Retracing the path of the chicken across the Pacific

Transcript

Archaeologists from Australia's Adelaide University believe they may have cracked the answer to the question of how the chicken crossed the vast expanse of the Pacific.

Earlier genetic studies had suggested chickens were probably brought to Polynesia by travellers from South America, but this latest study, using DNA samples from ancient and modern bone samples, may put this theory to rest.

One of the researchers, Dr Vicki Thomson, told Jamie Tahana the Pacific chicken is genetically unique and the findings will allow scientists to reconstruct the migratory patterns of their human carriers over a thousand years ago.

VICKI THOMSON: We've found a unique signature in Polynesian chickens, that seems to define them and the grouping of ancient chickens that were taken into the Pacific by the Lapita. We've used this to reconstruct migration routes across the Pacific and based on chicken evidence, it doesn't look like there has been contact with South America.

JAMIE TAHANA: So that basically puts to rest that claim that Polynesians may have reached South America?

VT: We just believe that there isn't any evidence based on the chickens so far. So new evidence may arise, but based on what we've got so far from the chickens, it doesn't look like it, no.

JT: Why chickens?

VT: Well there's actually a reasonable level of diversity in the mitochondrial control region of chickens worldwide, and there's actually quite a lot of archaeological remains in the Pacific, so it made it a good species to look at.

JT: So they would have presumably been brought with the first migratory humans would they?

VT: We think so, yes. We can't actually be sure that the first boats that set out had them, but at least some of the early migrations definitely, probably would have had them.

JT: And what is the migratory pattern? What's the route they took?

VT: There's different theories about that. There's some theories that Micronesia was settled first, and that may be from the Philippines or Indonesia. But then Western Polynesia and the movement into Eastern Polynesia came a little later.

JT: What was the process here? Is it basically going to each island, doing the research and then piecing together a kind of jigsaw? Or is it more intricate than that?

VT: Yeah, we deal with a lot of archaeologists on different islands, so we rely on them excavating the bones and then passing them along to us to actually analyse. But yeah, it is very much like piecing together a jigsaw puzzle.

JT: Does this also say stuff about the Pacific chicken, can we call it?

VT: Yeah, so we're actually hoping to be able to use this unique signature I was talking about before that certain Polynesian chickens have in the modern populations and look at their nuclear DNA and see if we can compare that to you know, highly-domesticated chickens and see what genes might be involved in the selection of the breeds that became our domestic chickens.

JT: Is that basically a way of looking at the evolution of the chicken?

VT: Yeah, the evolution of the domestic chicken, you know, what things have been selected for and therefore in the Polynesian chicken we don't see that selection sign.