Linking archaeology and agrobiodiversity

It was probably a silly thing to say. A couple of days ago I briefly mentioned the models that researchers have built, based on present-day genetic data on Europeans, to understand the rate and pattern of human movement into the continent during the Neolithic. And I made the throw-away comment that I wasn’t aware of similar models for crops. I sort of instantly regretted it, and last night did some googling.

At first I thought perhaps I was right after all. I found a recent (2006) paper whose abstract says:

Thus far, no attempts have been made to track the movement of the founder genetic stocks of the first crop plants from their core area based on the genetic structure of living plants.

Further on, though, the authors say they’ve done just that for wheat. And I also found reference to a “Domestication of Europe” project which sought

to determine the extent to which phylogeographical analysis of modern landraces of barley and wheat, combined with examination of ancient DNA in preserved specimens, can reveal genetic information pertaining to the spread and establishment of cereal cultivation from its points of origin in Southwest Asia into and through Europe.

I think the project must have run from 2003-2006. The Glyn Daniel Laboratory for Archaeogenetics at Cambridge was one of the labs involved, and some of the work, and other related research projects, is described on its website.

So there are people out there trying to link up the archaeology and human genetics of agricultural spread in Europe with the genetics of crops and livestock. Is it too early for a Grand Synthesis?

The spread of agriculture into Europe

You may recall a post a few days back on how domestic pig keeping spread into Europe. Well, Razib over at Gene Expression, a genetics blog, has a post today which includes a map of the spread of agriculture north and west from the Middle East. He points out that current thinking is that either the practice of agriculture did the spreading (cultural diffusion), or people themselves (demic diffusion) — or both. Both was what the pig work implied, of course. Human genetic studies suggest that Neolithic people have made a fairly low (maybe 20%) contribution to European ancestry, and Razib summarizes the current debate about whether that therefore refutes the hypothesis that movement of people was involved in the spread of agriculture, as well as that of ideas. Bottom line: it probably doesn’t.

He also links to a recent paper that calculates a figure for the rate of movement ((Tracing the Origin and Spread of Agriculture in Europe. Pinhasi R, Fort J, Ammerman AJ. 2005. PLoS Biology Vol. 3, No. 12. doi:10.1371/journal.pbio.0030410)): 1 km/year, give or take. That was arrived at by interpolating radiocarbon dates of Neolithic archaeological sites across Europe, and it fits very well with the results of models using human genetic data. ((As far as I’m aware, however, nobody’s done anything similar with crops.)) An interesting way to think about that speed of movement is that it is roughly a one-day walk per generation.

Earliest known rice?

It’s late, and I really should get to bed, but I cannot ignore my duty to inform you of a paper just published in Nature. Fire and flood management of coastal swamp enabled first rice paddy cultivation in east China by Y. Zong, Z. Chen, J. B. Innes, C. Chen, Z. Wang and H. Wang describes how, 7,700 years ago, people in the lower reaches of the Yangtze converted brackish swamps into rice paddies that remained pretty productive for a couple of hundred years until the sea upped and swallowed the area. There’s a lot more to be gleaned from the paper, which is probably behind a paywall (I can’t check) but will nevertheless be picked up around the world. I’ll look out for a story in the China Daily tomorrow.

Later … Nothing I could see in the paper here, but the LA Times and National Geographic have more.

Roman antibiotics

Also from Tangled Bank comes news of a study looking at the evidence for various infectious diseases from the skeletons of people killed at Herculaneum by the eruption of Vesuvius in 79 AD. ((That’s the one that also destroyed Pompeii, though in a somewhat different way.)) Among the diseases was brucellosis, evidence for which was also gleaned from the carbonized cheeses found at the site. Herculaneum was apparently famous for its goat cheeses, which seem, however, to have been badly infected. Which is all amazing enough. But one of the commenters on the article points to another paper which adds a twist to the story.

It seems the inhabitants of Herculaneum, despite their brucellosis and tuberculosis, were relatively free of non-specific bone inflammations. And that may be because:

Pomegranates and figs, consumed by the population, were mainly dried and invariably contaminated by Streptomyces, a bacterium that produces natural tetracycline, an antibiotic.

Is there similar evidence from contemporary populations of the protection conferred by natural antibiotics?