Anthropology.net

This announcement is a call for papers for the 16th International Union of Anthropological and Ethnological Sciences (IUAES) in Kunming, Yunnan, China on 15-23th July 2008. The session will be on Anthropology and Islam with three panels focusing on:

• Visual Anthropology in Muslim Societies: Problematics and Methodologies
• Death and Dying in Muslim Societies
• Space and Gender in Muslim Ritual and Ceremonies

We invite the submission of expressions of interest for these three panels which will form the Anthropology and Islam session at the 16th International Union of Anthropological and Ethnological Sciences (IUAES) on Humanity, Development and Cultural Diversity.

Please visit this link for more information on proposing a paper for inclusion in one of these three panels. If you want even more information please contact me directly. I’m session’s chair, Dr. P. Khosronejad, Junior Research Fellow at The Middle East Centre in St.Antony’s College, University of Oxford. 

I’ve covered copy number variations in the past, and the post I put up this morning is kinda along the same lines as the following paper I will introduce. But, in a nutshell, this one is a comparison of copy number variation or CNVs in primate genomes.

CNV is a term used in genomic studies to describe the amount of copies of a particular gene in a particular genotype. Copy number variations are a type of polymorphism that can come about from transposons and restructuring of genomes due to Alu elements. Sometimes changes in CNVs imply that genes have been positively or negatively selected for.

In the new report, soon to be available in Genome Research, the results of a large-scale, genome-wide study to investigate gene copy number differences among ten primate species, including humans have been published. The study, “Gene copy number variation spanning 60 million years of human and primate evolution,” will be online tomorrow and is the most comprehensive research on gene copy number variation across human and non-human primate species so far. It provides an overview of genes and gene families that have undergone major copy number expansions and contractions in different primate lineages spanning approximately 60 million years of evolutionary time.

Dr. James Sikela and team used microarrays with over 24,000 human genes to screen and compare genomic hybridization. In other words, they compared DNA samples from humans to those of nine other primate species: chimpanzee, gorilla, bonobo, orangutan, gibbon, macaque, baboon, marmoset, and lemur in oder to identify specific genes and gene families that, through evolutionary time, have undergone lineage-specific copy number gains and losses.

The authors of the report suggest that,

“many of the genes identified are likely to be important to lineage-specific traits found in humans and in the other primate lineages surveyed.”

Several gene families that exhibited striking lineage-specific differences were highlighted. In particular, the human lineage-specific copy number expansion of a gene called AQP7, a gene that plays a role in transporting water and glycorol across membranes, was pointed out because it could explain why humans have evolved the capacity for endurance running. It may facilitate the mobilization of energy stores during long periods of intense exercise as well as playing a role in dissipating excess heat through sweating. I’ll have more on this tomorrow, when I get access to the paper but the other findings included dramatic gene copy number differences potentially associated with cognition, reproduction, immune function, and susceptibility to genetic disease. Read the rest of this entry »

Yann has found some interesting papers in the last day or so. One paper he stumbled upon researches the heritable variation of Angiotensin Converting Enzyme (ACE) in humans and baboons. It is titled, Parallel effects of genetic variation in ACE activity in baboons and humans.” ACE is a homeostatic regulator protein, and like other physiological phenotypes, it varies a lot in humans. Proteins that vary a lot are important to research because they help explain how we see so much variation in human populations.

The variation in ACE is attributed with an Alu insertion-deletion polymorphism in the ACE gene. Since I don’t know if you have heard of Alu elements, I’ll explain to you what I know of them. Much of the human genome, and as we are now finding out much of primate genomes, have a lot of transposable elements in them. Transposable elements are segments of DNA that jump around, copy, and rearrange themselves. This genetic versatility facilitates lots of diversity, variation, and potential for selective processes.

Alu elements are classified as a type of transposon where copy is made of RNA, not DNA. This is more specifically called a retrotransposon. Short interspersed elements (SINEs) are about ~300 nucleotides in length and are an even more specific type of retrotransposon . The most abundant type of SINE are Alus. More than 1 million Alus are found in the human genome and make up about 10% of the genome. I found a paper announcing the creation of a database specific to Alu elements in the human genome, but the link to the database doesn’t seem to work. Oh well.

If you want to read more about Alus check out this review article but for your sanity’s sake I’ll wrap up the review of Alu elements… Because Alus are more or less mobile they are important because they affect gene structures, protein sequences, splicing motifs and expression patterns.

You’re probably wondering what was concluded from the comparison of the ACE in humans and baboons? From the abstract,

“We identified a similar Alu insertion-deletion polymorphism in the baboon ACE homologue and measured its frequency in a wild population and a captive population of baboons. We also analyzed the contribution of ACE genotype at this indel to variation in serum ACE activity in the captive population. When conditioned on weight, a known factor affecting ACE activity in humans, age and ACE genotype both accounted for variance in ACE activity; in particular, we identified a significant nonadditive interaction between age and genotype…. These results demonstrate an interesting parallel between the genetic architecture underlying ACE variation in humans and baboons, suggesting that further attention should be paid in humans to the relationship between ACE genetic variation and aging.”

Go figure, ACE, a homeostatic regulator protein, has something to do with aging. And the variation, the amount of Alu element restructuring of ACE has a correlation to how long or short humans and baboons live. Interesting.

More fun reading on the subject:

• Alu Insertion Polymorphisms for the Study of Human Genomic Diversity
• Recently Integrated Alu Elements and Human Genomic Diversity

There has been brief mention these past few days of two human footprints that have been found preserved in sandstone, by a team of archaeologists under the supervision of Dr. Ahmad Hassan Dani, of Taxila Institute of Asian Civilisations at the Quaid-i-Azam University, in Islamabad. As we see…

A footprint of 1 feet is in complete and well preserved form while another is broken from the finger side which is also of the same size in comparative manner. The notable marks of the feet are the clear veins and opposite folded appearance.

“A huge stone on the top of the hill is the secure home of these prints since about over one million years ago,” says A.K. Azad, an archaeologist and head of the project.

Further research may give more clues of the foot marks through anthropological and geophysical methods, he observed.

The recent discovery is the continuity of the Indusian Research Cell’s earlier research about human evolution which previously revealed a fossilised upper jaw from the site of Dhudhumber, foot and hand prints from Attock and Palaeolithic cave from Margalla Hill.

If the dates are correct, it would mean the most likely owner of the feet that left the prints was Homo erectus, an archaic species of human which has come to be seen as the first truly pioneering hominid which spread itself far and wide across the Old World – although there is still debate as to whether all Homo erectus evolved in Africa, and populated the outside world in an ongoing series of migration events, or whether the species evolved separately in both Africa and Asia.

At 1 million years old, these Homo erectus footprints are significantly younger than the 1.7m bp Dmanisi fossils, which themselves are considerably younger than the purported 2.25m bp stone tools found at the site of Renzidong in China. However, even these early hominid sites may have been eclipsed by finds announced in 2000, by M.P.Singh, described in this abstract…

The Siwalik Hills have yielded what is perhaps the world’s most ancient early hominid. In December 1992 I discovered a hominid mandibular ramus and a hominid femur in association with stone tools in the Tatrot Formation of the upper Siwalik. The discovery was made from the Tatrot Formation exposed at Khetpurali Village in Haryana, North India. The teeth are bunodont, having a lingually inclined wear plane. The P3 is molariform and single rooted.

The femur is platymeric and has medullary stenosis. The stone tools are chopper types. Magnetostratigraphic dating of the Tatrot Formation ranges from 2.47 Myr at the top to 5.44 Myr at the base. The hominid — yielding bed is dated at 3.40 Myr — Middle Pliocene. The palaeoecology of the Tatrot Formation suggests open savannah. The discovery will cast new light on the origin and migration of the early hominids, and hopefully will contribute to a solution of the 100-year-old dispute about the African or Asian origin of humans.

The full paper is behind a paywall, and I’m not sure what developments, if any, have occurred since then – in the meantime, it appears that further work will be undertaken by others, or extensions to the project “Post-earthquake Explorations of Human Remains in Margalla Hills”, which was set up in the wake of the disastrous earthquake at Muzaffarabad in Kashmir, which hit the region back in October 2005. (TJ)

see also: New Dimensions Of Ancient Heritage Explored In Soan Valley

Although I should have posted this earlier, Afarensis is hosting the next Four Stone Hearth, so this is a reminder to ask anyone who’s interested in submitting material of their own, to send it along in time for Wednesday; alternatively, if you see the work of someone else that you consider would be a worthy addition, please feel free to send that in too. Although it’s good to have new material for each carnival, not everyone always has the time to just sit down and rattle off a quick essay, so if you have, or see something suitable that was written a while back, please consider sending material of that ilk too.

image of Afar Triangle from here – interesting to think that a region which may have given birth to some of the earliest known hominids, is now slated to give birth to a new ocean, as the African and Arabian continental plates begin to drift apart – der Spiegel has more. (TJ)

I was wrong to say today was a slow day in anthropology related news, because I just found a brand new hot off the press human brain evolution paper published in the American Journal of Physical Anthropology. I found the paper through Razib’s Homo amygdala post over at his blog Gene Expression.

My thesis research is in neuroscience, so this sort of publication is exactly what I like. And if it weren’t for Razib, this paper woulda passed under my radar. To say that I’m excited is an understatement, especially because this paper relates and compares brain evolution and social cognition abilities in hominoids.

As the title of the paper, “A comparative volumetric analysis of the amygdaloid complex and basolateral division in the human and ape brain,” implies, the study was founded on comparative analysis of the amygdala from 12 ape and human specimens. Why the amygdala? Well, the amygdala is a region of the brain that functions in the formation and storage of memories associated with emotional events. It is essential in helping us read the emotions of others, and perhaps facilitated our ability to form relationships and live and work in groups.

I’m gonna give you a really brief run down on the neurobiology of the the amygdala because without it, the findings that I will summarize will be mostly mumbo jumbo. First and foremost, the amygdala the image to your right shows you where the amygdala is found in the human brain. The amygdala is made up of about twelve sub-regions. To the best of my knowledge, the exact functions of each sub-region have not yet been pinpointed. But what is known is that many of them maintain connections that participate in fear and emtional reactions actively.

The primary function of one of the regions the paper talks about, the lateral nucleus, has been identified. It is the gateway of signals and information into the amygdala. Or in other words, it is through the lateral nucleus that the amygdala receives information from the outside world.

Okay with that hash job in brain anatomy and some of the intricacies of the amygdala, I think we should move to the paper. Katerina Semendeferi lead a group that measured area of the 12 amygdalas and low and behold found that the human amygdala was much larger than those of the other apes. That’s not too surprising. Our brains are the largest of the group they compared, so I would expect regions within the brain, like the amygdala to be proportionally larger as well.

Curiously, though, the lateral nucleus occupied a bigger portion of the amygdala than the other sub-regions in humans than the other primates compared. On top of having a larger lateral nucleus, more incoming connections from the temporal lobes, were noted in the human brain as well.

The temporal lobes are home to some critical social senses. The primary auditory cortex is located in the temporal lobe, and so the temporal lobes specialize in auditory processing. They are also heavily involved in speech and vision processing. This implies that as humans, the larger lateral nucleus in the human amygdala allowed more auditory and vision information to be processed. Semendeferi and team took this observation and,

“concluded that the amygdala’s lateral nucleus has enlarged relative to the rest of the structure since the human line split from the apes, and that this enlargement might reflect the “social pressures” of living in large groups. For example, Semendeferi and her colleagues note that the orangutan, which has a relatively smaller amygdala and lateral nucleus than those of the other species, is [more] solitary.”

This is interesting research to me. In a ScienceNOW news article, James Rilling suggested that the hypothesis that the prominence of the lateral nucleus is related to social cognition, is ‘reasonable’ if the sample size is extended.

“The next step, he adds, would be to use brain-imaging techniques to see whether the human lateral nucleus really does make more connections to the temporal lobe than that of other apes.”

Which, I agree. If we see the temporal lobe deliver more information or be more actively involved with the lateral nucleus of the amygdala, then that would be a solid case. I also wonder how the innervations of the temporal lobe with the lateral nucleus of the amygdala of autistic people, look and function? What I’m saying is that why not extend the comparative analysis to autistic humans and see how they compare to other humans as well as other apes. We know their amygdala’s have fewer nerve cells and their behaviors are characterized by decreased social interaction and an inability to understanding the feelings of others… but what about their lateral nucleus?

It is a rather slow anthropology news day, but the plight of the Hadza is still on my mind. So, what better way to fill the gap than to share with you some awesome photos of the Hadza found on Flickr?

Science has just put out a news piece updating us on new research about the Nasca lines, which are located in the Peruvian Desert. It is titled, “Digging Into a Desert Mystery.”

I consider the Nasca, or Nazca, a mysterious culture, especially after a headless man was found and reported on in June. The Nasca lines are no less enigmatic.

So other than being difficult to explain, what are the Nasca lines? Well, Nasca lines are designs, images, and modifications made to the land. The purpose of the lines are largely unknown but very fascinating. They were scratched on the surface of the ground somewhere between 500 B.C. and A.D. 700 (there are actually several different estimates on the age range, for your information) and they were declared an Archaeological World Heritage Site by UNESCO in 1994.

Some of the designs are of giant animals, like a 180m-long lizard, a 90m-long monkey with an extravagantly curled tail or a condor with a 130m wingspan. Most of the lines are simple but perfect triangles, rectangles or straight lines running for several kilometers across the desert, to be best observed by plane. In total the designs stretch over 53 miles or 80 kilometers!

You can either fire up Google Earth, type in ‘Nazca lines’, to check them out or you can click this Google Maps link to see satellite imagery of the area. No matter the method you chose, you will see the massive lines etched out pretty clearly.

But back to the research… to be honest, since my university for some odd reason doesn’t have access to Science, I have no idea what they have published other than it has something to do with,

“A systematic campaign of aerial photography and archaeological digs has shed light on the enigmatic Nasca lines, massive designs created centuries ago on the desert floors of Peru.”

I’m thinking the piece is just an update on a more thorough effort to document and curate the lines. But that’s all an educated guess from the one sentence teaser we get. Does anyone mind sending me the article? I’m curious to know what more has been discovered.

I wanted to really quickly give kudos to Afarensis, who dutifully ripped apart a dumb question that a creationist asked in regards to recent research on bipedalism. If you come from the camp that thinks there isn’t such a thing a stupid question… then I’m sorry to rain on your parade. There is such a thing as a stupid question and the following is a prime example of idiocy in its purest form. Here’s question,

“If upright walking is so energetically favorable, why do apes still “knuckle-walk”?”

Questions like this have been part of the creationist canon for some time. They use it, albeit ignorantly, because they think it is a valid attack point and weakens evolution. Unfortunately for them, as Afarensis points out, there’s a lot of flaws in thinking that way.

I want to take the time to answer this question and also add/clarify that the recent research I reviewed, on bipedalism energetics, simply shows that bipedalism is more energetically favorable for us. And that’s because our bodies are adapted to this form of locomotion. I’ll provide a lot of comparative anatomy to argue this point.  For example, the vertebrae in our backs are organized in a way to distribute the weight down to our pelvis which has a very different structure compared to other great apes. Our legs are longer and the bones are more robust than our arms because they bear more weight than the arms. The knee joint and the foot also exhibit differences that beneficial to bipedal walking.

Bipedalism is not a favorable form of locomotion for chimpanzees because their bodies are adapted primarily for terrestrial quadrupedal knuckle walking. Compared to humans, their arms are longer than their legs, their backs aren’t as specialized in weight distribution, and their hands, rather than their feet, exhibit robusticity because they bear lots of weight and force.

Now it is not all about the differences in bones and the skeletons. The illustration to your right, from a American Museum of Natural History webpage, compares some the soft tissue involved in the biomechanic differences between chimps and humans.  In the top left of the illustration, you see drawings of the three semicircular canals located in the inner ear, the primary organs for maintaining balance. In humans, two of the three canals are specialized to  stabilize the head. Also, in humans, there are fewer muscle connections between the head and the shoulders when compared to the chimpanzee. That’s cause quadruped chimps have to fight gravity in order to hold their heads up while walking on fours. Our head just sits on our necks.

In contrast to the head and neck, humans have more connections between the gluteus maximus muscle in the butt and the hip than chimpanzees do, which stabilizes the femur into the pelvis and helps keeps the trunk and leg moving together. Both the Achilles tendon of the heel and the tendon of the arch of the foot are much smaller in chimpanzees than they are in humans; in a running person they act like springs, absorbing and releasing energy.

So to ask, “why do apes still knuckle walk?” is straight up stupid. They don’t walk upright because it hurts, it is draining and inefficient.

You maybe thinking, “Hey, I’ve been to the zoo! I saw the YouTube video clip of the chimp and dog you shared with us. I’ve seen chimps run around on twos!” Chimps sometimes walk in short bipedal bursts. I’m not saying they don’t. But as the paper calculated, when they do walk bipedally, they experience more tension on their bones and joints than we do. That added tension and force costs more energy for chimps to walk bipedally because they aren’t adpated for it.

I imagine a similar but opposite conclusion can be made if the energetics of human knuckle-walking quadrupedalism is calculated and compared to that of a chimp. Try walking on all fours and not look like a idiot at the same time. You’ll soon experience tension on your bones and joints. After maybe about a dozen yards or so, fatigue will overcome your ability to keep up this form of locomotion. Why? Because our bodies are not adapted for and haven’t been selected for quadrupedal locomotion.

Any one, creationist or not, who thinks that bipedalism is a better form of locomotion should revise their train of thought. Apes still knuckle-walk because that’s part of the ecological niche they occupy. We humans walk on our two legs because that’s part of the ecological niche we occupy. Natural selection, or some other evolutionary force, continues to select for each of us to move about that way. Their bodies are damn efficient at knuckle-walking. Our bodies are damn efficient at bipedal walking. Simple as that.

Hot on the heels of the recent discovery of a 1.2 million (?) year-old tooth at Atapuerca, comes this news of skull fragments dating to 500,000 bp, and found in the Sima de los Huesos, the cave of bones’, better known for the finds of fossilised remains of around 30 individuals, at the bottom of a deep shaft, and dating to about 300,000 bp or earlier. This latest find is of cranial material belonging to what is believed to have been an adolescent female. The linked articles are in Spanish, and although I can translate some of it, my initial reading of the story failed to pick up the salient points, and it was only when someone at Anthro-L thoughtfully corrected my errors that I realised that this was a couple of new finds, rather than referring to the earlier discovery of the tooth a week or so ago. Here’s what was relayed to me at Anthro-L…

To quote (in translation): “two parietal fragments and one frontal have been identified, all [3] of great size….” Two tiny middle ear bones have also been found with the skull fragments.

I then found that Google Translate was able to offer something in the way of an interpretation, and from here on in, I’ve referred to their version of this story. We hear from Luis Arsuaga, who appears to be saying that this is an important find because there are very few remains from 500k bp, and it constitutes more material of this type than has been found in Europe over the last 30 years *(specifically, the frontal elements found here, rather than in the past when only material from the main cranial vault had been found – I think). He also believes that the ear bones will cast light on the erstwhile owners’ ability to speak – there is still much debate as to when archaic humans began speaking, although it’s my guess that by this time of 500k bp, people had probably been speaking for hundreds of thousands of years.

There is mention of a lower premolar tooth found at Sima del Elefante, dating to 800,000 bp, which seems to coincide with the level TD-6, at which the other 800,000 year-old remains were found in Gran Dolina, another component of the Atapuerca site. The named species here is Homo antecessor, and they seem to be saying they were the earliest hominids in Europe, although there have been suggestions from the south at Orce, and Cueva de Victoria, dating to possibly 1.3 million years and more, which have been variously assumed to be either Homo habilis or Homo erectus.

The final word from the site appears to imply that the recently discovered Homo antecessor fragments dating to 800,000 bp in Gran Dolina adds evidence to earlier finds that cannibalism was practised there – over a period of hundreds of years, rather than as a one-off event as previously speculated. The victims appear to have been young, and there is mention that incoming outsiders may have fallen victim to this – though there is an implication that there was a cultural rather than merely utilitarian intention at work here – please see this article from 2006

The most recent finds were made right at the end of the current season of excavations, which over the years, has proved a curiously consistent stage of important discoveries. The teeth will be properly written up in the early months of next year, no word of when the skull fragments will be properly analysed, but I imagine that would be sooner rather than later.

There is mention that research at Atapuerca has in the past been restricted to one month a year, but there are hopes that this will increase to 3 or 4 months – which judging by the rate they’re pulling remains from the ground, sounds like a good idea. They make reference to Neanderthals, by describing them as the only archaic species of (European) archaic Homo not to have been found at Atapuerca.

There is also a hint from Eudald Carbonell that Atapuerca may be evidence for Europe as potentially having been a region, along with Africa and Asia, that gave birth to its own separate species of archaic Homo – a somewhat radical view, and I’ll try and track down a paper on the subject, if indeed he has written one.

This post may be subject to yet further amendments, but hopefully most of my earlier errors have now been corrected – apologies for the rather garbled nature of this post, it’s been one of those days.

n.b. I can’t get the image to display properly, so for the time being please access the linked story at Diario de Mallorca, where there is an expandable picture of the cranial fragments.

Google translation here or try: Google Translate beta

(via Anthro-L – thanks to Weyert de Boer for the heads-up, and Phil Young for the translation)