Pigs Domestication Took Root in Many Places, Study Finds By Rosie Mestel(c) 2005, Los Angeles Times
Mean-tempered, big-tusked wild boars were transformed thousands of years ago into floppy-eared domestic pigs not once or twice, but repeatedly in many parts of the world as humans abandoned foraging and hunting for a settled farming life.
In a report published Friday in the journal Science, scientists used DNA from wild boars and pigs to conclude that pig domestication occurred in at least seven places through the millenniums.
The question is no longer where pigs were domesticated but where pigs were not domesticated, said Greger Larson, a Ph.D. student at the University of Oxford and the paper¹s first author.
The surprisingly widespread origin of domestic pigs about 9,000 year ago is unusual in the history of animal domestication. Sheep, cows, horses and goats were traditionally thought to have been domesticated just a handful of times during human farming history, mostly in the Fertile Crescent of the Near East.
Charles Darwin, among others, proposed that pigs were domesticated just twice -- in Asia and the Near East -- then transported by Neolithic migrants who carried their farming culture with them.
Larson and co-authors in Sweden, England and New Zealand extracted DNA from bones of wild boars and domestic pigs and scrutinized previously gathered genetic samples of pigs.
Comparing the structure of a tiny segment of DNA from 362 wild boars and 324 domestic pigs from 40 countries, they found that wild boars had distinct genetic sequences depending on where they originated.
The scientists then matched the DNA of the pigs to the boars. They concluded that pigs were domesticated in central Italy, India, Burma/Thailand, western Indonesia/New Guinea, in addition to the previously identified locations of the Near East and China.
The pig data add to emerging theories that the domestication of animals occurred multiple times in different places, said Jared Diamond, a professor of geography and physiology and a scholar of human civilizations.
There¹s now evidence not only for pigs but that cows were domesticated at last three times -- around the fertile crescent ... in India ... and North Africa, Diamond said.
The first steps in pig domestication were likely initiated by the boar. Boars that were less cautious and more friendly would venture close to human villages to root through trash.
These boars tended to maintain a more juvenile behavior compared with the aggressive and skittish demeanor of normal wild adults. Boars that exhibited this juvenile behavior got more food and were able to breed more. Over time, juvenile traits -- not only tameness, but also shorter snouts, smaller tusks and squealing -- became bred into early domesticated pigs.
Only later would pigs have been deliberately bred by human beings for traits such as extreme size and hairlessness, said Keith Dobney, a co-author of the study and an archaeologist at Britain¹s University of Durham.
The pig work provides a new tool for tracking movements of prehistoric humans, the authors said. By assessing the genes of local domestic pigs,researchers could learn where the animals¹ wild boar ancestors hailed from-- and thus uncover ancient trade routes and human migration paths.
Cats look down on you...Dogs look up to you...Pigs look you square in the eye.