Tuesday, 22 December 2009

the trouble with two-row barley

I still seem to be playing blog catch-up, but I had to record something from a few months ago, which should be forcing us to think about the prehistory of barley in a whole new way. .. Palmer et al. of the Warwick molecular archaeobotany lab group of Robin Allaby published a major paper on plant ancient DNA in PLoSone this summer, "Archaeogenetic Evidence of Ancient Nubian Barley Evolution from Six to Two-Row Indicates Local Adaptation." On the one hand it has some nice clear ancient DNA results from the Nubian site of Qasr Ibrim, which allows these samples to be placed phylogenetically in relation to the gene the control whether barley is two-row or six-row. They have found what at first seems counter intuitive-- that all the barley samples have the six-row mutation, despite the fact that Nubian barley is usually regarded archaeologically as two-row, based on its symmetrical grains.

Friday, 18 December 2009

Cereal in Libya earlier than Egypt? New data from Huah Fteah

The spread of agriculture to Egypt presents a number of contrasts from that in Europe of east of the Fertile Crescent. For one thing it seems to be long delayed, with our conventional dates for the earliest cereal agriculture in Egypt, such as in the Fayum at 5000-4500 BC-- by contrast cereal agriculture is established in Greece and Pakistan by 7000 BC. What is more Near Eastern animal domesticates (sheep and goat) had reached Egypt at least 1000-1500 years earlier and spread rapidly through the Sahara. New data from Libya, rather than the Nile, suggests a new wrinkle in this story: cereal agriculture did spread earlier (by 6000 BC?), and probably was established in part of the Nile Delta, but made little headway up the Nile. How have I come to this conclusion?  [ed. June 2010: but see my own comment on the radiocarbon dates that have now overturned this]

In the latest issue of the journal Libyan Studies (vol. 40, 2009), there is a long preliminary report on the new Society for Libyan Studies/ Cambridge project at the famous Haua Fteah rock shelter, and thereabouts, the "The Cyrenaican Prehistory Projecy 2009" As part of this renewed work systematic archaeobotany is being carried out both at Haua and at nearby Hagfet al-Gama. Results from the macro-botanical work by Jacob Morales (normally based on the island of Gran Canaria) are presented over a few pages in Libyan Studies (pp. 83-88), and seem to be highly significant, if understated. Seeds are generally few and not surprisingly most are wild species. But of note is the the occurrence of barley grains and free-threshing tetraploid wheat (T. durum) rachis from the 2008 samples of Hagfet al-Gama. These are yet to be directly dated, but the cultural association is with the socalled Lybico-Capsian period, characterized by being non-ceramic and conventionally termed "Mesolithic". The Neolithic, in which older work identified domesticated sheep and goats along with ceramics, dates from ca. 5500 cal.BC-- based on the the latest radiocarbon dates. These finds from the Lybico-Capsian then suggest that domesticated cereals, deriving from the Near East, were already present somewhat earlier. Of course we must await more data, and direct dates; as well as results from new faunal analyses to see if any domestic fauna occurred alongside this pre-ceramic Libyan cereals... at present, however, we have tantalizing prospect of an earlier, hitherto undetected diffusion of cereals to northern (Mediterranean) Libyan, presumably over land via the Nile Delta-- where equivalent evidence is likely buried under meters of alluvium. Such a scenario makes the delayed diffusion of cereals into Middle or Upper Egypt and the Nile Valley all the more striking. In this region the 'Primary Pastoral Community' (sensu Wengrow) seems indeed to have been rather averse to cereal farming.