Potatoes originated in PeruAsian News InternationalWashington, October 5,2005

Where did the potatoes, that you relish almost everyday in some form or the other, originate? Don't know the answer? Well, no one did, until recently, when a new study published in the Proceedings of the National Academies of Sciences revealed that the international dietary staple originated in Peru.

Humans have cultivated potatoes for long, but there had been a great controversy about its origin. A team led by a USDA potato taxonomist stationed at the University of Wisconsin-Madison, has for the first time demonstrated a single origin in southern Peru for the cultivated potato.

The scientists analyzed DNA markers in 261 wild and 98 cultivated potato varieties to assess whether the domestic potato arose from a single wild progenitor or whether it arose multiple times.

"In contrast to all prior hypotheses of multiple origins of the cultivated potato, we have identified a single origin from a broad area of southern Peru. The multiple-origins theory was based in part on the broad distribution of potatoes from north to south across many different habitats, through morphological resemblance of different wild species to cultivated species, and through other data. Our DNA data, however, shows that in fact all cultivated potatoes can be traced back to a single origin in southern Peru," said David Spooner, the USDA research scientist who led the study. The earliest archaeological evidence suggests that potatoes were domesticated from wild relatives by indigenous agriculturalists more than 7,000 years ago.

"When researchers discover an important trait - for example, that a certain species is resistant to disease then everything related to that species becomes potentially useful. We can screen samples to see if related germplasm has similar resistance, in which case we may be able to guide plant breeders to germplasm to use in breeding programs," Spooner said.
And beyond the agricultural benefits, Spooner's study has helped to rewrite a small but important chapter of evolutionary history.

"Books are written about questions of how crops originate. Sometimes statements are repeated so often that they are accepted as fact. This is a way to get people to reconsider long-held assumptions of the origin of the potato, and stimulate us to reconsider the origins of other crops using new methods," he said.