for National Geographic News
In 2007 scientists suggested that seafaring Polynesians and their chickens beat Columbus to the New World by a century.
A chicken bone found in Chile dating to A.D. 1320 to 1410—well before the explorer's arrival—and evidence of a genetic mutation linking that bone to chickens in Polynesia supported the theory. Since chickens weren't native to the Americas, they had to have arrived with human visitors.
But now the fossil has become a bone of contention in a new study, which contradicts the genetic evidence linking Chilean and Polynesian chickens.
A genetic comparison of chicken breeds from around the world reveal that modern-day Chilean chickens—which some scientists have argued carry Polynesian blood—are merely an offshoot of the common poultry found in restaurants and fast-food chains worldwide. In other words, the Chilean chicken could have come from anywhere.
"The Chilean chicken is a Kentucky Fried Chicken chicken, which is the ubiquitous chicken worldwide," said lead study author Alan Cooper of the Australian Center for Ancient DNA in Adelaide.
The new study is detailed in this week's issue of the Proceedings of the National Academy of Sciences.
The new findings contradict a study published last year, based on research led by Alice Storey of the University of Auckland in New Zealand and colleagues.
Using genetic and radiocarbon dating techniques, Storey's team had concluded that a chicken bone unearthed in Chile predates Columbus' arrival in the Americas by a century or more.
"We don't disprove that theory, but we don't find any evidence for it at all," Cooper told National Geographic News.
(Explore an time line of ancient human migration.)
Storey's team had reported that their ancient chicken bone carried a genetic mutation that linked it to chickens living on Pacific islands from the same time period.
In their new research, Cooper and his team show that the mutation is not unique to ancient Chilean or Polynesian chickens. Rather, it is present in modern Chilean chickens as well as in thousands of other chicken breeds living worldwide.
"The Chilean modern birds turn out to have standard European chicken DNA," Cooper said. "We found no evidence of them being having an unusual lineage."
(Get the facts on DNA.)
Storey conceded that the mutation her team found may not be unique.
"Initially we had recognized this mutation which we thought was unique to the Pacific," she said. "Their study suggests that's not true."
She added, however, that her team still stands by their original radiocarbon dating results and will publish new supporting evidence soon.
"We're absolutely confident with what we have," Storey said. "As long as the date stands, the genetics that they present really are irrelevant."
Terry Jones, an archaeologist at Cal Poly San Luis Obispo in California, was not involved in either study.
"I see a stalemate here," Jones said.
"I don't think this is the final word by any means. The burden of proof on this issue is extremely high. Neither study seems to have met it."
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