|15 October 2006
Goats key to spread of farming, gene study suggests
Goats accompanied the earliest farmers into Europe some 7,500 years ago, helping to revolutionize Stone Age society, a new study suggests. The trailblazing farm animals were hardy and highly mobile traveling companions to ancient pioneers from the Middle East who introduced agriculture to Europe and elsewhere, researchers say.
The onset of farming ushered in the so-called Neolithic Revolution, when settled communities gradually replaced nomadic tribes and their hunter-gatherer lifestyles between 8000 and 6000 BCE. A team of archaeologists and biologists has traced the origins of domesticated goats in Western Europe to the Middle East at the beginnings of the Neolithic period. The study is based on DNA analysis of goat bones from a cave in France and suggests the animals spread across Europe quickly after their introduction. The team says its findings indicate that goats may have played a key role in the rise and spread of farming worldwide.
The new research follows up on a 2001 study by the same team that found domesticated goats today are much more mixed genetically than other livestock. By tracing the animals' mitochondrial DNA, which is passed down in cells through generations from mother to offspring, scientists showed that goats differ much less genetically between continents than cattle, sheep, or pigs. This suggested that goats were transported much more extensively in the past, allowing the genetic material from different populations to intermingle. The 2001 study also traced the main origins of domesticated goats to the Near and Middle East regions.
DNA analysis of 7,000-year-old goat bones from caves in Baume d'Oullen in southwestern France revealed high genetic diversity and two goat lineages stemming from the Near East. The researchers say that this indicates genetic mixing in goats occurred with the first waves of Neolithic farmers in Europe around 7,500 years ago. Goats would have provided clothing, meat, and milk as well as bone, sinew, and dung for consumption and trade, the study team says. Once these pioneer farmers decided to settle, Taberlet adds, they likely took sheep and cows from the surrounding area.
Peter Bogucki, an expert on Europe's early farming societies at Princeton University in New Jersey, says the work is an excellent example of how recent advances in the study of genetic material from animal bones can shed light on prehistoric human activity. Bogucki adds that early Neolithic peoples from the Mediterranean region "were quite adept at coastal movement by watercraft and at crossing straits, even venturing across open sea." Archaeologist Marek Zvelebil, from the University of Sheffield in England, cautions that the research is based on only a small sample of bones from a single site. "This site is, however, strategically located along one of those major routes for the dispersal of farming into Europe," Zvelebil said. He says the study backs other archaeological evidence that indicates that once Neolithic culture reached modern-day Italy, it spread rapidly through the western Mediterranean region. "The goat was perhaps the first domestic animal, going back to about 11,000 to 12,000 years ago to the Zagros Mountains in northwest Iran," the archeologist added. Yet, he says, the study does not necessarily provide evidence of large-scale migration from east to west by Neolithic colonizers.
Source: National Geographic News (10 October 2006)
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