The Journal of Experimental Biology has published an interesting paper about some unique features in sprinters: longer toes and shorter ankle joints. The only one flaw is that their sample size is limited, they only compared 12 collegiate sprinters with 12 non-athletes of the same height. Regardless, from a physical anthropological point of view, this comparative & biophysical analysis informs us what traits help humans sprint faster.

The significance of long toes and short ankle joints can be explained from a purely physics perspective. From the start of a sprint, the only way a human can accelerate is through the transfer of energy from the force of the leg muscle to pushing on the ground. The advantage of longer toes provide maximum contact with the ground just a little bit longer than shorter toes.

The ankle joint is shorter because there is an inverse relationship between tension force and distance — think torque and angular momentum. Sprinters have a 25% shorter distance between the Achilles tendon and center of rotation of the ankle. The Achilles tendon is the common attachment of the gastrocnemius and soleus muscles into the calcaneus. When contracted, these two muscles flex the knee and plantar flex the foot. With a shorter ankle joint, these muscles shorten less for the same joint rotation. If muscles shorten less, then they shorten more slowly. This facilitates them to produce greater force that more than compensates for the reduced leverage.

When these two adaptations are combined, the authors figured that the greatest acceleration is achieved when the Achilles tendon lever arm is the shortest and the toes are longest. Comparing these anatomical features to other sprinting animals, like ostriches, greyhounds and cheetahs, they authors observed that they also have feet built for sprinting with similar features.

The authors, who are not physical anthropologists, state in press releases that they think these adaptations could have had some evolutionary backing. They raised the tired hypothetical scenario where early human ancestors, now those with longer toes and shorter ankle joints, were better able to run away from the saber tooth tiger or marauding tribe and reproduce that trait. But I disagree, while there certainly is an inherited component to the size and shape of our bones, muscles, and joints, our bodies are malleable and depending on training, our bones and muscles can change!

Furthermore, the majority of humans are not sprinters, as I understand it. In fact, most of us are good at long distance motility. Our bodies are extremely inefficient at sprinting but we’re really good at staying the course! Most of us have lots of Type I muscle fibers, slow but fatigue resistant fibers. Anyways, I don’t mean to rag them on this concept, as I mentioned they aren’t physical anthropologists and they seem to only be speculating on this last point. Either way, I believe the observation they made is interesting!

Knight, K. (2009). SHORT HEELS GIVE ELITE SPRINTERS THE EDGE Journal of Experimental Biology, 212 (22) DOI: 10.1242/jeb.039735

Lee, S., & Piazza, S. (2009). Built for speed: musculoskeletal structure and sprinting ability Journal of Experimental Biology, 212 (22), 3700-3707 DOI: 10.1242/jeb.031096

Claude Lévi-Strauss died two days ago. He was 100 years old.

I shouldn’t have to write about his impact to the field of anthropology, in summary it was profound. He authored many texts. He set forth structuralism, a mode of thought by which we can compare relationships between social systems. His contributions to studying cultures and anthropology were deep and he will be missed.

Ciarán Brewster, a.k.a. adhominin, just tweeted about three book reviews. The reviews, written by Robin McKie of The Observer, cover recent books on cooking and human evolution which were written by some pretty big names in anthropology:

• Catching Fire: How Cooking Made Us Human by Richard Wrangham
  Wrangham’s thesis is that the advent of cooking reduced our energy demands of actually chewing, we do have a smaller muscles of mastication, jaws and teeth. This shift diverted the energy we would be spending on the act of eating, along with eating more easily digestable nutrients, to developing massive brains. Something I didn’t know and learned in the reviews is that people who eat only on uncooked meat or veggies will slowly starve, sucks for those on the raw food diet.
• The Well-Dressed Ape: A Natural History of Myself by Hannah Holmes
  Holmes addresses the fact that human females are the only primates with enlarged breasts and discusses theories on why. She says that the large breasts allow more feeding time for infants, which kept the babies more compliant and less likely to cry, which would otherwise attract predators. Our relatively hairless skin also evolved as a direct function of predator pressure, early human ancestors needed greater surface area to cool off our skin with sweat as they ran from predators in the savannah.
• The Humans Who Went Extinct: Why Neanderthals died out and we survived by Clive Finlayson
  Finlayson discusses why and possibly how Neandertals were so easily replaced by modern humans. He argues that the harsh landscape of early Africa, about 100,000 years ago, when modern humans emerged forced them to learn new technologies and lifestyles that were, “more inventive and intelligent as they struggled for survival. European Neanderthals, untutored in the school of hard knocks, were no match for our ancestors when they met.”

These books seem to be entertaining, you should check them out if you haven’t already. Also, if you’re on Twitter and looking to follow some active anthropology minded folks, I’ve compiled what I believe to be a pretty comprehensive list of anthropology Twitterers. Check that out too, and follow it… If I’m missing anyone please let me know on Twitter or via this post’s comment thread.

October 2nd 2009 Cover of Science Magazine

There’s more than 11 citations here, but the others are associated news and media covered by Science. They’ve even dedicated a special issue to it. Very impressive thorough volume of information. Now you have a some understanding why it took so long to publish… Anyways get to reading.

News Focus

Gibbons, A. (2009). A New Kind of Ancestor: Ardipithecus Unveiled Science, 326 (5949), 36-40 DOI: 10.1126/science.326_36

Gibbons, A. (2009). Habitat for Humanity Science, 326 (5949), 40-40 DOI: 10.1126/science.326_40

Gibbons, A. (2009). The View From Afar Science, 326 (5949), 41-43 DOI: 10.1126/science.326_41

Introduction & Video

Hanson, B. (2009). Light on the Origin of Man Science, 326 (5949), 60-61 DOI: 10.1126/science.326_60a

N/A (2009). Video: The Analysis of Ardipithecus ramidus–One of the Earliest Known Hominids Science, 326 (5949), 60-60 DOI: 10.1126/science.326_60b

Research Articles

White, T., Asfaw, B., Beyene, Y., Haile-Selassie, Y., Lovejoy, C., Suwa, G., & WoldeGabriel, G. (2009). Ardipithecus ramidus and the Paleobiology of Early Hominids Science, 326 (5949), 64-64 DOI: 10.1126/science.1175802

WoldeGabriel, G., Ambrose, S., Barboni, D., Bonnefille, R., Bremond, L., Currie, B., DeGusta, D., Hart, W., Murray, A., Renne, P., Jolly-Saad, M., Stewart, K., & White, T. (2009). The Geological, Isotopic, Botanical, Invertebrate, and Lower Vertebrate Surroundings of Ardipithecus ramidus Science, 326 (5949), 65-65 DOI: 10.1126/science.1175817

Louchart, A., Wesselman, H., Blumenschine, R., Hlusko, L., Njau, J., Black, M., Asnake, M., & White, T. (2009). Taphonomic, Avian, and Small-Vertebrate Indicators of Ardipithecus ramidus Habitat Science, 326 (5949), 66-66 DOI: 10.1126/science.1175823

White, T., Ambrose, S., Suwa, G., Su, D., DeGusta, D., Bernor, R., Boisserie, J., Brunet, M., Delson, E., Frost, S., Garcia, N., Giaourtsakis, I., Haile-Selassie, Y., Howell, F., Lehmann, T., Likius, A., Pehlevan, C., Saegusa, H., Semprebon, G., Teaford, M., & Vrba, E. (2009). Macrovertebrate Paleontology and the Pliocene Habitat of Ardipithecus ramidus Science, 326 (5949), 67-67 DOI: 10.1126/science.1175822

Suwa, G., Asfaw, B., Kono, R., Kubo, D., Lovejoy, C., & White, T. (2009). The Ardipithecus ramidus Skull and Its Implications for Hominid Origins Science, 326 (5949), 68-68 DOI: 10.1126/science.1175825

Suwa, G., Kono, R., Simpson, S., Asfaw, B., Lovejoy, C., & White, T. (2009). Paleobiological Implications of the Ardipithecus ramidus Dentition Science, 326 (5949), 69-69 DOI: 10.1126/science.1175824

Lovejoy, C., Simpson, S., White, T., Asfaw, B., & Suwa, G. (2009). Careful Climbing in the Miocene: The Forelimbs of Ardipithecus ramidus and Humans Are Primitive Science, 326 (5949), 70-70 DOI: 10.1126/science.1175827

Lovejoy, C., Suwa, G., Spurlock, L., Asfaw, B., & White, T. (2009). The Pelvis and Femur of Ardipithecus ramidus: The Emergence of Upright Walking Science, 326 (5949), 71-71 DOI: 10.1126/science.1175831

Lovejoy, C., Latimer, B., Suwa, G., Asfaw, B., & White, T. (2009). Combining Prehension and Propulsion: The Foot of Ardipithecus ramidus Science, 326 (5949), 72-72 DOI: 10.1126/science.1175832

Lovejoy, C., Suwa, G., Simpson, S., Matternes, J., & White, T. (2009). The Great Divides: Ardipithecus ramidus Reveals the Postcrania of Our Last Common Ancestors with African Apes Science, 326 (5949), 73-73 DOI: 10.1126/science.1175833

Lovejoy, C. (2009). Reexamining Human Origins in Light of Ardipithecus ramidus Science, 326 (5949), 74-74 DOI: 10.1126/science.1175834

Ardipithecus ramidus

I want to be the first to break news to you that Science has published White’s contentious 4.4-million-year-old Ardipithecus ramidus! I caught news of the release on the internet. The link is not live yet, but when it is I’ll fill you in.

Owen Lovejoy is one of the authors of the paper, and he says that the fossil changes the notion that humans and chimps, our closest genetic cousins, both trace their lineage to a creature that was more like today’s chimp and we’ll have to be rewriting our text books soon. This is big folks. What this means is that our common ancestor was a bipedal forest forager and that chimps were an evolutionary offshoot.

White, the lead author, describes the fossil with flexible hands and a brain about a quarter the size of a human’s,

“We can’t say this species was a direct ancestor of modern humans, so we have to be careful. But it suggests that the direction of early hominids was away from the chimp.”

There are a lot of other implications that I won’t get into just yet, but keep checking us out from time to time as we get more!

Here are some of the press releases/news coverage that have come out since I’ve published this post:

• Kent State University Professor C. Owen Lovejoy helps unveil oldest hominid skeleton
• Fossil finds extend human story
• Before ‘Lucy,’ there was ‘Ardi’: First major analysis of early hominid published in Science
• Oldest hominid skeleton provides new evidence for human evolution
• Humanity Has a New 4.4 Million-Year-Old Baby Mama
• Ancient Skeleton May Rewrite Earliest Chapter of Human Evolution
• Fossil Skeleton From Africa Predates Lucy
• Ethiopian desert yields oldest hominid skeleton
• Ardi displaces Lucy as oldest hominid skeleton
• Fossil Primate Ardipithecus Ramidus Described (Finally)
• Oldest “Human” Skeleton Found–Disproves “Missing Link”
• ‘Ardi,’ Oldest Human Ancestor, Unveiled

The latest issue of the Proceedings from the National Academy of Science journal hosts a Out of Africa: Modern Human Origins special feature for free online. I recommend you check it out.

September 22nd, 2009 Cover of the PNAS Out of Africa: Modern Human Origins Special

• Editorial by Richard G. Klein, “Darwin and the recent African origin of modern humans.”
• Perspective by Ian Tattersall, “Human origins: Out of Africa.”
• Perspective by Timothy D. Weaver, “The meaning of Neandertal skeletal morphology.”
• Research Article by J. J. Hublin, “The origin of Neandertals.”
• Research Article by Michael P. Richards and Erik Trinkaus, “Isotopic evidence for the diets of European Neanderthals and early modern humans.”
• Research Article by John F. Hoffecker, “The spread of modern humans in Europe.”
• Research Article by G. Philip Rightmire, “Middle and later Pleistocene hominins in Africa and Southwest Asia.”
• Research Article by Francesco d’Errico, et al., “Additional evidence on the use of personal ornaments in the Middle Paleolithic of North Africa.”
• Research Article by Michael DeGiorgio, et al.,”Explaining worldwide patterns of human genetic variation using a coalescent-based serial founder model of migration outward from Africa.”

Unfortunately, I have not yet had the time to read any of these papers but they I reckon they should be somewhat enlightening.

I recently completed a medical parasitology course as part of my medical education. One of the diseases we discussed was leishmaniasis. Leishmaniasis is a zoonotic disease that is transferred to humans from reservoir hosts via the sand fly vector. The sand fly injects the promastigote form of the parasite, and the parasite invades white blood cells and proliferates as amastigotes.

The amastigotes erupt out of white blood cells and the Leishmania parasite can cause three different types of symptomatology: visceral, cuteanous, or muscocutaneous. Leishmania donovani causes visceral problems, specifically Kala-azar, an irregular fever accompanied with an enlarged spleen and/or liver, anemia, diarrhea, etc. ultimately to death. L. donovani is found more or less globally. There are two other types of cutaenous causing Leishmania spp., Leishmania major and Leishmania tropica. Both of which cause lesions to the skin and are found in the Old World but the latter causes dry ulcers and the former, wet, serious ulcers.

Leishmania braziliensis (L. selvática) causes muscutaenous lesions, and as the name suggests is a New World disease. This is the parasite behind Espundia or Uta leishmaniasis, a horribly disfiguring and painful disease where very destructive oral/nasal lesions develop after 3-20 years of infection. Sloths and tropical rodents are the reservoir hosts for the L. braziliensis parasite.

San Pedro de Atacama, Chile

As I mentioned, I just finished this parasitology class and so the information has been fresh in my head. This morning as I was reading my RSS feeds, I noticed a new open access PLoS One paper on the discovery of 4 cases of leishmaniasis in ancient remains recovered from the archaeological cemetery of Coyo Oriente, in the desert of San Pedro de Atacama, Northern Chile. The paper is titled, “Ancient Leishmaniasis in a Highland Desert of Northern Chile,” and authored by Chilean, Canadian and U.S. researchers. Upon reading the abstract, I was immediately drawn in because the discovery of leishmaniasis in this arid desert gives insight to ancient traditions. Even though the remains are relatively new, about 1,000 years old, these come from a time period when the Americas were not contacted by Europeans and not much is known about these people.

Four Individuals with Leishmaniasis from Coyo Oriente, Chile

The remains recovered yielded 4 individuals, all middle aged females (though sex determination was not made on pelvic bones), with massive bone destruction to the face. Other diseases such as osteocarinoma, leprosy, trepanosomiasis, Yaws disease, and tuberculosis can cause such lesions so the authors decided to screen the bone to find any genetic markers of the pathogen. Cloning and sequencing indicated that the researchers were looking at the handy work of the Leishmania parasite, but the sequence differs from Old World Leishmania spp. It could not be confirmed if it was modern Leishmania braziliensis (L. selvática), but looking from the osteological pathology… I’d guess it to be safe to assume these individuals were infected by L. braziliensis.

As indicated earlier this is a curious finding, because L. braziliensis needs tropical mammals, like the sloth, as a host. There have been no sloths in the 20 million year old rainless Atacama desert. This means that two situations could have happen,

“infected individuals could have been natives of San Pedro de Atacama who traveled to the endemic zone, were infected with Leishmaniasis and then returned to their native high altitude desert. Alternatively, they could have been natives of the distant endemic area who migrated to San Pedro de Atacama after they became infected. The long incubation period between infection and the development of destructive facial and boney lesions–up to 20 years —would have allowed plenty of time for infected travelers to complete their journey before they became debilitated.”

What we do know is the people of the Atacama desert, the Atacameños, and the people of the Yungas, in the Eastern Andes of Argentina exchanged of goods during this time period. The commerce presumably increased the amount of foreigners into the Atacama Desert leading to the possibility of patrilocality and intermarriage and kinship bonds between high altitude desert people and lowlanders from tropical areas. Considering that these 4 individuals are middle aged females it is very likely that they were foreigners who relocated, if not intermarried into Atacama culture, and were infected with leishmaniasis at an early age in their more tropical origins.

While there are a couple leaps of faith in this paper, the weak sexing of the individuals, and only one loci (LDR3) was sequenced to usable quality to diagnose a Leishmania infection, they no doubt had bony lesions — most likely leishmaniasis that did not originate in the Andean deserts but from tropical lowlands. At the very minimum this paper demonstrates people in pre-contact Chile had extensive trade networks, not only were they exchanging goods but also disease and possibly genes.

I really enjoy reading these sorts of papers when time permits, as they spark my interests both in medicine — in this case a form of ‘paleopathology’, anthropology and genetics. I suggest you have a read of this open access paper and let me know what you think of it… I’ve covered Andean archaelogical finds before but I am interested to know more about prehistoric Andean cultures. So if you got some to share about the Atacameños, Yungas, etc. please do.

Costa, M., Matheson, C., Iachetta, L., Llagostera, A., & Appenzeller, O. (2009). Ancient Leishmaniasis in a Highland Desert of Northern Chile PLoS ONE, 4 (9) DOI: 10.1371/journal.pone.0006983

The current issue of the Journal of Neurodevelopmental Disorders has published an open access paper announcing the discovery of a new candidate gene linked to language, KIAA0319. The paper is titled, “Convergent genetic linkage and associations to language, speech and reading measures in families of probands with Specific Language Impairment.”

The gene sits on short arm of Chromosome 6. Through linkage analysis, it was found to be associated with variability in language abilities in a study of children with Specific Language Impairment (SLI) and their family members, as well as with variability in speech and reading abilities. Specific alleles were confirmed with association analysis.

“A total of 322 participants, including 86 probands, 134 siblings, and 102 parents and other relatives were tested from an ongoing longitudinal study of Specific Language Impairment… The significant results cluster in the 5’ region of KIAA0319… In particular, we replicate the associated alleles for rs4504469 (allele C); rs761100 (allele G); rs6935076 (allele T) and rs3756821 (allele A).”

It should be noted that KIAA0319 was already linked to dyslexia in previous studies. But, in this paper, the pleiotropic effects of KIAA0318 alleles on language ability, speech impairments, and text comprehension were correlated.

Rice, M., Smith, S., & Gayán, J. (2009). Convergent genetic linkage and associations to language, speech and reading measures in families of probands with Specific Language Impairment Journal of Neurodevelopmental Disorders DOI: 10.1007/s11689-009-9031-x

Scientific American recently published a spineless attack on the state of access to paleoanthropological specimens. They titled it, “Fossils for All: Science Suffers by Hoarding,” and John Hawks lend it credibility with a nod in his post. Aside from being spineless, it reeks of ignorance and is tactless. In this post I’ll be discussing why this is not a honest criticism but rather a sloppy slam.

If you read the piece, you’ll notice that Tim White is in the cross hairs of the editors of Scientific American. Why? Tim White discovered Ardi­pithecus ramidus fifteen years ago and continues preparing the specimens. For the editors, that’s enough to pull the guns out and start shooting — claiming he’s sitting on his golden egg far too long and damaging the field as a whole. The cowards at Scientifc American decided to make this bold claim behind a wall of anonymity… publishing this piece simply as the editors. And here in lies the drama and the conflicts of interest.

See, most anthropological editorials on Scientific American are authored by Kate Wong, a twelve year veteran editor for magazine. She is their anthropology editor. Her authority on the subject matter come from a Bachelor’s degree in physical anthropology and zoology from the University of Michigan. University of Michigan is home to Milford Wolpoff, the man who supports multiregional evolution hypothesis… You know the one that claims the origins of Homo sapiens happened in multiple places around the world and not from a common African origin. He’s known for not being a field scientist. Furthermore, within the discipline, the rift between Wolpoff and White is pretty well known and deep. White got his PhD from the University of Michigan. And Wolpoff holds a ~50 year grudge against White in regards to his stance against his single species origin of humans.

Wong has worked closely with another large anti-Tim White camp, the Hadar folks, during the lead up to the Selam news frenzy that we talked about several years ago. The Hadar camp is more or less a Donald Johanson territory as he was there when Lucy was discovered and published the findings. Where Wong may not have an immediate connection to Wolpoff, aside from earning her Bachelor’s from the department Wolpoff teaches in, she does have a clear one with Johanson. She was a coauthor with Donald Johanson on a book published this year, Lucy’s Legacy.

As you may know, there’s also sour grapes shared shared between Johanson and White. I won’t get into those details… But its clearly out there and is exemplified by a passage in Lucy’s Legacy,

“Tim is a very exacting scientist who is not about to be pressured into saying more about ramidus until he is good and ready. But his unwillingness to share more information about the fossils – not to mention access to the remains themselves – in a much more timely way has drawn criticism. (So secretive are he and his team about the fossil that it has been referred to as the Manhattan Project of paleoanthropology.) In fact, spurred in part by Tim’s actions, some researchers have even proposed that funding agencies such as the National Science Foundation establish a limitation on how long the discoverer of a fossil has exclusive access to that material before having to share it with other investigators.” p. 155-156 Lucy’s Legacy

There’s no way to know if Johanson or Wong wrote this particular passage but they both share authorship and royalities of the book and ultimately agree on the points raised in the text.

This is a clear conflict of interest for Scientific American and their anthropological editor, Kate Wong. As an editor of Scientific American, for Wong to be an author of a book which conveys the same criticisms as published under anonymity in their magazine and on their website, shows that she exploited her professional capacity for personal benefit.

In addition to egregious political move by Scientific American, the piece is ignorant of the whole process involved in finding, cleaning, documenting a fossil. Fossils don’t come out of the ground perfect. Believe me, I know. Some of the time these findings are as delicate as a ball of dust and require a great deal of care to preserve them during which time it is the primary investigator/discoverer’s responsibility and privilege.  I’ve actually discussed this before, very thoroughly in this comment thread.

For the editors and other supporters to suggest there should be a limit to how long it takes to prepare a fossil show how they really have no idea to what it takes to curate a fossil. There’s no way to put a time limit on this process. Aside from a select few, most field scientists are professors at universities. Again, as I’ve said before, their time in the field is limited, several months a year, of which time is split between finding new fossils and curating old ones. Field scientists, like White, can’t leave their teaching positions at places like UC Berkeley and dedicate years to preparing the specimen. They do as much as they can and they do it with quality. The Middle Awash, White’s stomping ground, has an impressive record of impactful, frequent fossil discoveries and publications which can’t really be said for Wolpoff and Johanson.

You may consider this a defense of White. I admit this is. This was a shameless jab at White and a despicable, cowardly, and haphazard move by Scientific American. Science is not about quantity. I shouldn’t have to tell freaking Scientific American that. Science is about quality. Editorials like this don’t advance the field. They completely ignore that science is a process and not a product. In doing so they damage the discipline.

One last thing… To the editors of Scientific American, grow some balls next time you wanna put out crap like this and publish your full names along side your criticism. Stand behind your words.

Kambiz here. I’m about to start my second term of medical school, which is both exciting and nerve racking. In my summer readings, I came across a medical and anthropological tidbit today that caught my attention: redheads have a lower tolerance for pain. I didn’t know that.  Did you?

Skin pigmentation is one of my favorite topics. We know from previous posts that the melanocortin-1 receptor gene or MC1R affects melanin production and ultimately skin and hair phenotypes. Redheads carry a variant of MC1R which produces a different pigment, called pheomelanin, resulting in freckles, fair skin and ginger hair.

How MC1R receptors affect pain is another story though, one that is not well understood. Aside from the skin MC1R is also expressed in the brain. It could be possible that the redhead allelic variant of the MC1R receptors don’t quite receive the signal transduction of pain reception in the same manner as those with the wildtype receptor. I don’t think I’m gonna become an anthesthesiologist but as someone interested in human genetic variation it is good to acknowledge some phenotypes affect how medicine is delivered. ;-)

Anyways, I don’t have much else to add to this other than to share some interesting information and to let you all know I’m alive but will be crawling under a rock again. Till next time.