Using DNA to Track Potato Ancestors

The evolutionary origin of modern day potatoes has been the subject of debate among scientists. While some scientists hold that Chilean potatoes were the first to be planted in Europe, some believe that European potatoes generally descended from plants grown high in the Andean mountains between eastern Venezuela and Argentina. As the theory goes, the Andean potatoes were wiped out during the Great Irish potato famine of the mid 1800’s, initiating the import of Chilean varieties into the continent.

However, scientists from the University of Wisconsin in Madison say that both theories are wrong. By analyzing DNA samples of potato herbarium specimen, the group concluded that both the Andean and Chilean potato were grown simultaneously in Europe, decades before and after the great famine. Results of the analyses show that the Andean varieties grew as late as the early 1900s in the continent, together with the Chilean potatoes for several decades before the latter became dominant.

According to David Spooner, co-author of the paper, their work is the first to provide direct evidences on the evolution of potatoes, unlike the previous theories that rely mainly on inferences based on morphology of old plant samples and historical records of the Irish famine.

For more information read http://www.news.wisc.edu/14649. The paper published by the American Journal of Botany is available at http://www.amjbot.org/cgi/reprint/95/2/252.