March 28, 2012
DNA Traces Cattle Back To Ancient Times
A new genetic study confirms that modern domesticated cattle are descended from 80 domesticated wild oxen in the Near East over 10,500 years ago.
Scientists from CNRS, the National Museum of Natural History in France, the University of Mainz in Germany, and University College London (UCL) in the UK performed the study by extracting DNA from the bones of extracted domestic cattle found in Iran. These sites are believed to date back to the invention of farming and the area where cattle first became domesticated.The international team of scientists found only small differences in the DNA from the Iranian excavation and modern day domestic cattle. What little difference there is, say the scientists, could come from different population histories. By analyzing the DNA with computer simulations, they believe the differences in DNA could only have arisen if a small number of animals were domesticated from the wild ox. They believe as few as 80 wild oxen are responsible for what we know now as modern, domestic cattle.
Results of this study are published in the current issue of the journal Molecular Biology and Evolution.
In a press release announcing the results, Dr Ruth Bollongino of CNRS, France, and the University of Mainz, Germany; lead author of the study, said, “Getting reliable DNA sequences from remains found in cold environments is routine. That is why mammoths were one of the first extinct species to have their DNA read. But getting reliable DNA from bones found in hot regions is much more difficult because temperature is so critical for DNA survival. This meant we had to be extremely careful that we did not end up reading contaminating DNA sequences from living, or only recently dead cattle.”
According to the scientists, it is important to the archeological study of domestication to note the number of original animals.
Prof Mark Thomas, geneticist and an author of the study based at the UCL Research Department of Genetics, Evolution and Environment: “This is a surprisingly small number of cattle. We know from archaeological remains that the wild ancestors of modern-day cattle, known as aurochs, were common throughout Asia and Europe, so there would have been plenty of opportunities to capture and domesticate them.”
Based at the University of Mainz, Germany, Professor Joachim Burger had this to say about the wild ox, “Wild aurochs are very different beasts from modern domestic cattle. They were much bigger than modern cattle, and wouldn´t have had the domestic traits we see today, such as docility. So capturing these animals in the first place would not have been easy, and even if some people did manage snare them alive, their continued management and breeding would still have presented considerable challenges until they had been bred for smaller size and more docile behavior.”
Other archeological studies have shown other animals, not just cattle, were domesticated. Goats, sheep, and pigs have also been found to be domesticated in the Near East around the beginning of the farming age. It is much harder, however, to determine how many of these animals were domesticated. While traditional archeological techniques do not provide an entire picture as to how many animals were domesticated, genetic research helps to fill in these gaps.
Dr Marjan Mashkour, a CNRS Archaeologist working in the Middle East added “This study highlights how important it can be to consider archaeological remains from less well-studied regions, such as Iran. Without our Iranian data it would have been very difficult to draw our conclusions, even though they concern cattle at a global scale”.