Anthropology.net

Razib has chimed in on the latest piece of research to come from John Lukacs, “Fertility and Agriculture Accentuate Sex Differences in Dental Caries Rates,” published in Current Anthropology. Throughout time, women have had more cavities on average than men. I’ve explained how cavities are formed in a previous post.  Diet change and sexual division of labor have been suggested to be the dominant forces at play. With the Neolithic revolution, the human diet and lifestyle was dramatically revamped. With steady food sources, people reproduced faster and populations boomed.

Lukacs did a comprehensive review of records of the frequencies of dental cavities in both prehistoric and living human populations in his paper. His sample included teeth from people of Euro-American ancestry, and from Africa, teeth from Guinea-Bissau, Madagascar, and Niger… from Asia, he covered China and Taiwanese aboriginals.

He concluded that the increased sedentary lifestyle and fertility increased the demands on the female reproductive system, which in turn intensified the negative impacts of dietary change on oral health. of women He attributes the increased rates of dental caries in females to three factors:

• Female sex hormones, like estrogen, significantly impact cavity formation. Estrogen is produced by the placenta throughout a pregnancy and the levels increase steadily until birth.
• Females produce less saliva than men. Saliva has two important components, enzymes like amylase, that begin break down of complex sugars. If these sugars aren’t broken down, microbes in the mouth consume them and as a biproduct release acids that break down the enamel of the tooth. Saliva also has another component, antibodies and phagocytes that attack the very microbes that cause cavities.
• Women crave high-energy, sweet foods during the third trimester which we all know are promotes cavities and dental decay.

So ultimately female physiology combined with the the changes in diet and increased feritlity are the reasons why women have more cavities than men. Razib mentions that with increased fertility comes a reciprocal increase infant mortality, especially because the agricultural revolution increased communicable diseases. He concludes that hunter-gatherer infants are far more likely to reach reproductive age than infants of an agriculturalist.

But I disagree. Despite the recent popularity of the paleo-diet, the real hunter gatherer lifestyle is not easy. Many hunter gatherer societies have erratic sources of nutrition, very few have regular caloric intakes. John Hawks explained that among hunter gatherers, like the Hiwi, only 43% of the adults were expected to see the age of 30. Furthermore, many hunter gatherer cultures also have food taboos which dictate the diets of females. For example, Australian aboriginal societies restrict protein and fat foods for pregnant and lactating women. Similar traditions exist in Africa too. In Athapaskan societies, females at menarche cannot eat fresh meat.

Women who do not consume many calories, reach menarche at an older age and become amenorrheic — irregularly menstruate. If and when they do have a child, they are often of low birth weight, and the child has a higher risk of dying because they have little to no fat reserves. They consume inadequate amounts of nutrition since the mothers cannot make insufficient amounts of milk. All of which influences birth spacing significantly.

Despite the increased probability of cavities, the Neolithic revolution has generally been a good thing for women and children.

John R. Lukacs (2008). Fertility and Agriculture Accentuate Sex Differences in Dental Caries Rates Current Anthropology, 49 (5), 901-914 DOI: 10.1086/592111

Okay, I got some really cool archaeology news to share with you. In fact it is so cool that I’m staying up to write up my review. Before I get into it, let me first introduce some relative background you’ll need to understand.

One of the most important predecessors to the Inca Empire were the Tiwanaku, a pre-Columbian culture that expanded from a home base on the south eastern edge of Lake Titicac, Bolivia to what is now southern Peru and northern Chile. The expansion happened between 1,500 years ago to 1,000 years ago and is commonly referred to as the Middle Horizon of Andean prehistory.

The Tiwanaku perfected a type of agriculture which raised crops from the ground. Lowered canals innervated the mound-like crops, and during the day, the crops absorbed water and canals absorbed solar radiation. During chilly nights, the heat radiated into the soil, preventing crops from freezing. The warmed canals also served a secondary function: providing a water source to farm edible fish.

Aside from their unique achievements in agriculture, the Tiwanaku also had an equally curious architectural style, employing massive ashlar blocks sometimes as heavy as 130 tons quarried 40km away. They built temples and platforms as large as 200 meters on each side and 15 meters tall. According to some hand-me-down stories, myths passed down to the Incas and then to the Spanish, these buildings served as spiritual centers. Fittingly, structures like the Gateway of the Sun have representations of their main deity, Viracocha. Other statues represent other deities, sometimes even abstract representations of a calendar and religious purposes.

An Example of a Tiwanakuan Snuff Kit

Tiwanaku burials continue this spiritual motif. Many mummies and skeletons from this culture also include tablets and snuff kits documenting the use of psychoactive drugs perhaps in a spiritual afterlife ritual or shamanistic tradition. In fact an archaeologist reported 614 snuffing kits recovered from an excavation, which suggests that the Tiwanaku were possibly using hallucinogenic materials. Previous chemical analysis of the kits indicated that they once held Vilca  (Anadenanthera colubrina), a plant rich in hallucinogenic tryptaminic alkaloids. Ethnographers have documented consumption of Vilca or hatáj by Wichi shamans. CAT scans of Tiwanakuan skulls have shown signs of chronic perinasal damage in some cases, likely caused by frequent sniffing of Anadenanthera. But we haven’t, as of yet, proven that the Tiwanaku consumed these drugs.

And here’s where a new paper in the Journal of Archaeological Science comes thru. The paper, “Identification of psychoactive alkaloids in ancient Andean human hair by Gas Chromatography/Mass Spectrometry ,” involves an analysis of the chemical composition of hairs from 32 mummies from northern Chile, dating to the Tiwanakuan expansion. The hairs were removed then cleaned and alkaloids were extracted from them. The alkaloids were loaded in a gas chromatographer, a device that separates molecules into compounds based upon how they move about through a stationary phase. Every compound has a specific retention time in the stationary phase, which ultimately is detected by a scaled down mass spectrometer. The mass spec gives a mass to charge ratio for every compound and this is all assembled to build the unique chemical fingerprint of a molecule.

The authors’ methodology seems sound. They duplicated some trials if they had extra material, even did triplicates when they had a lot more hair lying around. They also calculated the lowest detectable amount of alkaloid, just to determine the limits of accuracy. And for one more precautionary move, they also looked at modern day samples as well, to see if there’s something in the air or water that’s being inadvertently absorbed.

They specifically looked to find fingerprints of harmine and 5-methoxy-N,N-dimethyltryptamine. I don’t know what 5-methoxy-N,N-dimethyltryptamine does. It is found in Anadenanthera colubrina, so I assume it is a psychoactive drug… If any pharmacologists, physicians, chemists, neurologists, etc. out there know its affects please let me know in the comments below. But I do know what harmine does. It ultimately inhibits the break down of neurotransmitters, like serotonin and dopamine, giving the consumer more prolonged effects of abundant neurostimulus.

The results suggest that none of the mummies tested positive for 5-methoxy-N,N-dimethyltryptamine alkaloid, which is highly controversial considering lots of snuffing kits test positive for this chemical. The results also showed that two of the mummies tested positive for harmine. The first harmine using individual was buried with drug paraphernalia, but did not have lesions. In fact he has a snuffing tablet, one four points hat and the remainders of another one, and several pan pipes. The hat indicates the individual was of significant social prestige. CAT scans of his skull show that he had sclerotic lesion in the perinasal area — perhaps a chronic sniffer. The other individual was a 1 year old infant, buried with also with tablet and a four points Tiwanaku hat. It is highly unlikely that we had a 1 year old drug addict — but perhaps drug consumption was part of the ceremonial processes either during the life of this child or immediately after?

Since only 2 of 32 individuals showed evidence of drug usage, the authors were cautious to say drug consumption was rampant, but they did provide direct and conclusive evidence of consumption of psychoactive substances. Furthermore, the Banisteriopsis vine is the only South American species studied that contains harmine. The vine is found only in Amazon basin, far away from the Azapa valley indicating the possibility of a vast trade network of Tiwanaku. Ultimately, I commend the authors for successfully providing the first direct archaeological evidence for the consumption of hallucinogenic herbs.

Ogalde, J.P., Arriaza, B.T., Soto, E.C. Identification of psychoactive alkaloids in ancient Andean human hair by Gas Chromatography/Mass Spectrometry, Journal of Archaeological Science (2008), DOI: 10.1016/j.jas.2008.09.036.

If you look at the time stamp of both Bora‘s and Greg Laden‘s posts, you’d notice that they just broke the embargo on a new study of a prehistoric case of tuberculosis that was supposed to go live at 5pm PST, 8pm EST. Now that the news is out, albeit slightly earlier than expected, I figure I should also cover it. The press release touts that the human remains from a site called Atlit-Yam in Israel have provided genetic evidence for the earliest known cases of tuberculosis, dated at 9,000 years old.

Atlit-Yam, Israel

Atlit-Yam is a site currently submerged 8 to 12 meters below sea level in the North Bay of Atlit. The site is about 10 kilometers south of Haifa. Previous researchers have radiocarbon dated the site to be 9,250 to 8,160 years old. The site has yielded both floral and faunal remains along with tools. The floral remains and the faunal remains indicate that these people already made the transition from hunter gatherer subsistence to a fully Neolithic lifestyle.

Human remains were also recovered from the site, and some show characteristic bone lesions that are signs of tuberculosis, specifically the remains of a 25 year old woman buried with an infant. The age of the woman was estimated based on dental attrition, epiphyseal ring ankylosis and the symphysis of the pubis, which are all pretty solid markers. The bones were preserved in a muddy dark clay substance, an anaerobic condition which is very conducive for DNA preservation. Even though other elements have tuberculosis caused lesions, the researchers specifically analyzed the ribs and arm bones of the female adult and long bones of the infant.

Paleopathological lesions on Neolithic infant bones.

Because of the excellent conditions for DNA preservation, the authors moved ahead with two molecular techniques to determine if tuberculosis was the causative agent of the lesions. First they deployed a PCR experiment, specifically designing a primer set to the fish out Mycobacterium tuberculosis sequences. Secondly, they utilized a reverse phase high performance liquid chromatography (HPLC) method that tried to isolate mycobacterial cell wall mycolic acids from the sample.

The PCR yielded positive results with the multi-copy IS6110 & IS1081 fragments, obtained from the rib of the woman and infant long bone. The fragments were confirmed to be valid by sequencing. These fragments are restriction fragment length polymorphisms and are commonly used as definitive signatures of Mycobacterium tuberculosis. The authors compared their PCR fragment sequences to Genbank and also reported that the sequences are identical to those in the NCBI database for M. tuberculosis.

The HPLC also provided evidence that there are mycobacterial cell wall molecules present in the samples. The woman had the highest amount per mg of bone, at 20.14 pg, while the infant had a smaller amount at 0.12 pg/mg. Nonetheless, both lines of evidence along with the visual lesions show that at least two of the people of Atlit-Yam had a tuberculosis problem.

As I mentioned, it seems that the press is going to love the ‘earliest evidence of TB’ sound bit. But it’s not particularly true because, John Kappelman announced the discovery of tuberculosis in a 500,000 year old Homo erectus cranial fragment last yet. I have my doubts about the H. erectus diagnosis though. The authors also did review other paleo-tuberculosis cases such as the 17,000 year old bison and the 4,000 year old Egyptian human bone and soft tissue sample. Either way, this is the earliest report of the disease in humans that has been confirmed by molecular means.

One last thing, Atlit-Yam is among the very few Pre-Pottery Neolithic sites where domesticated cattle have been found. Tuberculosis in humans was thought to have a zoonotic origin, perhaps transmitted to humans from domesticated cattle during the Neolithic revolution. But that theory has been on the rocks, and these individuals were clearly infected with Mycobacterium tuberculosis, not Mycobacterium bovi, which infects cattle. Could the cattle have caused the tuberculosis in these two individuals? What do you think?

Israel Hershkovitz, Helen D. Donoghue, David E. Minnikin, Gurdyal S. Besra, Oona Y-C. Lee, Angela M. Gernaey, Ehud Galili, Vered Eshed, Charles L. Greenblatt, Eshetu Lemma, Gila Kahila Bar-Gal, Mark Spigelman, Niyaz Ahmed (2008). Detection and Molecular Characterization of 9000-Year-Old Mycobacterium tuberculosis from a Neolithic Settlement in the Eastern Mediterranean PLoS ONE, 3 (10) DOI: 10.1371/journal.pone.0003426

I remember reading a short announcement in 2003 about the discovery of 385,000–325,000 years old human-like footprints near the Roccamonfina volcanoes in southern Italy. We haven’t found many paleo-footprints, so any discovery is welcomed with excitement and of course with controversy. Some of the most notable paleo-footprints are the 3.5 million year old prints from the Laetoli ash bed in Tanzania (which are in danger of being destroyed), the Pleistocene footprints from Langebaan, South Africa and another set from the same era from Willandra Lakes, Australia. There’s also the highly curious 40,000 year old Toloquilla footprints in Mexico.

Photos of the Devil's Footprints from Roccamonfina Volcano (Source: 10.1038/422133a)

The three sets of prints from Roccamonfina show that these individuals were fully bipedal and were navigating a steep descent. The tracks have some sharp hairpin turns, indicating at times they were negotiating some precarious moments. There’s even evidence of slipping, an occasional hand print shows up from time to time, suggesting someone wiped out a couple times.

The authors also measured the dimensions of the tracks and estimated that the individuals who made them were no taller than 1.5 meters in height, or 4 feet 11 inches. Again, they were fully bipedal but didn’t have a completely modern human gait. The authors were careful and didn’t get into a discussion about exactly which archaic Homo species made these tracks. At this time in Europe Homo heidelbergensis is thought to be the dominant species. The authors were also cautious and warned that the dating of the volcanic tuffs that the trackways were made on are provisional and preliminary.

I haven’t read anything about the footprints until yesterday, when I saw that Dienekes shared a citation to this new paper, “Oldest human footprints dated by Ar/Ar.” The authors of the new paper criticize that the previous authors relied on an old and imprecise K–Ar date. They instead decided to do a detailed ⁴⁰Ar/³⁹Ar dating from a sample collected directly from the footprint-bearing layer (about 5 meters away, actually). A whole range of dates were ultimately calculated, from 332,000 ± 5,000 to 403,000 ± 5,000 years ago, but a tightly grouped peak of dates clustered around 340–348,000 years ago. The authors calculated the best fit a Gaussian distribution centered at 344.5 ± 5,600 years ago.

With this slightly more refined date, we now know that the footprints were made awfully close to the Climatic Termination IV, a time at which the global ecosystem was making transition between a glacial maximum and the sudden establishment of warmer conditions…. Providing us a window into several minutes of archaic human activity during a shift in ecological and paleoclimatic conditions of the Middle Pleistocene.

Paolo Mietto, Marco Avanzini, Giuseppe Rolandi (2003). Palaeontology: Human footprints in Pleistocene volcanic ash Nature, 422 (6928), 133-133 DOI: 10.1038/422133a

S SCAILLET, G VITASCAILLET, H GUILLOU (2008). Oldest human footprints dated by Ar/Ar Earth and Planetary Science Letters DOI: 10.1016/j.epsl.2008.08.026

When the headlines behind this story came across my RSS reader the other day, I was gonna file it under my proverbial “Captain Obvious” category. The basic premise is the potential link between last name and Y chromosome type. We already know that in deep ancestries, like among Jewish people, the Cohen Modal Haplotype (CMH) is notably frequent amongst Cohens. Cohens are a lineage of Jews believed to be direct relatives to the Biblical Aaron. They have a relatively strict marital tradition, one where the last name is preserved paternally.

Many other cultures are structured paternally and last names are inherited, for the most part, from the father’s family. Turi King made this otherwise obvious observation and tried to look for similar Y-chromosome haplotypes among two and half thousand men with 500 different last names. She presented her results to the Doctoral Inaugural Lectures being held in the Frank and Katherine May Lecture Theatre, Henry Wellcome Building, University of Leicester last week.

While not as deep as Cohens, there should be a linkage with almost any man’s last name and his Y-chromosome genetics… So long as name changes, adoptions and multiple foundations of the same last name by different individuals (like Smith) haven’t been prevalent. And that’s why I changed my mind about posting this research. King explains,

“The last name Smith is a good example of this as it derives from the occupation of blacksmith so many men could have taken on the last name Smith. This means that instead of just one type of Y chromosome being associated with a last name, many different types of Y chromosomes would be associated with this single last name. On the other hand, for rarer names, there may have been just one founder for the name and potentially all men who bear that last name today would be descended from him and could be connected into one large family tree.”

When King compared the Y-chromosome makeup of non-related individuals limited down to 40 last names, she was able to see that last names like Attenborough and Swindlehurst showed that over 70% of the men shared the same or near identical Y chromosome types whereas last names such as Revis, Wadsworth and Jefferson show more than one group of men sharing common ancestry but unrelated to other groups.

Ultimately, King was able to show between two men that share the same last name, there is a 24% chance of sharing a common ancestor through that name but that this increases to nearly 50% when their last name is rare. For forensic scientists out there, especially forensic anthropologists who regularly deal with skeletal remains, this can be a godsend because a prediction of a male’s last name is potentially possible from DNA alone. Now disclaimer aside, the press release didn’t really mention her methodology, i.e. how many loci she compared. Of course, the more the merrier. Either way, I’m sure many out there will look forward to larger comparisons of last-name to Y-chromosome correlations.

Throughout my academic career, I have noticed a certain kind of bias between different academic fields. Many “hard” scientist seem to believe that the work done by “soft” scientists such as cultural anthropologists is less valid or true. Recently, due to a recent post by Maria Brodine on Rebecca Lemov’s “World as Laboratory” , I thought I’d share some of my thoughts. Science as a human practice has always intrigued me, and due to it, I have dedicated much of my time to studying it as such. What I have realized is that “science” (hard and soft sciences), like anything else humans do, is a practice engaged by certain groups of people in myriad ways. The notion that science is something other than a human practice that produces “facts” beyond fallibility, human error, bias, subjectivity, etc… is an outdated idea that many people still believe today.

The majority of people typically think of true statements produced by science (note that the notion of the scientist as a person is absent) as ahistorical, objective, produced by reason and the scientific method, and free from personal bias. Nonetheless, various studies of science have broken down those conceptions, and have painted a view of science as collective, historical, socio-politically negotiated, and contingent on technology (from here on I will refer to this collectively as the contextual dimensions). As Bruno Latour explains in his book Laboratory Life, facts are removed from social and historical circumstances. (LL pg 105). They lose all temporal qualifications, and are incorporated into a larger body of knowledge (LL pg 106). In short scientific activity produces true statements in the form of facts, and in the process of doing so the contextual dimensions are lost.

Typically true statements in the form of facts are the result of two kinds of devices: technological devices and human devices. Both of these devices are the means by which scientist produce their beliefs, claims/statements, and compete with each other (and each other‘s statements), defeat each other, and remove the contextual dimensions. Human devices are any non-technological means which scientist employ that directly contribute to the statements they make.

Aside from lawyers and politicians, rhetorical/persuasive or human devices are used by scientist often. Latour’s naïve anthropologist in chapter 2 of Laboratory Life describes how the participants he/she studied worked to transform statements into more “fact-like” statements (LL pg73-84). The anthropologist at the end of chapter 2 suggests that by using literary inscriptions, photographs, and diagrams a reader of a statement is persuaded into accepting the transformation of a statement into a “fact-like” statement (LL pg88). Additionally, scientific writing is usually extremely technical and does not make use of personal pronouns. In doing so, scientific writing makes the author invisible, and predetermines the reader, which adds to the validity of the claims made.

In addition to using various kinds of rhetorical devices of persuasion such as different kinds of statements and ways of making those statements that render the authors invisible and make their statements appear more fact-like, often times scientist simply eliminate the competition that other scientist pose. For example, in chapter 3 of Latour’s Laboratory Life, the historian’s deconstruction of a fact shows the changes in context that occurred over time. One such change is the redefining of a field into a subspecialty. This redefinition allows the scientist to redefine standards and methodology such that the use of new equipment that is expensive is necessary. The costly equipment eliminates competition by eliminating scientist who are not sufficiently funded (LL pg122). A similar phenomenon is described in H.M. Collins’ introduction to his work The Golem. Collins explains how Einstein’s Theory of Relativity in combination with Einstein as a figure of authority, sparked contention within the physics community that eventually led to a refining of standards, which dictated what counted as valid. Once the “culture of life in the physics community changed”, previous experiments that may have been considered relevant, were no longer so (The Golem pg42).

The elimination of competition, as described by both Latour and Collins, is the result of a human device. This human device is the strategic use of the political and social dimensions of science. In Latour’s case study of TRF(H) in Laboratory Life, the political and social work done by Guillemin and Schally was complaining that the field was outdated, that claims were unfounded, and that elegant hypotheses substituted for facts (LL pg122). Their complaining directly contributed to the redefinition of a subspecialty, elimination of scientists who did not meet the new standards, and to the production of scientific facts.

Collins in his work The Golem is more explicit. An interpretation of Collins work in The Golem is that the success of a statement depends on the success of its authors. When an author of a theory or statement becomes extremely successful, their statements, and other statements either derived or implicated, also become successful. This is extremely obvious in the social sciences, but not in the “hard” sciences. Nonetheless, according to Collins, upon close examination we see that because of Einstein’s figure of authority and genius, his theory was successful. After consensus (which is the result of human and technological devices) was established regarding the validity of Einstein’s theory, various confirming data was reported. Discrepancies that previously plagued the work of other researchers, and inhibited them from drawing conclusions supporting Einstein, disappeared (The Golem pg53). Collins writes that scientific consensus moved from the center occupied by Einstein’s theory, and spread in all directions from that center. This was all the result of “agreement to agree about new things” (The Golem pg54). These new things primarily were derived or implicated from the center, which was the result of possibly part genius, and mostly the social and political dimensions of science.

With that we turn to technological devices. Technological devices used in science range from measuring devices (e.g. test-tubes, mass-spectrometers), experimental devices (e.g. prisms, lasers, gravitational radiation detectors), and one can even argue that the tap water in the laboratory is a technological device. We can broadly define technological devices as any non-human means which scientist employ that directly contribute to the statements they make in the ways discussed earlier. In this way, for example, the tap water is a technological device because it directly contributes to the work in the laboratory, and hence the statements produced by the scientists. If the tap water was to be shut off, scientific activity within the lab would stop. Technological devices are a necessary part of scientific activity among scientists today.

Interestingly, technological devices and their use is intimately entangled with human devices. To illustrate this consider the following: Before a statement is deemed true, consensus regarding what counts as a proper experimental device must be made. Without consensus, any scientist can claim that their results obtained by way of technological devices accurately represent reality. Consensus is negotiated using human and technological devices. Negotiations are made regarding which set of experiments and instruments are competent. Various adjustments are made to methodology, standards, and instrumentation. Collins illustrates this process in his work The Seven Sexes. In this work, Collins describes what he calls the enculturational model. Through this model, knowledge regarding instrumentation is passed down through enculturation. He writes that the only criterion to establish that the knowledge necessary to conduct a proper experiment with the competent technological devices is that the experiment works. What counts as working is negotiated. Furthermore, in coming to a consensus through the process of negotiation, the character of the phenomenon that is under investigation is also decided (The Seven Sexes pg219). Once the phenomenon under investigation is decided, any other experimental devices used by others are deemed inadequate if they do not support the decided upon characterization of the phenomenon. In this way the claims made by scientist using different technological devices, which are always entangled with human devices, are unsubstantiated.

Latour in chapter 2 and 3 of Laboratory Life gives a similar account, but more interestingly he discusses how technological devices can lend validity to a claim. According to Latour’s naïve anthropologist and historian‘s deconstruction of a fact, the claims scientist make are all contingent on technological devices they use. The anthropologist describes in chapter 2 how the participants use specialized equipment to transform pieces of matter into written documents (LL pg51). The participants rewrite and edit the output of the recording equipment several times. The documents produced are then inserted within a larger network of actors (LL pg54). A document is said to be a fact or contain a fact when all the actors are convinced that there is no debate about the fact they are reading (LL pg 76).The process of constructing a fact, according to my interpretation of Latour, begins with technological devices and ends with technological devices. The construction of a fact begins with recording equipment described in chapter 2. In chapter 3, only after TRF(H) has been measured using another technological device, the mass-spectrometer (LL pg146), does it become a fact.

In using technological devices and human devices, the contextual dimensions discussed above are stripped away. Both kinds of devices function to produce claims/statements, allow scientist and their statements to compete with each other, defeat each other and remove the contextual dimensions that allowed the fact to be produced. The examples we discussed thus far exemplify how facts are produced and the contextual dimensions erased. For instance, by using technological devices to convert physical matter into output, a scientist can claim that personal bias was eliminated by using human devices. By using human devices that render the authors invisible, the social, political, and historical dimensions (e.g. previous research that was deemed irrelevant or invalid, but yet contributed to the production of the fact) that contributed to the production of a true statement in the form of a fact are erased.

One interpretation of Collins’ The Seven Sexes is that in deciding what the phenomena under investigation is, the nature of the phenomena is characterized and that characterization becomes fact because there is agreement regarding the nature of the phenomena. But what about truth? Does agreement somehow substantiate truth? Is the agreed upon characterization true? According to the common-man, a statement is said to be true when it corresponds to reality. According to this definition of truth there are several statements that can be said to be true, e.g. “you are reading this post” is a true statement because it corresponds to reality. A fact then can be said is a statement that scientist make which corresponds to reality. But which came first, reality or the fact? Was the statement “you are reading this paper” true before you read it? According to my interpretation of Collins, reality would have to come first.

Latour’s work in Laboratory Life takes a more radical step. Latour argues that once the phenomena under investigation is decided and it becomes a fact, nature itself is created. In a way this seems to imply that nature, science, and society are all co-constructed. Furthermore, the answer to the question asked regarding what came first, would be both because in the production of a fact, nature is produced as well. Latour’s answer seems better because it captures the phenomenon of the production of facts and reality more adequately. Before reading this post the statement “you are reading this post” is not true, but has the potential to be true. After reading the statement and the post in its entirety, the statement “you are reading this post” is still not true. Only in the act of rendering the statement true, does the reality become true (and vice versa). As soon as the facts change, the reality changes as well. Interestingly, this co-construction of nature and fact reinforce each other. In co-producing true statements in the form of a fact and nature, nature reinforces the true statement, and the true statement reinforces nature. In a sense, this is the last nail in the contextual dimensions’ coffin. Once “nature-and-true-statements” are produced, both the phenomenon in nature and the true statement work together to completely remove the contextual dimensions by appealing to the common-man‘s conception of truth. True statements in the form of facts correspond to a reality which is created by the production of the true statements in the form of facts. Ultimately, we end up with incontrovertible commonsensical facts such as “of course the world is made up of atoms”, “of course gravity exists”, “of course I believe in reality”, “of course demons aren’t real”, and yes “of course race is real”.

H. M. Collins (1975). The Seven Sexes: A Study in the Sociology of a Phenomenon, or the Replication of Experiments in Physics Sociology, 9 (2), 205-224 DOI: 10.1177/003803857500900202

Earlier this year, I wrote a massive summary on the genetics of pigmentation for one of my graduate courses. I wasn’t particularly keen on the topic before but it has since grown on me and I’m now a big fan. So to read from Yann, Dienekes, and Razib that one of the key pigmentation genes, SLC45A2 is involved in hair color among Polish people, I was both excited and, well, frankly not very surprised.

Before I drag you into a review of the paper let me first introduce the gene and its function. SLC45A2 stands for solute carrier family 45, member 2. It is found on the short arm of chromosome 5. Not very informational, but the protein it ultimately encodes for is known as membrane-associated transporter protein (MATP). As the name implies, this protein is thought to regulate traffic melanosomal proteins into melanosomes, organelles within pigmentation cells (melanocytes) where melanin is produced. Melanin functions as a protective agent. It is dark in color and accumulates in cells in reaction to sunlight, absorbing light and protecting the nuclear genome from mutations caused by the ionizing radiation from UV rays. Thus, making MATP and the genetics of SLC45A2 an important part of the skin pigmentation pathway.

Recent studies have shown that certain variants of MATP affect pigmentation, such as Cook et al., 2008 and Graf et al., 2007. In the latest piece that everyone is buzzing about, “Association of the SLC45A2 gene with physiological human hair colour variation,” the authors were able to make an significant association between one of two non-synonymous polymorphisms in SLC45A2 and the hair color phenotype of a Polish population.

Inspired by Razib's example: Marzena Cieslik, Miss Poland 2006

The two SNPs are rs26722 and rs16891982. Both are missense mutations that encode for a different amino acids. The first SNP, rs26722, is a change from a guanine base to an adenine at position 907 of the mRNA transcript. This swap to an adenine affects the resultant the codon, creating a lysine on position 272 of the amino acid sequence instead of a glutamic acid residue (annotated as E373K). Similarly, rs16891982, is also a switch of a guanine but for a cytosine base on a different position of the transcript, 1214. The leucine residue on position 374 is thus changed to a phenylalanine (annotated as L374F).

Biochemistry aside, these two end products, MATP-E272K and MATP-L374F, have distinct population frequency distributions, especially MATP-L374F. Among the Polish sample of 392 individuals of varying skin, hair, and eye color, the rare allele is L374… Found in only 2.3% of the population. The MATP-374F allele is represented in 97.7% of the Polish sample. Curiously, all people who carried the rare allele had dark hair. The authors calculated the odds the L374 genotype increased the likelihood a person would have dark hair by 7 times.

Razib linked up an awesome resource, called ALFRED, the allele frequency database which shows the distribution of rs16891982 world wide. You can see that in northern Europe, 374F is the prevalent allele. Only when you get to Italy, Spain, Turkey, do you begin to see more of the L374 allele (the dark hair allele).

Worldwide Distribution of the rs16891982 SLC45A2 Allele

This all makes sense, people who carry a cytosine on position 1214 of the SLC45A2 mRNA have lighter color hair than those who carry a guanine (L374). A similar distribution frequency was observed a German and Japanese sample by Nakayama et al., 2002 & Yuasa et al., 2004 & Yuasa et al., 2006. 96.5% of Germans had the lighter 374F allele. 100% of Japanese had the darker L374.

But why?

I returned to one of the previous studies I mentioned earlier, the Cook et al. paper, “Analysis of Cultured Human Melanocytes Based on Polymorphisms within the SLC45A2/MATP, SLC24A5/NCKX5, and OCA2/P Loci.” The authors of this paper grew primary melanocytic cells with specific mutations and tried to see the effects they had on melanin content and tyrosinase activity. In their array, one of their comparisons included the impacts of the MATP-L374 variant to the MATP-374F variant. They found that MATP-L374 cells expressed significantly lower MATP transcript levels compared to MATP-374F ones.

I’ve spent a lot of time thinking about this and quite frankly, I’m very confused. Correct me if I’m wrong, but lower levels of MATP transcript means less transport proteins translated and available to bring melanosomal proteins into the cells. Less building blocks equals less melanin. And less melanin should equal lighter pigmentation. So why do people who have dark hair have the less productive allele?

Come to think of it, there could be many different reasons, actually. Biochemical pathways are hardly ever a 1:1 mechanism. There’s lots of redundancy and sometimes one component isn’t the point man. For example, other parts of the pathway, such as tyrosinase, an enzyme that catalyzes the production of melanin, is higher in darker skin. Other transport proteins, such as SLC24A5/NCKX5 are also part of the melanin and melanosome production network and could have a different impact.

Either way, there are a few curious things to come out of all of this… We now know a definitive allele that affects hair color. Albeit, how is still up in the air, ’cause darker haired people come with less membrane-associated transporter proteins on their melanocytes. But still, there is a distinct structure to the distributions of these haplotypes.

Wojciech Branicki, Urszula Brudnik, Jolanta Draus-Barini, Tomasz Kupiec, Anna Wojas-Pelc (2008). Association of the SLC45A2 gene with physiological human hair colour variation Journal of Human Genetics DOI: 10.1007/s10038-008-0338-3

I mentioned the drawn out process of me trying to download this new paper, “Dynamics of Alliance Formation and the Egalitarian Revolution,” the other day. I’ve read it and although I found it to be a difficult and theoretically dense paper, I believe you should also read the open access piece if you have any interest in understanding how culture evolved and the possible mechanisms of egalitarian behavior early on in human evolutionary history. The paper’s first author is Sergey Gavrilets, a theoretical evolutionary biologist from the University of Tennessee, Knoxville. The other co-authors are also from the same institution.

You may know Gavrilets’ other piece on cultural evolution, the 2006 paper in which he and Aaron Vose built a mathematical model to test out the social brain hypothesis — creating situations where genes control brains which invent and learn strategies that are then used by individuals to gain advantage in competition for mates. He’s continued researching the evolution of social behavior, and in his most recent piece he and his team tackle the dynamics of coalition formation.

The observation that Gavrilets et al. make is that while our closest living evolutionary cousins form alliances and cooperate in groups, their social systems are extremely hierarchical. The most glaring example can be seen in a gorilla troop where a dominant silverback presides over a few adolescent males and a harem of females. The group dynamic is fluid throughout life history, but each member of the system ultimately plays a role in the dominance hierarchy.

But early human societies, such as the quintessential hunter-gatherer society, is generalized as being egalitarian. Prior to the agricultural revolution, hunting and gathering is thought to have been the only subsistence strategy deployed by early human cultures. Studying modern day hunter gatherers, ethnographers have noted that such societies distribute dominance much more equally and thus tend to be non hierarchical. Leaders are comparatively weaker than their subordinates which reverses the pyramid of power.

So why was there such a big behavioral shift during our evolutionary history? We may never know for sure. There are ideas floating around that all seem to suggest the lack of food and realization that cooperation, rather than competition, was more beneficial for overall survival. When food sources became more dependable, as seen after the Neolithic and the dawn of agriculture and pastoralism, is when we’ve seen a return to a traditional hierarchy.

Gavrilets and team created a complex model which ultimately relied on probability to solve problems. They simulated alliance formation among a group of individuals who had different fighting abilities. Their system distinguished between conflicts that existed only between pairs of individuals and conflicts that were composed of more than two individuals. In situations that conflicts existed solely between two individuals, a very structured hierarchy emerged, favoring the ones best able to fight for their interests. In situations that composed of more than two individuals, there was interference or a balance of power, where the hierarchy was biased towards one result over another.

With an increase of group size, Gavrilets et al. were able to see an increase in dyadic conflicts. When members of a group were aware of other conflicts, of which they were not directly related, there was also an increase of dyadic conflicts. Naturally, larger coalitions have a higher probability of winning a conflict and a positive outcome increased affinity between members of the coalition.

Again, this was a rather hard paper to read, and I’ve left out a lot of details. I’m a bit unclear about what was rewarded to drive forward the model, i.e. what were they fighting for? Some of you may write off models as being controversial and reductionist. You’re right. For starters, it is difficult to interpret methods and the data doesn’t seem like it factors in the interactions of so many different variables — some come from evolutionary, ecological, behavioral, and social factors and all acting simultaneously. It is also awkward to evaluate relevant time-scales, aside from generation turnover, and to figure out possible evolutionary dynamics.

But the model did show that the tendency towards egalitarianism is rapid — it consistently happened in the course of several generations. Under situations where all members of a group were a part of one alliance, where not all members were equal, they still remained united. But alliances weren’t permanent. They would phase and out of intensity. Outsiders were also a crucial part of keeping the dynamic alive.

Gavrilets and crew suggest that egalitarianism came along with changes in mating systems and influenced by primate mother-daughter bonding. They also noted that the emergence of language most definitely facilitates the formation of alliances. One last thing, the authors sent out a warning against considering modern day humans under such constraints, because when we join alliances, our decisions are strongly affected by how much we perceive to get out of the alliance versus the costs and risks of being a part of the alliance, which are factors not included in the model.

All aside, this model is informative but it is by no means the way human social behavior evolved. I’ve already outlined some of the caveats to modeling. To further supplement, there are exceptions to the rule that all hunter gatherer societies are/were egalitarian. Non-egalitarian hunter gatherer systems, such as the Haida, have been well documented by ethnographers. I also remember one of my anthropology professors telling me her accounts of living with outcasted Dassenach people. They were forced out of the pastoral lifestyle and into a hunting for crocodiles and fish one. But, they still retained the social structure despite the shift in subsistence.

Sergey Gavrilets, Edgar A. Duenez-Guzman, Michael D. Vose, Erik I. Svensson (2008). Dynamics of Alliance Formation and the Egalitarian Revolution PLoS ONE, 3 (10) DOI: 10.1371/journal.pone.0003293

In World as Laboratory, Rebecca Lemov, an anthropologist, writes for a larger audience.

“I think it’s too bad that a lot of scholarly work never gets read, usually because it’s just plain difficult to read,” she says in an interview with Nicole Merritt of MyShelf.com. “Being difficult is sometimes necessary, but sometimes there’s deliberate obfuscation going on … ‘If you can’t understand what I’m saying, I must be exceptionally smart’.”

David Brooks reviewed it at The New York Times, an honor not always bequeathed to anthropological texts.

The paperback is published by Hill and Wang, rather than an academic press, and the book is written in a humorous, even sarcastic tone, in accessible language that feels like a leisure read full of rich philosophical implications and shocking detail.  The focus of the work is how the laboratory became the locus of power and authority, the fountain of knowledge for social scientists and governments alike, eventually contributing to an extension of the laboratory to world settings – so that the United States, as a colonial power, utilized whole peoples for experiments on the premise that human behavior could be understood, controlled, and even engineered on a massive scale.

Lemov also describes how laboratory science, with its emphasis on objectivity and distance from the subjective – as well as the subject – is built around experiments on animals as the ideal approach to studying human behavior and, yes, even the social.  Yet this practice is built on a puzzling paradox: although humans are assumed to function behaviorally in the same manner as animals, animals as nonhumans (and, in some cases, certain humans considered less than civilized) are permissible subjects of often painful and exceedingly demoralizing experiments.  Furthermore, as Lemov demonstrates, laboratory science itself was generated by personalities, men in fact caught up in a range of personal fears and anxieties – in short, subjectivities.  Yet despite these contradictions, laboratory science built on the assumed subject-object, human-nonhuman distinction is as pervasive as ever, if not more so.

Without proposing any conspiracy theories – in fact, Lemov makes it clear that a lot of these guys were wayward do-gooders and philanthropists who couldn’t possibly know the full ramifications of their brand of science – she points to the lasting effects widespread ideas about the social self have on our lives even today, even in the marketplace, in malls, in everyday politics.

With the laboratory, Lamov writes, scientists “built a stressful world that predicted our own: a world in which stress and its effects can actually be engineered, ratcheted up, and in some sense capitalized upon” (101).

Admittedly, this sounds pretty incendiary for an anthropologist, and Lemov certainly doesn’t pretend to participate in any kind of dalliance with objectivity.  There is something very brave and honest about that.  Lemov is an anthropologist – a person with a PhD – but she clearly isn’t ashamed of her own biases, nor is she interested in putting on a veil with her thinking cap.  Perhaps more importantly, she’s talking about things that sound boring and inaccessible – science studies, subject-object distinctions, intentionalities – in a way that is likely to stimulate more dialogue and participation among a wider range of people than your standard stodgy academic article.

Not that those are unimportant.  It’s just that they, too, are part of the laboratory world.

Dienekes pointed out another interesting paper that I want to share with you, this time on Neandertals and evidence of the Uluzzian Industry as seen from the Fumane Cave in Italy. The paper was published by Marco Peresani in the journal Current Anthropology, under the title, “A New Cultural Frontier for the Last Neanderthals: The Uluzzian in Northern Italy.” Persani describes the archaeological assemblage of the 11 layers of Fumane Cave, of which the oldest layers, 11 through 5 are Mousterian typology and the latest, 2-1 are Aurignacian. Layers 4-3 are Uluzzian, and date right at a critical transition period during human evolution — the time at which Neandertals are thought to have gone extinct in Europe (around 30,000 years ago).

The term Uluzzian was coined by Palma di Cesnola in 1988 after the observed assemblages from sites around the Bay of Uluzzo, found on the Ionian Coast. Julien Riel-Salvatore, the blogger behind A Very Remote Period Indeed, studied the Uluzzian technology and has in fact published or presented several pieces on the emergence of the Uluzzian during the transitional period of the Middle to Upper Paleolithic.

The Uluzzian is characterized from the Mousterian by larger stone tools, some bone items others splintered cores (perhaps bidirectional cores), lots of unidirectional or bidirectional cores, few burins, end scrapers, side scrapers, etc. In general, a modest modernization of the Mousterian. Some of the most famous Uluzzian sites are La Fabbrica, Castelcivita, La Cala, Grotta Brenardini, Grotta di Uluzzo (the namesake site), Grotta del Cavallo all of which are found in Italy. The Vindija cave in Croatia and the Klisoura cave in Greeze are also considered Uluzzian sites. Fumane Cave is the northernmost, now-understood-to-be Uluzzian site.

Figure 3 from the paper. Uluzzian implements found in units 3 and 4: splintered piece (1), backed knives (2, 3, 6), implement with curved back (5), bladelet core (4) (drawings by S. Muratori and G. Almerigogna).

The animal remains found in the older, deeper Mousterian levels, such as ungulates and macromammals suggest that the inhabitants regularly hunted animals found in moist/cool ecosystems… perhaps an alpine environment. Like I mentioned, layers 4-3 represent a different tool set, as if the inhabitants were (desperately?) experimenting with different technology which was replaced with the distinctly different Aurignacian formal blades and retouched tools soon after. The authors also suggest that Fumane wasn’t persistently occupied during the layer 4-3 period. All of which suggests that these last Neandertals were trying very different cultural items. Why? They had perfectly find tools… or did they?

Marco Peresani (2008). A New Cultural Frontier for the Last Neanderthals: The Uluzzian in Northern Italy Current Anthropology, 49 (4), 725-731 DOI: 10.1086/588540