PRECOLUMBIAN INTRODUCTION OF CHICKENS TO
THE AMERICAS FROM POLYNESIA
© The Vancouver Sun, Tuesday, June 05, 2007
WASHINGTON -- A chicken bone found in Chile provides solid evidence to settle a debate over whether Polynesians traveling on rafts visited South America thousands of years ago -- or vice versa, researchers said Monday.
The DNA in the bone carries a rare mutation that links it to chickens in Tonga and Samoa, and radiocarbon dating shows it is around 600 years old -- meaning it predates the arrival of Spanish conquerors in South America.
"These chickens are related to hens from Polynesia,'' said Alice Storey, a doctoral student at the University of Auckland in New Zealand, who worked on the study.
Her team's finding, published in the Proceedings of the National Academy of Sciences, suggests that best-selling author and adventurer Thor Heyerdahl was only partly right when he sailed on the raft Kon-Tiki from South America to Polynesia to prove prehistoric contact across the Pacific.
"He had it backwards," Storey said in a telephone interview.
"Heyerdahl had proposed that people were coming out of South America and into Polynesia," she added.
"We know the Polynesians were actually going to South America and probably trading chickens for [sweet potatoes] and bottle gourds."
Chickens originally come from Southeast Asia, and many researchers had assumed that Spanish conquistadors carried them there in the 16th century.
Other experts were not sure, and when a team stumbled on some old chicken bones at an archeological site in Chile, they decided to carbon-date them and look at the DNA.
Luckily for the researchers, the chicken DNA carries a rare mutation.
It is identical to bones from two prehistoric archeological sites in the Pacific: Mele Havea in Tonga, dating to 2,000 years ago, and one from American Samoa, about the same age as the Chilean site.
"Argument about the origins and date of introduction of the domestic fowl or chicken [Gallus gallus] to the Americas has raged for over 30 years," Storey's team wrote.
"Here, we provide the first unequivocal evidence for a pre-European introduction of chickens to South America and indicate, through ancient DNA evidence, that the likely source of that introduction was Polynesia," they added.