Abstract Detail

Charles Heiser Special Contributed Paper Session

Clarke, Andrew C. [1], Holland, Barbara R. [2], McLenachan, Patricia A. [3], Nakatani, Makoto [4], Matthews, Peter J. [5], Green, Roger C. [6], Penny, David [3].

Evidence for prehistoric human contact between Polynesia and South America: DNA analysis of the sweet potato (Ipomoea batatas).

The origins of the sweet potato (Ipomoea batatas), a crop species fundamental to many agricultural systems in pre-European Polynesia, has been of long-standing scientific interest. The sweet potato, probably along with the bottle gourd, is thought to have arrived in the Pacific from South America. Various lines of botanical, archaeological, linguistic and genetic evidence are consistent with this transfer being effected by Polynesian voyagers who collected the sweet potato from South America between AD 1000 and 1200. The strongest evidence for contact is the Polynesian word kumara, which appears to be derived from the Ecuadorian cumar. Despite growing acceptance of this human-mediated transfer, there remain a number of unresolved questions about the sweet potato in Oceania, including: 1) the point on the South American coast where Polynesians made landfall, 2) the number of Polynesian lineages introduced into the Pacific, 3) the dispersal routes of sweet potato within Polynesia, and 4) the influence of Spanish (camote) and Portuguese (batata) introductions of sweet potato in the western Pacific. To address these questions we have used the amplified fragment length polymorphism (AFLP) fingerprinting technique to genotype 270 unique accessions of sweet potato from Asia, Island Melanesia, Polynesia and the Americas. AFLP data have been used to construct phylogenetic trees, and to improve phylogenetic resolution we have developed a new method to optimise AFLP scoring parameters. A putative kumara lineage, representing a prehistoric, Polynesian-mediated introduction from South America, has been identified. Sweet potato accessions from Asia to Western Polynesia were found to be genetically diverse, and the relationships between them are complex. The phylogenetic positions of the New Zealand Maori varieties raises questions about their presumed close relationships with other lineages in Eastern Polynesia. Together, these findings suggest a much more complex picture of sweet potato dispersal in Oceania than is currently recognised.

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1 - University of Otago, Department of Anatomy and Structural Biology, PO Box 913, Dunedin, 9054, New Zealand
2 - University of Tasmania, School of Mathematics and Physics, Private Bag 37, Hobart, TAS, 7001, Australia
3 - Massey University, Institute of Molecular BioSciences, Private Bag 11222, Palmerston North, 4442, New Zealand
4 - National Institute of Crop Science, Department of Field Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan
5 - National Museum of Ethnology, Department of Social Research, Senri Expo Park, Suita City, Osaka, 565-8511, Japan
6 - University of Auckland, Department of Anthropology, Private Bag 92019, Victoria Street West, Auckland, 1142, New Zealand

Keywords:
AFLP
sweet potato
Ipomoea batatas
Polynesia
crop dispersal.

Presentation Type: Oral Paper:Papers for Topics
Session: 15
Location: Lindell D/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 2:00 PM
Number: 15003
Abstract ID:750