January 21, 2013

Sweet potato genome provides link between South America and Polynesia

The actual PNAS paper seems to be still under embargo, but here's a news story in Science about the new research:

By analyzing genetic markers specific to sweet potatoes in both modern samples of the plant and older herbarium specimens, the researchers discovered significant differences between varieties found in the western Pacific versus the eastern Pacific. This finding supports the so-called tripartite hypothesis, which argues that the sweet potato was introduced to the region three times: first through premodern contact between Polynesia and South America, then by Spanish traders sailing west from Mexico, and Portuguese traders coming east from the Caribbean. The Spanish and Portuguese varieties ended up in the western Pacific, while the older South American variety dominated in the east, which would explain the genetic differences the French team saw.
Apart from the famous Heyerdahl voyage (which has recently become the subject of a 2012 movie), there was some other research regarding the introduction of Polynesian chickens to Chile. I have not followed the genetics of that part of the world very closely, but it's my impression that such a link between Polynesia and South America has not been found in the human populations of the two regions.

6 comments:

andrew said...

In a nutshell, the genetic data confirms prior conclusions reached via linguistics, geography and visual plant taxonomy. It is a good and useful thing to confirm old results via a new methodology, but it is not a paradigm shifting result.

Ponto said...

The Colonial period in Polynesia especially of Easter Island, the enslavement and transportation of the Easter Island Polynesians to South America with some introduction of European and South American flora, fauna and humans to Easter Island may have blurred the issue. I am sure there are many Africans whose staple is Maize who have no knowledge that Maize is not indigenous to Africa.

Maybe the Maori colonization of New Zealand with their plant and animal introductions could illuminate the issue of Sweet Potatoes in Polynesia. The Kumara is a Sweet Potato.

Thor Heyerdahl was just a petty racist Norwegian of little intellectual ability, and not worthy of further discussion.

eurologist said...

I have not followed the genetics of that part of the world very closely, but it's my impression that such a link between Polynesia and South America has not been found in the human populations of the two regions.

Same here - but the other evidence is accumulating strongly.

terryt said...

"In a nutshell, the genetic data confirms prior conclusions reached via linguistics, geography and visual plant taxonomy".

Yes. To me the most interesting part is:

"This finding supports the so-called tripartite hypothesis, which argues that the sweet potato was introduced to the region three times: first through premodern contact between Polynesia and South America, then by Spanish traders sailing west from Mexico, and Portuguese traders coming east from the Caribbean".

Not a single entry for the kumara.

"it's my impression that such a link between Polynesia and South America has not been found in the human populations of the two regions".

Exactly correct. However other evidence does indicate contatct, and don't forget that any Polynesians arriving in America would be greatly outnumbered by the earlier inhabitants so any haplogroups that remained behind would be rapidly drifted out. Some Polynesians must have made the return trip back into the Pacific for the kumara to have made it. It's is hardly surprising that Polynesians would have made landfall in America. They covered all the Pacific Ocean islands.

batman said...

There's already some obvious connections existing between S-America and Polynesia - given by the genetic co-relation of domestic chicken, potato and bottle gourd, repsectively.

Recently a closer connection is found between the indians of South-America and the Polyneisans as well - sharing two specific HLA-types.

http://onlinelibrary.wiley.com/doi/10.1111/j.1399-0039.2006.00717.x/abstract;jsessionid=A8E412EB12C6A119816EBF20F66FB445.d01t01

The void oceanic travels that the famous humanitarian and outstanding scientist, Dr. Thor Heyerdahl, postulted in his thesis as of 1942 - have finally proven to be rigth.

Recently some plain and irrefutable facts from recent archaeolgy and anthropology have proven his general thesis of ancient ocean voyages around the Pacific.

http://www.nature.com/news/2007/070924/full/news070924-9.html

Concerning Polyneisan contact with S-Amerika specifically the question now is if the old boat-culture of Peru set sail for the islands in the ocean - or was if it was the Polynesians that followed the winds to south America? Or both?

"Beyond Kon-Tiki":
http://www.sciencemag.org/content/328/5984/1344.summary

terryt said...

"The void oceanic travels that the famous humanitarian and outstanding scientist, Dr. Thor Heyerdahl, postulted in his thesis as of 1942 - have finally proven to be rigth".

No. The movement through the Pacific was from west to east. No movement seems to have 'started' in America.

Rather elements of American technologies were picked up by wandering Polynesians from the Central Pacific and then carried back to their homelands.

"Recently some plain and irrefutable facts from recent archaeolgy and anthropology have proven his general thesis of ancient ocean voyages around the Pacific".

No-one has ever disputed 'ancient ocean voyages around the Pacific'. Thor suggested these voyages had started from America. None seriously consider that to be so today.

"specifically the question now is if the old boat-culture of Peru set sail for the islands in the ocean"

One thing Thor Heyerdal did prove is that nobody would make a return voyage in the sort of boat he used. However many have shown since that Polynesian navigation and sailing techniques were easily adequate for wide-ranging voyaging.