Monday, July 28, 2008

Polynesian chickens in Chile? New furor, but they still look Polynesian.

A towering scientific furor has arisen over...chickens.

Specifically, whether Polynesian voyagers introduced chickens to South America before the first Europeans showed up...carrying their own chickens.

(Image: Red jungle fowl, the chicken of the Polynesians--in this case, a rooster. Credit: U.S. Fish and Wildlife Service.)

We'll get into some detail later, but the short version is this:

It still looks clear that voyaging canoes from the Polynesian culture of the Pacific carried chickens to the Americas well before Christopher Columbus, despite a great deal of rancorous comment and competing scientific papers in the esteemed journal, Proceedings of the National Academy of Scientists (PNAS).

Here's the longer version.

In 2007, researchers led by Alice Storey of New Zealand published a paper on the dating and DNA analysis of chicken bones found at the El Arenal archaeological site in southern Chile.

They found that 1) the bones dated to before Europeans first arrived in the Americas, and 2) the chickens were closely related genetically to early chickens found in Hawai'i and elsewhere in the Polynesian Pacific.

The inescapable conclusion was that the El Arenal chickens came from Polynesia, and since Polynesians, not South Americans, were a voyaging culture, that those chickens arrived on Polynesian voyaging canoes.

This helps resolve a couple of great anthropological mysteries.

  1. How could the amazing Polynesian voyaging culture have populated virtually every isolated island in the vast Pacific and missed the Americas? Answer, of course: It didn't. The Polynesians simply failed to settle in the Americas, perhaps because there were
    already people there.

  2. Throughout Polynesia, there are sweet potatoes. Sweet potatoes come from the Americas. How did they get into the Pacific? There have been suggestions, such as Thor Heyerdahl's drift raft theory, that somehow South Americans carried the potato through the Pacific. But it seems much more likely that voyaging canoes from the Pacific touched on the coast of South America and either did some swapping or some inspired botanical exploration.

Storey's paper was published in the PNAS in mid-2007. The same journal this week (July 28, 2008) published another chicken paper that challenges the Storey results. It is: “Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA,” by Jaime Gongora, Nicolas J. Rawlence, Victor A. Mobegi, Han Jianlin, Jose A. Alcalde, Jose T. Matus, Olivier Hanotte, Chris Moran, Jeremy J. Austin, Sean Ulm, Atholl J. Anderson, Greger Larson, and Alan Cooper.

In this one, Australian researcher Jaime Gongora argued that it might be premature to attribute those El Arenal chickens to a Polynesian voyager's introduction, in part because Gongora's team can't find Polynesian chicken DNA in modern South American chickens. Also because they argue it's possible the pre-European dates for the chicken bones were wrong.

Before we proceed further, a little chicken background. Chickens originated in Southeast Asia, and were so wildly popular as domestic fowl that they were carried around the world. Some went west to Europe, and some went east into Polynesia. They certainly got to the Americas from Europe, and the Storey work shows they may also have reached the Americas from Polynesia.

Gongora, in an emailed statement on his paper, said this:

“European chickens were introduced into the American continents by the Spanish after their arrival in the 15th century. However, there is ongoing debate about the presence of pre-Columbian chickens among Amerindians in South America, particularly in relation to Chilean breeds. This debate includes controversial claims that Polynesians introduced chickens into South America before the arrival of Europeans.”

Gongora said he conducted extensive surveys of the genetics of modern South American chickens, and found that they appear to be exclusively European in origin.

“This DNA study shows that modern Chilean chickens originated from European breeds, and the apparently pre-Columbian specimen provides no support for a Polynesian introduction of chickens to South America,” Gongora wrote.

He goes on to challenge the radiocarbon dates of the El Arenal site, suggesting that marine sediments might have contaminated them and made them seem older than they are.

“Definitive proof of Polynesian chicken introductions into the Americas will require further analyses of ancient DNA sequences and radiocarbon and stable isotope data from archaeological excavations within both Chile and Polynesia,” he wrote.

Anthropologist Elizabeth Matisoo-Smith, a co-author with Storey on the original paper, said their continued research has confirmed the original dates. They have already published work that shows that the diet of the El Arenal chickens was a land-based, not a marine-based diet.

“The Carbon and Nitrogen values show that the diet of the El Arenal chicken was terrestrial,” Matisoo-Smith said in an email.

“All the dates we have are consistent,” she said. The Storey and Matisoo-Smith team is in the process of getting its latest findings published.

The upshot of all this seems to be that, on balance, there is now more rather than less evidence of Polynesian chickens in Chile, and therefore Polynesian voyaging to the Americas.

© 2008 Jan W. TenBruggencate

1 comment:

Anonymous said...

It has not been demonstrated how the mtDNA of the South American chickens differ from that of the Indonesian/Polynesian races. This will need to be clarified before the claim can be made that the South American chickens mtDNA matches that of the Indo-European. It has also not been demonstrated what the nuclear DNA is saying. It should be made clear here that while Gallus gallus, the Burmese Red Junglefowl is the matriarchal ancestor of the vast majority of living domestic breeds, the Indonesian Red Junglefowl, Gallus bankiva was the matriarchal ancestor of a tiny percentage of archaic breeds. Those remote Indonesian and Oceania islands tend to be inhabited by feral populations of junglefowl introduced by human beings.
The first junglefowl to be domesticated was actually the Indonesian Red which gave rise to the game fowl. While the Indonesian Red Junglefowl is not the matriarchal ancestor of most extent
fighting game breeds, its Nuclear DNA is clearly present in most. In other words, male Indonesian Red Junglefowl contributed their genes even if females of the same species did not.

Secondly, two other much more unusual junglefowl species were the male ancestors of special ceremonial roosters which were highly valued by chiefs and other high-ranking individuals who carried these hybrids with them to remote archipelagos like Easter Island, Rapa, Ponape and Marquesis.

These cultures may have been attempting to escape genocide or ethnocide by larger more powerful ( Lapita) cultures which would arrive on the scene a bit later than the earlier Proto-Australoid/Melanesian/Micronesian sea farers.

The more remote the island, the higher likelihood only a very small percentage of founders ever arrived on the island, and the unusual mixture of hybrid genes along the father lines and not the mothers, evidentially resulted in some interesting mutations and phenotypey.

For example, the so-called Araucanian hens produce blue egg shells. No wild junglefowl produce tinted eggs, save for the Green Junglefowl which is the male ancestor of the archaic seafaring breed the Ayam bekisar or Long Crowing/ Singing Sea Fowl.

The nuclear DNA of Gallus varius is present in South American and Easter Island races but absent in Mainland Asia and Europe.