utorak, 3. srpnja 2012.

Saharan dairying 7,000 years ago



Pottery shards put a date on Africa’s dairying
Yoghurt may have made it on to the menu for North Africans around 7,000 years ago, according to an analysis of pottery shards published today in Nature1.

The fermented dairy product left tell-tale traces of fat on the ceramic fragments, suggesting a way that the region’s inhabitants may have evolved to tolerate milk as adults.

The same team had previously identified the earliest evidence for dairying in potsherds nearly 9,000 years old from Anatolia2. But the findings from 7,000 years ago still predate the emergence and spread of the gene variants needed for the adult population to digest the lactose found in milk, says biomolecular archaeologist Richard Evershed of the University of Bristol, UK, who led the study with archaeological scientist Julie Dunne. He suggests that making yoghurt may have made dairy products more digestible.
Related: Earliest evidence for milk in the Near East and Southeastern Europe

Nature 486, 390–394 (21 June 2012) doi:10.1038/nature11186

First dairying in green Saharan Africa in the fifth millennium bc 

Julie Dunne et al.

In the prehistoric green Sahara of Holocene North Africa—in contrast to the Neolithic of Europe and Eurasia—a reliance on cattle, sheep and goats emerged as a stable and widespread way of life, long before the first evidence for domesticated plants or settled village farming communities1, 2, 3. The remarkable rock art found widely across the region depicts cattle herding among early Saharan pastoral groups, and includes rare scenes of milking; however, these images can rarely be reliably dated4. Although the faunal evidence provides further confirmation of the importance of cattle and other domesticates5, the scarcity of cattle bones makes it impossible to ascertain herd structures via kill-off patterns, thereby precluding interpretations of whether dairying was practiced. Because pottery production begins early in northern Africa6 the potential exists to investigate diet and subsistence practices using molecular and isotopic analyses of absorbed food residues7. This approach has been successful in determining the chronology of dairying beginning in the ‘Fertile Crescent’ of the Near East and its spread across Europe8, 9, 10, 11. Here we report the first unequivocal chemical evidence, based on the δ13C and Δ13C values of the major alkanoic acids of milk fat, for the adoption of dairying practices by prehistoric Saharan African people in the fifth millennium BC. Interpretations are supported by a new database of modern ruminant animal fats collected from Africa. These findings confirm the importance of ‘lifetime products’, such as milk, in early Saharan pastoralism, and provide an evolutionary context for the emergence of lactase persistence in Africa.

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