Anthropology.net

If you don’t follow or subscribe to our sister blog Primatology.net, I want to make you aware of an anthropological post I just put up on the newly published orangutan genome. Click here to read about some of the findings, but to wet your appetite, it involves the estimated divergence of the two orangutan species at 400,000 years ago, the relative stabilitiy of their genomes compared to human and chimpanzee, and lastly the shared similarities between human and orang, and not orang and chimp.

Sumatran Orangutan (Pongo abelii)

For quick access to the primary sources, the full citations to the papers discussed are below this read more link.

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Inspired by the Dodecad Ancestry Project by Dienekes Pontikos and Eurogenes Ancestry Project by David Wesolowski, Zack Ajmal (with the help of Razib Khan) has started the Harappa Ancestry Project. Zack explains the motivation behind this project,

“It is a project to analyze (autosomal) genetic data of participants of South Asian origin for the purpose of providing detailed ancestry information. So the focus of the project is on South Asians: Indians, Pakistanis, Bangladeshis and Sri Lankans.

The project will collect 23andme raw genetic data from participants to better understand the ancestry relationships of different South Asian ethnicities.

I have named it after Harappa, an archaeological site of the Indus Valley Civilization in Punjab, Pakistan.”

There was a nice deal running on 23andme about a month ago for their ancestry & health kit that worked out to be $160 for 1 year. I hopped on board, got my kit, spat in the tube and sent it off. It is currently being analyzed. My ancestry is one of the populations Zack is looking for — so I’ll be sending my data to him. I can’t wait.

If you have had a 23andme genetic testing, you should consider participating in this project. It looks to be very interesting.

Razib has done rounded up a nice review of Dienekes‘ Dodecad data to answer some prelim questions on the genetic of Ethiopia. Ethiopia is a very interesting cultural and paleontological area of the world. I had the pleasure of being a part of a field group several years ago and had a wonderful time. A good summary of the ADMIXTURE analysis done by Dienekes, reorganized by Razib, is shown below:

I don’t have much to add to his post, other than to hand you over there and to check it out. You may also wanna read more about the Dodecad Ancestry Project in this Nature News piece.

Do you believe in evolution?  Forty percent of Americans don’t (more on that later).  A student asked me this question on day one of the first introductory anthropology class I ever taught.  I believe that any difficult-to-answer question is a good one, and this one baffled me with its simplicity.

Short answer: yes, I believe in evolution…but why was a modern college student in the United States asking me this?  The student was intelligent, curious, and friendly.  If anyone was naive, it was me for not expecting the question.  He’d simply been shaped by our culture to see evolution as a divisive matter of public opinion – and he wanted to know where I stood on the issue.  It would have been easiest to take his question at face value, answer yes, and move on to discussing the details of human evolution.  But, like so many idealistic teachers, I grasped the “teachable moment” and ran with it (annoying the many students who already believed in evolution and wanted to get into the good stuff):

• Science is an empirical method that (at least ideally) is not based on belief.  All scientific conclusions are tentative.  Scientific knowledge is evidence-based, ever-growing, and self-correcting since new or contrary evidence can be discovered at any time.  When asked what evidence would convince him that evolution was false, biologist J.B.S. Haldane remarked “Fossil rabbits in the Precambrian.”  Like all scientifically-testable ideas, evolution is falsifiable.  If rabbit fossils are found in Precambrian layers of rock (millions of years too early), I’ll be happy to explore alternative theories!
• There is also a major difference between the general and scientific uses of the word theory.  In everyday usage, theory means a guess or speculation.  In science, a hypothesis does not rise to the level of a theory without overwhelming evidence and explanatory power.  Anti-evolutionists dismiss evolution as “just a theory,” but scientifically-speaking, this is a gracious compliment.  Charles Darwin’s theory of evolution by natural selection has survived 150 years of rigorous challenges in every field from geology to genetics.
• Evolution may be politically, culturally, and emotionally controversial.  In the 19th Century, Darwin’s “dangerous idea” caused spiritual crises for many.  However, in the 21st Century, biological evolution is not scientifically controversial.  It’s an understatement to say that the evidence for evolution is overwhelming.
• Finally, scientific inquiry has revealed other phenomena that I “believe” in.  I believe in a round earth, though my senses tell me it’s flat.  I believe that the earth orbits the sun, not the other way around.  I believe in sexual reproduction, not the stork theory of baby origins.  I believe in particles like quarks, though I can’t see them directly.  And I do believe in evolution.

That’s a pretty long preamble, and one that most of my students had heard in middle school or high school biology classes.  Still, I thought “Do you believe in evolution?” deserved a thoughtful answer.  These days, I might answer “Yes.  Please read Jerry Coyne‘s Why Evolution is True” to save time.  After that, we were able to move into the actual evidence for evolution, all the cool hominid skulls, etc.

Assuming that Precambrian rabbits, or comparable out-of-place fossils, aren’t found anytime soon, the reality of evolution has been scientifically proven beyond a reasonable doubt.  So, it’s no longer necessary for anthropologists to summarize the scientific method before discussing human evolution, right?  Unfortunately, in the United States, evolution is still presented as if it was a political issue and, in some cases, it does enter the political arena (e.g., school board decisions).  Informed people can have differences of opinion over political issues.  In fact, one thing that ties Americans together is the core belief that political issues should be decided democratically.  But evolution is a scientific theory, subject to empirical evidence, not public opinion…and that may be a good thing.

Gallup poll results from December 17, 2010 show that 40% of Americans believe that “God created human beings pretty much in their present form at one time within the last 10,000 years or so.”  Make no mistake, the last 10,000 years have been a fascinating part of the human story – but they’re not the whole story!  Poll results like these make me feel both discouraged and reflective.  How is this possible in a developed country with educational opportunities like ours?  What can I do to better explain the human past (ALL of it)?  There is some truth to the argument that more and better education would help.  The same Gallup poll divides anti-evolution respondents by education level:

Gallup Poll on Evolution vs. Education

So education helps, but education alone cannot overcome the cultural/religious impediments that prevent more widespread understanding of biological evolution in the U.S.  Undoubtedly, many of the survey respondents took biology or anthropology as part of their education and still hold the belief that humans are new and separate from all other forms of animal life.  One hopeful sign is that 40% is the lowest percentage of “creationists” in Gallup’s history of asking this question – down from a high of 47% in 1993 and 1999.  There will probably always be a percentage of the population that is beyond the reach of evidence, especially with an emotionally-charged subject like evolution (after all, no one is freaking out about teaching gravity in public schools).

For cultural and historical reasons too numerous to go into here, Americans are not yet ready to embrace Darwin’s grand view of life – a view that has become so much grander and more elegant over the last 150 years.  It might take another 150 years for the culture to catch up with the science.  Those of us who love the science of humanity will keep doing our part to share the evidence for evolution and its role in shaping our species.

Do you believe in evolution?

Neandertals have long been touted as a species with “hyperarctic” adaptations. Their stout proportions and shortened distal limb segments are often explained to conserve heat. Similarly, the Neandertal cranium is traditionally said to be cold adapted. An article released on December 22^nd in the Journal of Human Evolution challenges these traditional notions, specifically those about Neandertal nasal adaptations.

The Neandertal nasal apparatus has conventionally been cited as cold adapted mainly because of the enlarged sinuses. The authors of this article, among them Chris Stringer, cite evidence that larger sinuses are not in fact typical of cold weather mammalian species.

Through observation of human populations and studies on other mammals, cold weather is more highly correlated with smaller sinuses. That is, animals from more northerly locations typically have smaller sinus cavities. As an example taken from lab studies, rats raised in colder conditions also show smaller sinus cavities.

But are Neandertal sinuses even large, as is typically maintained? The authors of this paper argue that there is nothing large about them. Through examination of Neandertal remains, the sizes of the frontal and maxillary sinuses actually fell within the range of Homo sapiens from temperate climates.

The Forbes’ Quarry Neandertal (left) and H. sapiens skulls. Frontal sinus in purple, maxillary sinus in red. Photo from Rae et al., 2010.

This study is very suggestive that Neandertal nasal anatomy is not due to cold weather adaptation. To be cold weather adapted, the sinuses would be smaller and not larger, as many anthropologists have maintained since the first remains were discovered. Not only are the sinuses not small, they are not large- which speaks to a larger problem. How many other basic assumptions do we take as fact just because they have been around for so long?

If not cold weather, what could have caused the differences in facial anatomy between H. neanderthalensis and H. sapiens? The authors of this paper do not offer many answers, but offer a couple of possibilities. Differences in masticatory stress (utilizing teeth as a tool, for example), or genetic drift are two potential reasons discussed.

This paper may be taking another step in overturning traditional understanding of Neandertals as a cold weather species. Generations of anthropologists have passed knowing that Neandertals differed in facial anatomy due to cold weather adaptation, unsubstantiated by data.

Rae, T.C., Koppe, T., Stringer, C.B. (2010).  The Neanderthal face is not cold adapted.  The Journal of Human Evolution. Article in Press.

Image via Wikipedia

A Homo floresiensis premolar will be drilled, and DNA extracted, according to a Nature News piece passed on by Razib, John Hawks, and Dienekes. This is not the first attempt at extracting hobbit DNA, the news article explains,

“Five years ago, two teams, one from ACAD and one from the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, attempted to recover DNA from another H. floresiensis tooth excavated in 2003. Both attempts failed.

Now, a team led by Christina Adler, a geneticist at ACAD, has found that standard sampling procedures could be responsible for the failure to get DNA from the hobbit and some other ancient specimens.”

I’ve been out of the loop for a couple years and have lost track on the advances made in ancient DNA studies. I do remember there was a big hub-bub regarding contamination from excavators and degradation of DNA. Maybe some of the new techniques overcomes these problems.

The lead, Adler, recently published a paper on the advances, titled, “Survival and recovery of DNA from ancient teeth and bones.” Again, I don’t have time to read it and give you a summary because I am studying for my board exams. It seems like the paper advises extracting DNA from the cementum of teeth which has way more DNA than the normal source of aDNA, dentin… But if you’re curious about ancient DNA sequencing, this should be an interesting read.

Nonetheless, it should be very interesting to see what comes from this attempt. I wish the team the best of luck and eagerly await the results.

The American Anthropological Association (AAA) is a strange organization. I often wonder how it operates, but then I realize I don’t even wanna know because there’s often no real logic to their madness. Take into consideration these cases:

Case 1: About 4 years ago the AAA decided to close access to almost all their journals, directly against the Federal Research Publication Access Act. This spurned a lot of discussion regarding ownership of publication, author’s rights and the AAA’s motivation behind it. Most of us wondered how could the AAA, who didn’t fund the research, produce the data, and write up the analysis, close off the information to the world? Here was a bit of my outcry over the matter, archived by afarensis in June of 2006,

“The hypocrisy that surrounds the AAA when it begged for anthropologists to protest to the US government to not cut funding but their recent resiliency to not give back is outstanding in this matter. I don’t get why the AAA won’t open their eyes and see that this form of publishing helps to ensure long-term access to scholarly articles. Unlike articles that are licensed in traditional article databases, like their closed AnthroSource, public libraries and institutions of the people (like universities) can create local copies and repositories of these resources. People, by working together to make repositories of open access literature, can ensure continued access to these scholarly publications into the distant future.”

From this idiocy, a nice project spun off but hasn’t in my opinion been a viable alternative. Unfortunate.

Case 2: Once upon a time the AAA was an organization that scoffed at social media and Web 2.0, specifically blogs. It’s hard to dig up exact references since many links have died… But I do distinctly remember them issuing a statement saying blogs are useless forms of communication, with a little wink wink nod nod to this said blog.

When they redesigned their homepage a couple of years ago, they deployed several blogs. They even sent me emails asking for link exchange. Sure people are allowed to change their minds, but I wondered what’s with the change in heart? Suffice to say, I didn’t add them back.

Case 3: The AAA just had their annual meeting and yes, everyone’s reporting that decided to do away with science. It’s true, Peter Wood of the Chronicle, writes on them actively deciding to nix science out of the Mission Statement. I’ve copied and pasted the presumed edits to the mission statement he provided below the read more link.  Another related decision made is defining the role of AAA, away from ethnography and scientific experiments and observations to anecdotal and subjective journalism… Again without ethnology and ethnography — what is cultural anthropology?

Alice Dreger of Fetishes I Don’t Get, writes on some of the anger she experienced from other scientific anthropologists,

“The primatologist Sarah Hrdy (a member of the National Academy of Sciences) wrote, “My reaction is one of dismay-actually, even more visceral and stronger than that-albeit not surprise.” The scientists I talked to want to know (as I do) exactly what is the AAA Executive Board’s justification for all this. They are confused about whether they should bother to fight, or just give up and depart the AAA already.”

The Society for Anthropological Sciences, a division of the AAA, objected to these changes, I am sure most do. I don’t understand why this change is being done. In a time and age when we need to strive to objective data to make informed decisions, this organization is moving away from that, and consciously. Why?

Could it because anthropology is largely not considered a science outside of the discipline — so the AAA chooses embrace what most think of us?

Again it is hard to get into the minds of such a dysfunctional organization. They seem to never make the right decision. An analogy that works in my mind is the AAA is to anthropologists as the Clerical Theocracy of the Islamic Republic are to Iranian population. As many governments help make decisions to move forward and advance their society, both the AAA and the mullahs regress their organizations further back in time.

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Well, I feel somewhat vindicated. Remember the post where I criticized hominin cut marks from over 3 million years ago? Others have also had an eye of suspicion and have published their concerns in PNAS this week.

I was wrong in considering the croc marking differential to the cut marks. But I was not wrong in thinking they author of the original paper made the wrong conclusions. The authors of this new paper raise up an even more logical explanation, and carried out a more thorough analysis. Here’s part of their argument from the abstract,

“The Dikika research group focused its analysis on the morphology of the marks in question but failed to demonstrate, through recovery of similarly marked in situ fossils, the exact provenience of the published fossils, and failed to note occurrences of random striae on the cortices of the published fossils (incurred through incidental movement of the defleshed specimens across and/or within their abrasive encasing sediments). The occurrence of such random striae (sometimes called collectively “trampling” damage) on the two fossils provide the configurational context for rejection of the claimed butchery marks. The earliest best evidence for hominin butchery thus remains at 2.6 to 2.5 Ma, presumably associated with more derived species than A. afarensis.”

Trampling vs. Cut Marks (The image in A is courtesy of R. Blasco and J. Rosell. The images in B, D, and F are modified from McPherron et al.)

Looking back at the comment thread, I got a lot of flak. Aside from being wrong about the croc markings, I won’t deny that my post was inflammatory and incited a lot of the response. But many who know just a bit about the fossil and archaeological record, may find it extraordinary to believe australopithecines were using stone tools to extract food from flesh and bone from ‘indirect’ evidence. Of more concern was the lack of exhaustive exploration into other possibilities.

I remember as an anthropology undergrad one of my professors designed a hands-on experiment for us. If memory serves me correctly, this was for a zooarchaeology class. She acquired some beef bones from the local butcher and gave us stone tools. We were instructed to extract the marrow from the bones. We hammered the afternoon away.

Part of our assignment was to use different techniques and tools. We could cut, saw, abrade, chisel, etc. After the mess was done we compared our extractions from prehistoric samples. This comparative approach allowed use to systematically compare how we modified the bone to how possibly prehistoric individuals modified bone.

The authors of the current PNAS paper did something similar. The hypothesized that trampling could have created similar modifications as seen on the 3.39 million year old Dikika bones. And what did they do? Well they got some bone and experimentally setup some trampling experiments. As one would expect, cut marks would have a \/ shaped incision. Incidentally, the bones from Dikika show a \_/ flat bottom morphology. The authors write,

“Ninety-six percent of experimental trampling grooves display a broad-based, open cross-section with the aforementioned shape, versus just 4% of experimental grooves inflicted by simple (i.e., unmodified) stone flakes used to cut meat from bones. In addition, curvy and sinuous groove trajectories characterize nearly 70% of experimental trampling marks,compared with just 10% of experimental cut marks created with simple flakes (11). Together, these experimental results provide a robust actualistic context to evaluate illustrated marks F, G, H2,and I on DK-55–3 as high-probability trampling damage and not stone tool cut or percussion marks…”

I wonder what happened to good science?

What happened to the scientific method?

Did we not learn how to set up experiments and carry out analysis?

How can a paper make all the way into Nature and not exhaust all the possibilities?

These are not rhetorical questions. I am seriously asking it. I honestly feel that there is something rife in paleoanthropological studies lately. I must sound like a broken record to say yet again, too often are papers published in haste and for fortune and glory… All which compromise the validity & ethical responsibility of the science.

Domínguez-Rodrigo M, Pickering TR, & Bunn HT (2010). Configurational approach to identifying the earliest hominin butchers. Proceedings of the National Academy of Sciences of the United States of America PMID: 21078985

Several views of a human jawbone and molars found in a Chinese cave.

National Geographic is running news that Erik Trinkhaus and others have published the findings of the oldest modern human outside of Africa, specifically in China. Not much is given on the locality and specifics of the fossil, but the article does state that the fossil mandible fragment and teeth are 60,000 years older than any other modern human fossil. That leads to some curious questions of interbreeding with other Homo species and curiosities about the presence of modern humans that did not ‘act’ modern… In other words, the archaeological record isn’t quite on the same page.

Hawks hasn’t posted on the paper and find yet, but he is quoted in the National Geographic article saying the mandible dimensions are within range of both Neandertals and modern human. Unsurprisingly, the Out of Africa theory is challenged. I still don’t know what to think of it all, the chin does look very robust.

The PNAS article is not yet published at the time of the National Geographic writing and me blogging this post. Seems like people are still jumping publication embargoes. I shouldn’t have to call out what a cheap shot it is to have sensationalist news getting out before the first hand reports do. I guess things will never change. So until I get my hands on the real paper, I’m just calling it as others are reporting it.

I don’t know who this is worse for, the editors & reviewers over at Nature or the authors of the article who can’t tell the difference between crocodile teeth markings and stone tool modification, nor raise the possibility. The paper, “Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia,” very confidently proclaims unambiguous evidence for,

“stone-tool-inflicted marks on bones found during recent survey work in Dikika, Ethiopia, a research area close to Gona and Bouri. On the basis of low-power microscopic and environmental scanning electron microscope observations, these bones show unambiguous stone-tool cut marks for flesh removal and percussion marks for marrow access.”

Butchered by early humans or eaten by crocodiles? Image: David DeGusta

Given that the said rib fragment, DIK-55-2, came from a prehistoric lacustrine site. These markings could have been produced by crocodiles. Crocs, if you aren’t aware of (ahem editors and publishing group) are very abundant in the Rift Valley — both currently and prehistorically. On top of that, crocs like to eat meat and scavenge. Yes its true, they are carnivores. Australopithecines were at most ominivores, with wide based teeth useful in grinding tubers and nuts. Crocs have more meat shearing, bone crushing teeth than 3.39 million year old stone tools, which there are none of at the moment.

Given that there really isn’t an archaeological record for Australopithecine tools, I’ll take a gander and say crocs like to eat meat and scavenge more effectively than A. afarensis could make and use said tools to butcher a large ungulate. They have been on this Earth for roughly 197 million years more than hominins have and they are really good at what they do… Again, probably better than a species of hominins who did not live in the Stone Age. It is just as likely (if not more) that the markings were produced by crocodiles just given the ecological context.

Now just how different at cut marks from crocodile teeth marks? David DeGusta, from Stanford University, compared and contrasted the two different markings using images from Njau and Blumenchine (2006) paper titled, “A diagnosis of crocodile feeding traces on larger mammal bone, with fossil examples from the Plio-Pleistocene Olduvai Basin, Tanzania,” to those published in the current Nature article. I’ve inserted DeGusta’s image into this post on right for your own inspection. DeGusta was also on Science Friday, discussing this possibility, with one of the article’s authors, Zeresenay Alemseged. What do you think? Do they look completely different or similar? Seriously, I am asking you to comment. I’d like to know what you see.

Personally I don’t see much of a difference. I agree that stone tools marks are more V shaped, while croc teeth are more pitted/rounded. But take this into light: tool use, especially butchery, is a very human behavioral trait. In their search to attribute this human behavior to a primitive hominin species who roamed 800,000 years earlier, to the era of Australopithecus afarensis, without considering another possible explanation, the authors and editors of Nature were somewhat foolish.

Many paleoanthropologists are in this mad rush to claim their precious find is the most human of hominins, so as to etch their name into the textbooks in rewriting human evolution, that they sometimes forget about doing thorough comparative science. And many publications are in this mad rush to publish the most human of findings, that they sometimes forget about thoroughly editing scientific works. Think that could be the case? I sure do… Why should we settle on secondary evidence for Australopithecine stone tools when none have been found yet, and when another possibility hasn’t been extensively exhausted?

McPherron, S., Alemseged, Z., Marean, C., Wynn, J., Reed, D., Geraads, D., Bobe, R., & Béarat, H. (2010). Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia Nature, 466 (7308), 857-860 DOI: 10.1038/nature09248