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paleoanthropology, genetics and evolution

history

  • Effective size through genealogy

    Thu, 2011-11-24 23:48 -- John Hawks

    Sandwalk: "What William the Conqueror's Companions Teach Us about Effective Population Size".

    Let's assume that there are 20 well-documented companions. Only one of these (William Mallet) has possibly passed on his Y chromosome to the present time and even that male line of descent is disputed. This is fully consistent with our understanding of genetics when you consider that most male lines are likely to die out in a few generations. Those that survive ten generations or so are unlikely to become extinct since there will likely be several male lines at that time.

    Only 10 of the companions have descendants who are alive today. This could be due to the fact that genealogists don't have perfect records for all the companions and their families but it's also quite in line with expectations.

    A nice illustration, with a link to my own review article (available free here), "From genes to numbers: Effective population sizes in human evolution".

  • Alfred Crosby interviewed

    Sun, 2011-10-30 18:13 -- John Hawks

    Last week I linked to an article about the dispersal of the potato ("How the Potato Changed the World"). Smithsonian also has an interview with Alfred Crosby, the historian who coined the term, "Columbian Exchange": "

    When you wrote The Columbian Exchange, this was a new idea—telling history from an ecological perspective. Why hadn’t this approach been taken before?

    Sometimes the more obvious a thing is the more difficult it is to see it. I am 80 years old, and for the first 40 or 50 years of my life, the Columbian Exchange simply didn’t figure into history courses even at the finest universities. We were thinking politically and ideologically, but very rarely were historians thinking ecologically, biologically.

    To me, this was the most interesting part:

    I had a great deal of trouble getting it published. Now, the ideas are not particularly startling anymore, but they were at the time. Publisher after publisher read it, and it didn’t make a significant impression. Finally, I said, “the hell with this.” I gave it up. And a little publisher in New England wrote me and asked me if I would let them have a try at it, which I did. It came out in 1972, and it has been in print ever since. It has really caused a stir.

    To me, Crosby's work marks a trend in which anthropology and archaeology were damaged by changing academic fashion. In Kroeber's time, quantitative study of the material things and their appearance in history was a central part of cultural anthropology and archaeology. Cases like the origin of the fire drill and the spread of the potato were the essential subject matter of a debate between diffusionist and evolutionist theories of culture change. Such cases mattered to anthropologists. By the 1960's, they mattered not so much.

    Historical economists and historians took up the subject. Today we are much more likely to see a "history of everyday things" written by a historian, and a popular work of "ecological history" is rather more likely than a popular work in ethnobotany.

  • Potato sack race

    Fri, 2011-10-28 14:30 -- John Hawks

    Smithsonian magazine has a very nice article by Charles C. Mann, "How the Potato Changed the World", focusing on the effects of the Columbian exchange on Europe.

    “For the first time in the history of western Europe, a definitive solution had been found to the food problem,” the Belgian historian Christian Vandenbroeke concluded in the 1970s. By the end of the 18th century, potatoes had become in much of Europe what they were in the Andes—a staple. Roughly 40 percent of the Irish ate no solid food other than potatoes; the figure was between 10 percent and 30 percent in the Netherlands, Belgium, Prussia and perhaps Poland. Routine famine almost disappeared in potato country, a 2,000-mile band that stretched from Ireland in the west to Russia’s Ural Mountains in the east. At long last, the continent could produce its own dinner.

    When I toured through the Altai this summer, I was impressed at the healthy potato patch outside nearly every house. How unlikely it seems that this American crop should have become a central part of people's lives in some of the most remote parts of Central Asia.

  • Hollywood's war on Shakespeare

    Thu, 2011-10-27 15:43 -- John Hawks

    The New York Times Magazine tries for a new record in academic killjoy columns: "Wouldn’t It Be Cool if Shakespeare Wasn’t Shakespeare?"

    Professors of Shakespeare — and I was one once upon a time — are blissfully unaware of the impending disaster that this film means for their professional lives. Thanks to “Anonymous,” undergraduates will be confidently asserting that Shakespeare wasn’t Shakespeare for the next 10 years at least, and profs will have to waste countless hours explaining the obvious. “Anonymous” subscribes to the Oxfordian theory of authorship, the contention that Edward de Vere, the 17th earl of Oxford, wrote Shakespeare’s plays. Among Shakespeare scholars, the idea has roughly the same currency as the faked moon landing does among astronauts.

    Oh, criminy. Just like undergraduates have been confidently asserting for the last decade that the boy actors in Shakespeare's time were actually women who look a lot like Gwyneth Paltrow and really wanted to get it on with the bard?

  • Charles Mann interview

    Fri, 2011-09-02 09:53 -- John Hawks

    Razib Khan posts an interview with author Charles C. Mann, whose new book 1493: Uncovering the New World Columbus Created is an account of the social and ecological effects of the Columbian exchange on the peoples of the Americas.

    I knew that Asians had worked under brutal conditions on the railroads. But I had no idea that something like 250,000 Asian slaves had been taken to the Americas in the 19th century. Similarly, I suspect that most Mexicans don’t know that Mexico City had a thriving Chinatown by the early 1600s. And most Peruvians don’t know that Asians were a significant presence in Lima as early as the 1611 census. And so on.

    I liked his earlier book, 1491 a lot, and I'll be reading the new one soon.

  • Mummy trouble redux

    Thu, 2011-04-28 22:56 -- John Hawks

    Speaking of Jo Marchant, she has a long article in the current Nature about the mummy DNA controversy ("Ancient DNA: Curse of the Pharoah's DNA").

    I wrote about the problem earlier this year: "Mummy troubles". My opinion is that this work has been relentlessly hyped and hasn't presented adequate information to assess whether the results are genuine:

    Can we accurately type STR alleles from mummies? I wouldn't rule it out given the quantity of tissue available, but there should be many more controls for a high-profile study like this one. The work took place over several years, so it's a bit unrealistic to expect the latest sequencing methods. But JAMA and the Discovery Channel presented the results as important science. They should have ensured that solid answers for the obvious questions were at hand.

    Marchant digs up some quotes from the authors:

    The researchers deny that the television involvement put them under excessive pressure to produce dramatic results. But working for the cameras did make a challenging project even tougher, says Pusch. "Each time they came in to film, we had to close the lab for a week to clean." Eventually the TV crew was banished and the lab scenes reconstructed.

    The article gives an interesting sociology of the competing groups of ancient DNA researchers. I dispute that the field is evenly divided, however. There are a very long list of laboratories doing ancient DNA work according to standardized protocols on skeletal remains from the past several thousand years. Only a few groups claim to be working with nuclear DNA or microbial DNA, the areas of contention in the mummies. Among that small set of labs, most follow similar, conservative techniques.

    Then there are the handful that come up with "surprising" results time and again. If the surprising results are accompanied by substantial evidence, I have no problem. But when a paper has no clear explanation why it arrives at results that others think impossible, that raises my skepticism.

  • Fogel profile

    Tue, 2011-04-26 18:13 -- John Hawks

    The NY Times has a profile of economist Robert W. Fogel ("Technology Advances; Humankind Supersizes"). Fogel, along with other historical economists, has worked to document the changes in human stature, mass and health during the last few hundred years. These changes were mostly not evolutionary. That is, it wasn't genetic change that made us bigger, for the most part.

    The documentation of these trends has made for a fascinating series of historical studies. The occasion for the profile is the upcoming release of a book by Fogel and colleagues summarizing the decades of work.

    To take just a few examples, the average adult man in 1850 in America stood about 5 feet 7 inches and weighed about 146 pounds; someone born then was expected to live until about 45. In the 1980s the typical man in his early 30s was about 5 feet 10 inches tall, weighed about 174 pounds and was likely to pass his 75th birthday.

    Across the Atlantic, at the time of the French Revolution, a 30-something Frenchman weighed about 110 pounds, compared with 170 pounds now. And in Norway an average 22-year-old man was about 5 ½ inches taller at the end of the 20th century (5 feet 10.7 inches) than in the middle of the 18th century (5 feet 5.2 inches).

    This stuff is tremendously important for human biologists to understand, and the data have become enormously richer in many respects as historical economists have drawn together records about military conscripts, food allowances and disease rates.

    The second part of the profile goes into some areas of criticism for Fogel (he focuses mainly on nutrition, other scholars argue for the importance of different causes). I think it is time to integrate a more evolutionary view into the data on recent secular trends. The Framingham study and other longitudinal surveys have demonstrated differential fertility associated with stature in contemporary industrialized societies. Evolution is happening, and does not necessarily go in the same direction as the secular increase in stature. Meanwhile, population differences in stature and other traits owe to a deeper history that includes different causes.

  • Darwin's Y

    Fri, 2011-04-01 08:20 -- John Hawks

    The Telegraph has done a puff piece about the Genographic testing of Charles Darwin's great-great-grandson.

    Last week I got to attend an incredible panel discussion that focused on the issue of genetic testing and identity. How and why do people connect the results of a genotyping test to their deep conception of themselves?

    The Genographic results are only Y chromosome and mtDNA, a tiny fraction of an individual's ancestry. Charles Darwin only accounts for around 6 percent of this descendant's ancestry (possibly a shade more genetically, considering the inbreeding). The Y chromosome is not the seat of the soul. And yet:

    Mr Darwin, whose great-grandfather was Darwin's astronomer son George, said the test showed that the desire for knowledge and thirst for discovery was in his genetic makeup.

    "I was always a bit concerned that I hadn't inherited Charles Darwin's scientific abilities, but I hoped I had inherited his adventurous abilities, his desire to go over the hill and see what was on the other side," he said.

    Interesting how people construct a story about the connection between genes and identity, isn't it?

  • Quote:Neil Stephenson on America

    Fri, 2011-03-25 11:00 -- John Hawks

    I like this quote from Neil Stephenson, in his work, "In the beginning was the command line."

    The twentieth century was one in which limits on state power were removed in order to let the intellectuals run with the ball, and they screwed everything up and turned the century into an abattoir. . . . We Americans are the only ones who didn’t get creamed at some point during all of this. We are free and prosperous because we have inherited political and value systems fabricated by a particular set of eighteenth-century intellectuals who happened to get it right. But we have lost touch with those intellectuals.

    (quoted by Glenn Reynolds)

  • Ham the space chimp

    Sun, 2011-01-30 15:15 -- John Hawks

    Remembering Ham, 50 years later: "The chimp that took America into space."

    Fifty years ago tomorrow an African-born astronaut made it into space ahead of Soviet pioneer Yuri Gagarin. His name was Ham, a chimpanzee born in July 1957 in the rainforests of what was then the French Cameroons. He was bought by the US Air Force to be used in early space flight experiments for $457 – not a bad investment as it turned out.

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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.