Nibbles: Asses, Mapping pathogens, Oysters, Tea, Turkish biodiversity hotspot, Dolmades and sage, Yams festival, Pollen video, Agriculture and mitigation, Rarity, School feeding, Sheep

Nibbles: Rice conservation and use, Tunisian genebank, Buno, Popcorn, Sustainability, Brazilian social networking, Strawberry breeding, Sunflower genomics, Climate change and fisheries

Measuring diversity in Tibetan walnuts

You collect leaves from 220 walnut trees of two morphologically very distinct species (Juglans regia and J. sigillata) from two unrelated groups of families of villagers in each of six different villages in Tibet. You get the gene-jockeys to do their microsatellite stuff on the leaves. You calculate the contribution of species, of the kin relationship of the growers and of village to genetic diversity. You expect the biggest genetic differences to be between species.

You are wrong.

Yes, the “species,” which look totally different, are in fact indistinguishable genetically. But there were significant differences among villages, and smaller but still significant differences between unrelated families of farmers within villages. So, you might be particularly interested in certain traits, for improvement say (and so are the farmers: walnut landraces in this part of Tibet are often named after fruit phenotypes). But — in this case — morphology is not a great guide to the totality of the underlying genetic diversity. So you can’t use it alone for conservation.

Which is also the conclusion researchers in Benin arrived at in their study of another tree, akee (Blighia sapida), also just out. A conservation and use (domestication, in this case) strategy “should target not only the morphotypes recognized by local populations but should also integrate the population genetics information.”

Does this amount to a general rule?

Nibbles: Fungi, Dogs, Protected areas, Banana, Ethiopia, Haiti

Documenting the farming transition around the world

Two recent papers shed light on that grey area where hunter-gatherers become farmers. From northern China, archaeological evidence is showing that 8,000 years ago it was highly mobile foraging bands interested in feeding not only themselves but also, interestingly, their hunting dogs, who in effect invented millet — that’s broomcorn millet (Panicum miliaceum) and foxtail millet (Setaria italica) — cultivation. This was later taken up and intensified by what are known as the Late Banpo Phase millet agriculturalists.

A thousand years previously, and half a world away, archaeological, paleoecological, linguistic and genetic data from the SW United States seems to suggest that “maize moved northward from central Mexico to [the] Southwest by being passed from one hunter-gatherer band to the next, who incorporated the crop into their subsistence economies and eventually became farmers themselves.” Not, that is, as a result of the movement of Mexican agriculturalists, which was the alternative scenario. Nothing to do with feeding their livestock in this case, though. Turkeys seem to have been domesticated much later.