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.