Osteology in the Carolinas

I attended the first meeting of the Osteology in the Carolinas Interest Group (OCIG) this past Saturday (2/8). The event was organized by Gwen Robbins Schug (Appalachian State) and Dale Hutchinson (UNC-Chapel Hill) and was held at UNC-Chapel Hill. The purpose of the group is to be "a gathering focused on the analysis and interpretation of human skeletal remains from contexts pertinent to bioarchaeology, forensic anthropology, and paleoanthropology." In his introductory remarks (after showing off a hilarious t-shirt ode to syphilis), Dale noted that most researchers with these interests often fall between traditional disciplinary boundaries, so the group was meant to fill that gap.

Thirteen papers were given, and I would say that there were between 20-30 attendees. I was only able to stay for part of the morning session, but those papers that I did see were very interesting. Some snippets from my notes of the meeting:

• Chin-hsin Liu (Appalachian State) presented on the bioarchaeology of Bronze and Iron Age burials from Thailand. It was nice to hear from an area and time period about which I know almost nothing. Chin-hsin did say that many of the skeletons could not be analyzed in detail since they are left exposed by the state for tourism. Isotopic data indicate that populations tended to eat more-or-less the same diets even as they experienced a number of techno-sociological changes from the Bronze to Iron Ages.
• Sara Juengst, a PhD student from UNC-Chapel Hill, spoke about her research in the Titicaca Basin of Bolivia. She discussed how strontium isotope data can be used to identify the geographic area where individuals grew up and lived. Using this data, she found that a couple of the analyzed burials contain "non-local" individuals that were, perhaps, she suggested, pilgrims from other regions.
• Chuck Hilton, our colleague at UNCG, gave a really interesting talk on his research with human remains from Alaska. Essentially, he is interested in tracking skeletal changes associated with the shift from caribou- to whaling-based subsistence economies among Alaskan foraging populations a couple thousand years ago at a site called Point Hope. Chuck noted that data on the skeletal health of forager populations tends to be limited, as they are highly mobile and do not typically produce large cemeteries. Luckily, there are around 400 skeletons from this site, and Chuck found, intriguingly, that the folks practicing whaling were much less healthy than the earlier, caribou-hunting, people. Tuberculosis was especially prevalent in the former population (Chuck suggested that this could be linked either to increased marine mammal consumption or contact with infected NE Asian populations). The question becomes, of course, if whaling had such negative repercussions for health, why practice it? I was wondering if this isn't an example of costly signaling−whaling is, after all, a dangerous and, as Chuck put it, "boom or bust" proposition, so perhaps the individuals that engaged in it gained added prestige (and, thus, mating opportunities). I'll have to get his take on this.
• Megan Perry (East Carolina) talked about her team's work at the very famous site of Petra (you may recognize the picture below from Indiana Jones and the Last Crusade−this is the city's treasury building). Orthodox thinking tells us that as a large, cosmopolitan urban center, Petra would have been ridden with diseases. However, preliminary analyses of the human remains suggests a surprisingly healthy population, and Perry and her team plan on testing this hypothesis further. 

  

  The treasury building at the ancient Nabataean city of Petra (courtesy of UNESCO).

• The last talk that I was able to hear was from Dan Temple (UNC-Wilimington). He was looking at human life history trade-offs with a collection of Jomon skeletal remains. Some background: bodies only have so much energy to delegate to various tasks like growth, maintenance, and reproduction, and life history theory is interested in understanding how the body uses these limited resources. Almost all individuals undergo some sort of stress early in development (low birth weight, disease, etc.), and human physiology is plastic enough to devote extra energy to combat these. The question is how does this impact the rest of an individual's life? Temple tested two models: (1) that these early stressors actually better prepare individuals for other setbacks later on; and (2) that the extra energy used early on in development actually makes those individuals more susceptible to later insults (a "borrow now, pay later" sort of idea). Using linear enamel hypoplasias, which are imperfections in the formation of tooth enamel that reflect episodes of stress, Temple found that those individuals affected by hypoplasia earlier on in their lives had more pathological conditions later on and lower life expectancy. This supports the "borrow now, pay later" hypothesis.

There were a number of other talks that I'm sorry I missed, including our department head, Bob Anemone, who talked about his predictive geospatial modeling, Steve Churchill (Duke), who discussed new hominin discoveries in South Africa, and Mark Teaford (High Point University), who talked about the latest in dental microwear. Looking forward to attending this get-together in the future.

The ironies (and absurdities) of slavery in the early American republic

I just finished with Alan Taylor's The Internal Enemy: Slavery and War in Virginia, 1772-1832. The "internal enemy" is a term that whites often used to refer to the slaves in their midst since, as Taylor demonstrates, slave insurrections were a nearly constant fear among Virginia's slaveholders. I would highly recommend the book for those of you who are interested; here I just wanted to mention a few tidbits from the book that stuck out for me and, at the same time, highlight the sometimes highly paradoxical viewpoints that Virginia's slaveholders were forced, either intentionally or not, to maintain in order to preserve an economic system that was a large part of their cultural identity:

• The elimination of primogeniture and entail. These refer to the practices of, respectively, the inheritance by the firstborn child of the entirety of a family's estate and the restriction of inheritance to the family heirs only. When practiced, as they were in colonial America, these laws served to concentrate wealth among a small number of families and, within those families, a small number of powerful individuals. After the American Revolution, these laws were struck down in many of the former colonies, including Virginia. While American lawmakers (including most prominently Thomas Jefferson) felt that the elimination of such laws was more consistent with a republican form of government, it was actually devastating for slave families. In essence, primogeniture and entail prevented wealthy plantation owners from scattering their estates after their deaths. For slaves, this significantly reduced the likelihood that family members would be sold off. With the suppression of these laws after the revolution, wealth was more evenly distributed among whites but, at the same time, the breakup of slave families became easier and much more common.
• Blacks' lack of rights. In 1816, George Boxley hatched a plot to lead about 30 or so slaves (some of which were his own) to freedom in the North as revenge for being passed over for a militia promotion and a seat in the state legislature, both of which he blamed on the state's wealthy, slave holding elite. The plan never materialized, however, and Boxley was eventually arrested. Here's the catch, though: all the witnesses to the treasonous plot were black and therefore barred, by Virginia law, from testifying against a white man! I'll let Taylor (2013: 399) finish the story: "[u]ncertain what to do with Boxley, the authorities kept him in jail until...he escaped after breaking his irons and cutting a passage through the ceiling of his cell...[s]uspicions arose that some powerful local people wanted Boxley gone rather than risk an embarrassing trial that would acquit for lack of evidence." How's that for irony?

References:

Taylor, A (2013). The Internal Enemy: Slavery and War in Virginia, 1772-1832. W.W. Norton, New York.

Ashby Dialogue, Part 1

So, this semester (Spring 2014), the Department of Anthropology at UNCG, along with the Departments of Biology and Interior Architecture, are organizing and hosting an Ashby Dialogue, which, through an endowment from the College of Arts and Sciences, "provide the opportunity for informal but focused inquiry into some topic or issue" of interest to university faculty and students. I helped a bit in the planning and organizing, but the lion's share of the work was done by our own Joel Gunn and biology's Malcolm Schug. Our theme for this semester is "Human Adaptation: Past and Future," and you can see the full schedule of events here. This is the first of several posts I'll provide throughout the semester as we progress through our program.

To kick off the schedule, we had hoped to have a talk from Greg Wray, a top-notch evolutionary biologist from Duke University who is interested in the evolution of gene regulation. Unfortunately, the winter storm (defined in North Carolina as a threat of snow or, in our case, an inch or so of snow) we had last week shut down campus and we had to cancel. Nevertheless, we did go forward with our first discussion session on Monday, February 3, and I'll recap that here.

The theme of our first session was How do Biologists Study the Question: What is the Evidence for Adaptation in Humans? There were a total of 10-11 people, including students from both anthropology and biology. We had posted a reading about next generation sequencing of genomes and two videos, one from Evan Eichler (Washington University) about structural variation in the human genome, and another from Sarah Tishkoff (University of Pennsylvania) about variation among modern African populations and evidence for the evolution of lactose tolerance, all of which served to focus our discussion.

We started off with an introduction from Malcolm, who gave us a great overview of the issue of genetic adaptation. He noted first that although "adaptation" can be viewed somewhat differently by anthropologists and biologists, Darwin's theory of natural selection and its focus on reproductive success serves to unite both fields. Biologists traditionally thought that because organisms appeared so well adapted to their environments that very little genetic variation would be present. This idea was blown apart by the work of Richard Lewontin and John Hubby, who in the 1960s documented a surprising amount of inter-individual variation in various proteins (this work was done first with flies and then, later, with humans). Further work by Martin Kreitman found tons of variation in DNA. All of this raised an important question: why the heck is there so much genetic variation between individuals if populations are supposedly well adapted to their environments?

Well, two answers emerged. One, which I'll dub the "adaptationist camp," thought that most of this variation was driven by natural selection (in this sense, inter-individual variation it is actually an adaptation in itself, since this variation will provide natural selection with something to work on). The issue then became to find the specific genes that were being selected for. The other side, which I'll call the "neutral camp," felt that most variation arises by random drift and alleles that have little or no effect on the survivorship of individuals. The debate was pretty acrimonious, but it seems like most folks recognize that both forces are probably at play.

To complicate matters further, Allan Wilson later suggested that perhaps it wasn't the genes themselves that were being selected for, but rather their regulation (i.e., when they are turned off and on, or how strongly they are expressed). Their is, for example, evidence that the human opposable thumb (the length of which permits us to manipulate small objects with ease) evolved not because of some structural change in a specific gene, but rather a change in when (and for how long) the genes responsible for the development of the hand were "turned on."

As Malcolm and our reading pointed out, the rapidly progressing genomic sequencing technology (it took years to sequence the first complete human genome about 15 years ago; we can now sequence entire genomes for everything from bacteria to human in DAYS) now permits huge amounts of data to be mined for evidence of natural selection. Now, geneticists can fish through whole genomes looking for gene that have undergone, or currently are undergoing, selection. I asked Malcolm how one goes about doing this, and he said that, essentially, geneticists scan the genomes of many individuals looking for allele frequencies that are higher (or lower) than expected (this can be determined statistically). I wonder if the technology is outpacing our ability to actually analyze it in a systematic way? Very interestingly, Malcolm told us about a study that simulated the evolution of a fruit fly genome and went back and identified "selected" genes with these statistical methods. Many were found, but the simulation did not include natural selection! So, it is by no means clear in every case whether or not genes have undergone natural selection.

Anyway, the clearest evidence for natural selection among most studies comes from genes identified with pathogen pressure and/or immune function and gametogenesis. Some other genes that appear to have been under selection over the course of human evolutionary history are FOXP2 (development of speech and language areas of the brain) and EDAR (development of several body tissues, including skin and sweat glands). We had additional conversations and discussions over pizza, including the issue of genetic determinism and how we define and analyze "traits."

Overall, a great start to our dialogues. I, along with Gwen Robbins Schug of Appalachian State, will be moderating our second session, which deals with past human adaptations to sedentism and urban life.