectile weapons systems, and further surmises that the physical attributes of AMH, especially in the upper limb-bones, was much more conducive to throwing spears than those of Neanderthals.

Which is all well and good, but by concentrating solely on artefactual archaeology, in the guise of stone points and spear shafts, I think Professor Churchill has missed out on other evidence that strongly suggests that Neanderthals and even earlier archaic humans emphatically did not rely only on killing large mammals by spearing them to death as their only means of hunting meat – the zooarchaeological evidence from Ruth Blasco et al at Bolomor Cave and Naama Goren-Inbar et al at Gesher Benot Ya’akov paints a subtly different picture, because from those sites we have the evidence in the remains of small mammals such as rabbits at 350 kya, birds, possibly ducks or geese, dating to 150 kya,and fish such as carp at 780 kya.

In fact, by taking in this other documented and peer-reviewed evidence, we see a much more interesting story emerging, because although as yet there is no evidence at all to show how these elusive food resources were obtained, it seems reasonable to assume that brain rather than brawn in archaic humans was the key element in their acquisition. Whether the use of bait or traps was known, or (however seemingly improbable) even that other animals (such as hunting birds, ferrets or dogs) were somehow partially domesticated, trained or otherwise induced to target, pursue and capture some of these prey at the humans’  behest, I think it’s necessary to stand back and consider at the larger picture of meat acquisition skills among archaic humans that is slowly unfolding

However the idea that Neanderthals weren’t the top predators in the food-chain during their Middle Palaeolithic sojourn might well be true – they merely needed to be an adequate predator in competition with the other carnivores, though whether this competition by default restricted Neanderthal population numbers, keeping them in an equilibrium of  sorts with the Palaleo-fauna is an idea that hopefully will be examined further, although conclusive proof might be hard to come by.

And whereas the tortoises at Bolomor wouldn’t have required too much effort to catch, nor the mussels and (presumably scavenged dolphin) at Gorham’s Cave, from c.24,5 kya, it should also be borne in mind that archaic humans didn’t just rely on the faunal population for all their food. There are fish and plant remains from the cave at El Salt, another Neanderthal occupation site in modern-day Spain, and it’s possible that future evidence gleaned from phytoliths on ancient stone tools will yield further evidence that humans were eating cereals and grains a great deal earlier than for example the onset of agriculture, as hinted at by this recent article on sorghum consumption, at 100 kya, albeit in this case, by AMH.

Having said that, it’s worth bearing in mind that to maintain their more robust bodies, Neanderthals in particular required a vast calorific daily intake to sustain themselves, and thus it is no surprise to find that many of their food remains are indeed from those of large mammals, especially at inland sites – but where other food items were available, it’s clear that they and their predecessors were readily able to adapt to marine and lacustrine environments as well. However, I wonder if they dined exclusively on the fare on offer for more than a few days here and there,  as ongoing pangs of hunger urged them to supplement their diet with those larger mammals.

So although I’d agree in principle that projectile weapons systems do indeed indicate that AMH adopted new technologies and behaviours as a direct result, I think it’s hard to make the case that archaic humans became extinct because such weapons were absent from their itinerary – unless of course, we consider the use of such weapons in the context of fighting between the AMH and Neanderthals, or ‘competitive exclusion’ at kill-sites or over larger areas of favoured territories.

Professor Churchill relates how in recent years there have been more precise studies of carnivores, to the extent that a behaviour identified as ‘interference exclusion’ has been identified, whereby one carnivore species steals a carcass from another, and other circumstances whereby one species will kill competing carnivore species. Mention is made not only of the way in which adults will kill subordinate species, but that carnivore species in general will kill the young of their competitors – he cites lions as killing hyena pups, and wild dogs as killing lion cubs, not because they are part of their normal diet, but because they pose a threat to their own survival.

This is then extrapolated to an example whereby the Professor believes that lions eating a carcass would not have been unduly alarmed by the approach of 3 or 4 Neanderthals approaching with thrusting spears, but that once AMH arrived in greater numbers and armed with projectile weapons, the advantage would have been with the humans. He also notes that in the millennia leading up to and following on from around 30 kya, many species including sabre-toothed cats and cave bears amongst many others became extinct, though whether they were deliberately killed off by spear-throwing humans, in scenes that presaged the Terminal Pleistocene extinction event in the New World around 13 kya, is still an open question. And of course the extinction events in Australia at 40kya, and the less noted African Late Pleistocene extinctions could presumably be included as candidates for consideration in the light of projectiles being hurled with intent around their landscapes too.

The question raised by the carnivore studies is whether AMH humans acted in the same way as their carnivorous counterparts, and set about excluding the Neanderthals by any means possible. But the fact the AMH and Neanderthals were almost certainly able to verbally communicate with one another makes the situation different, regardless of whether one had better hunting technology than the other, and it seems reasonable to assume that a variety of exchanges, ranging from friendly to hostile, took place over a period lasting around 20,000 years, in the European context at least.

The CBS article mentioned above takes us slightly farther afield, specifically to Shanidar Cave, in modern-day Iraq, where a healed wound in the individual known to us now as Shanidar III has been the subject of further study by Professor Churchill, as he addresses the intriguing mystery of how this person came to be injured by a spear-point a couple of years before he died. Here’s a snippet from the article:

Churchill’s curiosity about the fate of Shanidar 3 led him to try re-creating the sharp, deep scratch in the left ninth rib of this hapless Neanderthal. This strategy actually came from Churchill’s colleague John Shea, a paleoanthropologist at Stony Brook University in New York who reconstructs the behavior of prehistoric peoples by analyzing their stone tools. To understand how stone points are worn down when piercing flesh and bone, Shea had run a set of experiments, stabbing goat carcasses and then noting the damage to the tools.  Churchill hoped to compare the cuts on Shea’s goat bones to the mark on Shanidar 3′s rib.

Unfortunately, the goat bones were so damaged by the blows that “it was impossible to analyze them,” he says.  He concluded that he would have to do his own experiments to replicate the physics of Shanidar III’s prehistoric wound. Neanderthals were the power-thrusters of the Paleolithic world, driving their heavy spears with great kinetic energy and momentum into bison, boar, and deer. If Shanidar 3 had been injured by such a thrust, it would suggest that he had gotten into a fight with another Neanderthal, or perhaps that he had been hurt in a hunting accident. But if the wound had resulted from a lighter spear-from a projectile deftly thrown at a distance, with less momentum and energy-the attacker was most likely human. There is no evidence whatsoever that Neanderthals ever used throwing spears, Churchill says.

After inflicting a set of sample wounds on pig bones, which are close in terms of size and shape to those of Neanderthals (and which were easily obtained from a nearby slaughterhouse), Churchill and his team of students spent an evening cleaning the bones by boiling them in hot water and Biz, a laundry detergent containing enzymes that are, Churchill says, “really good at breaking down proteins.” The process revealed signs of damage to the pig bones similar to those seen in Shanidar 3. “We cannot definitively rule out accidental wounding, attack with a knife, or attack with a hand-delivered, heavy Neanderthal spear,” Churchill says. “But Shanidar 3′s wound is most consistent with injury from a lightweight, long-range projectile weapon.”

As we see from this earlier post by Kambiz here at Anthropology.net, back in 2008, regardless of whether his rib injury was deliberate or accidental, Shanidar III is a pretty interesting individual in his own right, because dental analysis indicates that plants might conceivably have constituted part of his diet, further underlining the idea that Neanderthals weren’t exclusively reliant upon big game animals at every meal-time – however, the authors of that study are cautious in making a definite statement to that effect.

The fact that he had a painful condition, osteoarthritis in one foot, further enhances the mystery as to how he came by his rib wound – if as Churchill suggests,  involved in a skirmish with AMH, why was he considered a threat to the extent that one of their number deemed it necessary to launch a projectile at him, especially given his limited mobility? Further, having been wounded, why was he not finished off on the spot – speedy flight from the scene of an ugly encounter would have been difficult, and yet he managed to survive the incident and live on for a few painful years thereafter.

Projekt Schöninger Speere

Schöningen – ein Projekt der archäologischen Denkmalpflege

image of Shanidar III rib 9 from El extraño caso del neandertal asesinado – Terrae Antiqvae

References:

1. Shanidar 3 Neandertal Rib Puncture Wound and Paleolithic Weaponry by Steven E. Churchill,  Robert G. Franciscus, Hilary A. McKean-Peraza, Julie A. Daniel and Brittany R. Warren Journal of Human Evolution Volume 57, Issue 2, August 2009, Pages 163-178 doi:10.1016/j.jhevol.2009.05.010

2. Procesado y consumo antrópico de conejo en la Cova del Bolomor (Tavernes de la Valldigna, Valencia). El nivel XVIIc (ca 350 ka), Blasco et al

Dental maturational sequence and dental tissue proportions in the early Upper Paleolithic child from Abrigo do Lagar Velho, Portugal — PNAS

This is a paper in which the authors investigate the dentition of the Abrigo do Lagar Velho child, excavated from a rock-shelter in Portugal, back in November 1998 by Cidália Duarte and João Zilhão, later assisted by Professor Erik Trinkaus. The unusually robust cranial and post-cranial features prompted the researchers to suggest that this specimen, LV1, was a hybrid of Neanderthal and AMH ancestry, a theory which has since come under intense attack from subsequent genetic researchers who contend there is almost no evidence in our modern genome of Neanderthal admixture, especially where mtDNA sequences have been investigated. This in turn has been countered by the argument that it is hardly surprising we see so little evidence tens of millennia later, as the Neanderthal influence could by now simply not have survived intact down through so many generations of humans, due to those direct descendants of limited interbreeding dying out along the way at the expense of AMH – more of which later.

The paper by Priscilla Bayle et al opens with this abstract…

Neandertals differ from recent and terminal Pleistocene human populations in their patterns of dental development, endostructural (internal structure) organization, and relative tissue proportions. Although significant changes in craniofacial and postcranial morphology have been found between the Middle Paleolithic and earlier Upper Paleolithic modern humans of western Eurasia and the terminal Pleistocene and Holocene inhabitants of the same region, most studies of dental maturation and structural morphology have compared Neandertals only to later Holocene humans.

To assess whether earlier modern humans contrasted with later modern populations and possibly approached the Neandertal pattern, we used high-resolution microtomography to analyze the remarkably complete mixed dentition of the early Upper Paleolithic (Gravettian) child from Abrigo do Lagar Velho, Portugal, and compared it to a Neandertal sample, the late Upper Paleolithic (Magdalenian) child of La Madeleine, anda worldwide extanthumansample.Someaspects of the dental maturational pattern and tooth endostructural organization of Lagar Velho 1 are absent from extant populations and the Magdalenian specimen and are currently documented only among Neandertals.

Therefore, a simple Neandertal versus modern human dichotomy is inadequate to accommodate the morphostructural and developmental variation represented by Middle Paleolithic and earlier Upper Paleolithic populations. These data reinforce the complex nature of Neandertal-modern human similarities and differences, and document ongoing human evolution after the global establishment of modern human morphology.

…and continues with this from the introduction:

It was with the goal of assessing whether the dental developmental patterns and microstructure of these earlier modern humans contrasted with later modern humans, and possibly approached the condition seen in the Neandertals, that we anaanalyzed the remarkably complete dentition of the Lagar Velho 1 child (19). Discovered in Portugal in 1998, this fossil is the &gt;90% complete skeleton of a child (4–5 years old on the basis of dental maturation and limb bone lengths) ritually buried in a recess in the back wall of a rock shelter, at the base of an ∼3-m thick Gravettian to Solutrean stratigraphic sequence. The 14C-dated components of the burial context concur in placing the burial ∼24.5 ka 14C BP (∼30,000 calendar years ago), some five millennia after the replacement/assimilation of the last Neandertal populations of Iberia (20, 21). Preserving 46 of the possible 48 teeth (from calcified germs to complete teeth), all except one upper P4 and one lower P4 (and the four yet-to-calcify M3s) (19), the Lagar Velho 1 dentition provides a unique opportunity to assess these odontological aspects.

The Gravettian/Solutrean boundary obviously occurred sometime between the start of the Gravettian c.28 kya and the start of the Solutrean, c.21 kya,and it’s interesting to note that the 4-5 year old child appears to have been given what is described as a ritual burial, presumably around 24/25kya, some 20,000 years after the earliest recorded evidence of AMH in Europe.

This would make it a contemporary of the Gorham’s Cave Neanderthals at Gibraltar, but older than those whose remains have been proposed as even later surviving Neanderthals at La Carihuela, as well as another even younger site at Esquilleu that has yet to be confirmed in north of Spain, in both of which instances, Neanderthals appear to have not mixed with the AMH population, but survived living the Neanderthal life along with their traditional Mousterian stone tools

Those three sites tell their own story – La Carihuela holds the promise of actual Neanderthal fossils, tentatively dated to 21.5 kya, whilst Gorham’s Cave at 24,5 kya and Esquilleu, maybe a similar age as La Carihuela, contain Mousterian stone tools, and coming right at the end of the known existence of the Neanderthals, appear strongly suggestive of a Neanderthal population that was far from fully integrated into that of the AMH, either by blood or technology, thus making the putative hybrid from Portugal an exception to the general rule.

Here’s a note regarding the complex results of the research:

With the exception again of the Ui1 limited to the relative enamel thickness, both the average (AET) and relative (RET) enamel thickness values (Methods) recorded for all of Lagar Vehlo 1’s teeth follow the EH estimates, systematically setting it apart from the Neandertals because of their lower values (Figs. S2 and S3). In this respect, notably for the two deciduous and permanent molars, the extant human-like pattern of enamel distribution displayed by this child’s dentition is also evinced by the comparative thickness cartographies (Fig. S4).

For all of the absolute and relative variables describing dental tissue proportions, except the EDJ surface area, the results shown by the Lagar Velho 1’s lower first permanent molar (LM1) conform to those from its deciduous Lc and Lm2; they closely resemble the extant human figures. In all three cases, the potential influence of dental wear is negligible or null (Table S5). It is noteworthy that the lower canine of Lagar Velho 1 is affected by localized enamel hypoplasia (29) (Fig. 1C and Fig. S1C). Accordingly, the values displayed by both Upper Paleolithic children for the percent of the crown volume that is dentine and pulp and for the relative enamel thickness (Table S3) should be further shifted closer to the extant human values.

As a point of interest, this paper follows on from another, Anterior Tooth Growth Periods in Neandertals Were Comparable to those of Modern Humans, for which this is the abstract, and the rest of the paper is freely accessible too.

Summarised by Alan Boyle at Cosmic Log, we see:

Researchers led by Priscilla Bayle of France’s Museum of Natural History used X-ray micro-tomography to create 3-D images of the child’s teeth. They found that the front teeth were delayed in their degree of formation, compared with the state of the teeth farther back on the jaw. The front teeth also had more dentin and pulp than the teeth of more recent humans, but less enamel.  These characteristics don’t fit the pattern seen in today’s human population, or even the pattern for 12,000-year-old human teeth. They come closer to fitting the pattern for Neanderthals, the researchers said.

The University of Bristol’s João Zilhão, who found the skeleton and is a co-author of the study, said in a news release that the tooth analysis joins a growing body of evidence “that shows these ‘early modern humans’ were ‘modern’ without being ‘fully modern.’”  The university said the report “raises controversial questions about how extensively Neanderthals and modern human groups of African descent interbred when they came into contact in Europe.”

However, the study itself stops short of directly addressing those questions. Instead, the researchers say their findings “reinforce the complex nature of Neanderthal-modern human similarities and differences, and document ongoing human evolution” even after the rise of modern humans. They suggest further studies of juvenile teeth, going back 100,000 to 200,000 years, could make a significant contribution to charting the human family tree.

Although the authors decline to declare that this represents clear evidence of AMH and Neanderthal interbreeding, it’s difficult to ascribe a meaningful alterntative, especially when we consider the post-cranial elements of the specimen, whose limb proportions conform more closely to the Neanderthal model. Although some researchers have tried to pass this off as being evidence for nothing more than a ‘chunky kid’, a holistic approach which takes in discrete elements from both cranial and post-cranial morphology, in my opinion conclusively points us in the direction of AMH and Neanderthal admixture.

Such consideration of the skeletal remains as a whole certainly helped clarify the debate surrounding H. floresiensis, aka the Hobbit from Flores, where debates which only considered the cranial features persuaded some that the specimen was a diseased modern. Reality, however begged to differ, and since the publication of detailed research, especially on the out-sized feet and peculiar wrists of the hobbit, it seems abundantly clear that whoever else she may have been, LB1 was no anatomically modern human.

In the case of the Lagar Velho child, I think the most interesting results to come will be when its entire genome has decoded, if and when that ever happens – whether that tells us conclusively if this was indeed a hybrid child remains to be seen, but assuming that research of this type is carried out, we should at least have several more details of the overall picture.

Although this paper is freely accessible, you might find it easier to find it in this comment by Martin Cagliani, author of  Mundo Neandertal, who has very kindly provided it – hat tip to Maju/Luis for the heads-up to that. A link for the supplementary material appears below, and is also well worth checking out.

Bristol University Press Release

Fate of the Neandertals – João Zilhão, Archaeology.org, July/August 2000

Learning to Love Neanderthals – Robert Kunzig, Discover Magazine, August 1999

References:

1.Dental maturational sequence and dental tissue proportions in the early Upper Paleolithic child from Abrigo do Lagar Velho, Portugal — PNAS by Priscilla Bayle, Roberto Macchiarelli, Erik Trinkaus, Cidália Duarte, Arnaud Mazurier and João Zilhão

Published online before print January 4, 2010, doi: 10.1073/pnas.0914202107

2.Download Supporting Information (PDF)

3. Anterior Tooth Growth Periods in Neandertals Were Comparable to those of Modern Humans – by Debbie Guatelli-Steinberg,*†‡ Donald J. Reid, Thomas A. Bishop, and Clark Spencer Larsen

Proc Natl Acad Sci U S A. 2005 October 4; 102(40): 14197–14202. Published online 2005 September 23. doi: 10.1073/pnas.0503108102.

4. No Evidence of Neandertal mtDNA Contribution to Early Modern Humans – Serre D, Langaney A, Chech M, Teschler-Nicola M, Paunovic M, et al. (2004) No Evidence of Neandertal mtDNA Contribution to Early Modern Humans. PLoS Biol 2(3): e57. doi:10.1371/journal.pbio.0020057

Can crows keep the score in a game, is a football a type of tool, and should we pay attention to what someone says on the questionable basis that they are older – and thus wiser – than ourselves? None of those questions are addressed in this post, but nevertheless, there are a few things worth reading online today, of which the following are but three examples.

First up, the Royal Society has a couple of interesting papers for our perusal, both of which are freely accessible, to wit:

Tool Use by Wild New Caledonian Crows Corvus moneduloides at Natural Foraging Sites, for which this is the abstract:

New Caledonian crows Corvus moneduloides use tools made from sticks or leaf stems to ‘fish’ woodboring beetle larvae from their burrows in decaying wood. Previous research on this behaviour has been confined to baited sites, leaving its ecological context and significance virtually unexplored. To obtain detailed observations of natural, undisturbed tool use, we deployed motion-triggered video cameras at seven larva-fishing sites. From 1797 camera hours of surveillance over 111 days, we recorded 317 site visits by at least 14 individual crows. Tool use was observed during 150 site visits. Our video footage revealed notable variation in foraging success among identifiable crows.

Two nutritionally independent, immature crows spent considerable time using tools, but were much less successful than local adults, highlighting the potential role of individual and social learning in the acquisition of tool-use proficiency. During systematic surveys of larva-fishing sites, we collected 193 tools that crows had left inserted in larva burrows. Comparing these tools with the holes in which they were found, and with raw materials available around logs, provides evidence for tool selectivity by New Caledonian crows under natural conditions. Taken together, these two complementary lines of investigation provide, to our knowledge, the first quantitative description of larva fishing by wild crows in its full ecological context.

Whilst back in the world of primates, we have this:

Attention to Elders’ Voice in Non-human Primates – here’s the abstract:

The observed respect and attention to elders’ speech in traditional cultures appears to have a ‘universal’ component which questions its possible biological bases. Animals present differential attention to the vocalizations of other individuals according to their characteristics but little is known about the potential propensity to pay more attention to vocalizations of elders. On the basis of several hundreds of vocal exchanges recorded, here we show that aged female Campbell’s monkeys (Cercopithecus campbelli), despite being significantly less ‘loquacious’ than their younger adult counterparts, elicit many more responses when calling. These findings show that attention to elders’ vocal production appears in non-human primates, leading to new lines of questioning on human culture and language evolution.

All of which is followed by:

Why England’s Soccer Team Keeps Losing on Penalty Shots

With all this talk of tool use, paying heed to elders and social learning amongst non-humans, it is becoming increasingly difficult to ascribe much in the way of definitive activities that properly explain why we humans are so different from all other members of the animal kingdom. However, playing football (aka ‘soccer’ to USAsians) is one activity for which our bipedality alone makes us uniquely adapted, and in common with most other sports, psychology can play just as important a role as technique, especially when it comes to taking the dreaded penalty kick.

As many a long-suffering England fan will attest, the national team have a depressing tendency to getting themselves eliminated from major competitions in penalty shoot-outs, whilst teams like Germany appear to prosper greatly from such sudden-death events, for reasons that have never been satisfactorily explained by scientists – or anyone else, for that matter.

About a month ago, in early December 2009, Chelsea midfielder Frank Lampard missed a penalty in his side’s 2-1 defeat away to Manchester City,  prompting a comment that being the consummate professional he is, ‘Lamps’ was getting in some early practise at missing penalties for England in the upcoming July, 2010 World Cup – although in fairness to the player, he subsequently scored an equalising spot-kick at Upton Park two weeks later, as his team came back from a goal down to draw 1-1 with West Ham. To his further credit, the ref had ordered the kick to be re-taken twice, with Lampard beating the ‘keeper on each occasion, after which the Chelsea fans amused themselves by chanting ’3-1, 3-1′ long into the night, presumably in the hope of subliminally persuading the ref to chalk up two extra goals on their account.

A new paper reported in Science Daily may be of help to Lampard and other England players this coming summer in South Africa, as it offers some advice to would-be scorers of penalty kicks, placing the emphasis on ignoring the opposing goal-keeper, and concentrating instead on placing the ball just inside either post, making the shot harder to save. The idea is that anxious players tend to look too long at the ‘keeper before the penalty is taken, which we are told results in many kicks being overly centralised, and thus much easier to save. As we see from the abstract:

The current study sought to test the predictions of attentional control theory (ACT) in a sporting environment. Fourteen experienced footballers took penalty kicks under low- and high-threat counterbalanced conditions while wearing a gaze registration system. Fixations to target locations (goalkeeper and goal area) were determined using frame-by-frame analysis. When anxious, footballers made faster first fixations and fixated for significantly longer toward the goalkeeper. This disruption in gaze behavior brought about significant reductions in shooting accuracy, with shots becoming significantly centralized and within the goalkeeper’s reach. These findings support the predictions of ACT, as anxious participants were more likely to focus on the “threatening” goalkeeper, owing to an increased influence of the stimulus-driven attentional control system.

I’m not sure how far back, or in which specific ways this might apply to early human evolution – ignoring one’s opponent – or at least not looking directly into their eyes – is often a sign during a heated argument that fisticuffs are about to ensue, possibly a sub-conscious ruse to lull the opposition into a false sense of security, or allowing the assailant to think through the moves without being distracted or coming under the thrall of their target by focussing overt attention on them. However, it isn’t clear whether this is a socially mediated skill or an instinctive behaviour that kicks in at the flick of a neuronal switch.

Returning to the Royal Society, BBC Radio 4 are running a mini-series of its 350-year history, this week, with ‘In Our Time’ presenter Melvyn Bragg, well-known wit and raconteur. To get the previous programmes aired this week, it might be necessary to subscribe to the podcast via iTunes.

image from here

References:

Tool Use by Wild New Caledonian Crows Corvus moneduloides at Natural Foraging Sites – by  Lucas A. Bluff, Jolyon Troscianko, Alex A. S. Weir, Alex Kacelnik and Christian Rutz

Published online before print January 6, 2010, doi: 10.1098/rspb.2009.1953

Attention to Elders’ Voice in Non-human Primates – by Alban Lemasson, Enora Gandon  and Martine Hausberger

Published online before print January 6, 2010, doi: 10.1098/rsbl.2009.0875

Anxiety, Attentional Control, and Performance Impairment in Penalty Kicks – by Mark R. Wilson, Greg Wood, Samuel J. Vine

Journal of Sport and Exercise Psychology JSEP, 31(6), December 2009, Copyright © 2009