Irish Potato Famine Pathogen Origin Traced to South America

Using some ancient DNA detective work, a new study led by Mike Martin, University of California Berkeley postdoctoral researcher, and Tom Gilbert, professor at University of Copenhagen, has linked the culprit behind the 19th century Irish potato famine, which was transported to Europe in the 1840s, to a fungus-like organism that originated in South America. Just how the pathogen, called Phytophthora infestans, made the transatlantic leap to destroy potato crops on a global scale is a “Guns, Germs, and Steel”-like tale of New World exploration and devastation published in the advanced online edition of Molecular Biology and Evolution. The authors used genome sequences from 71 modern and historical samples of the microbial pathogen, a unique collection culled from worldwide private archives, to construct the ancestral tree of the pathogen. The origin of the species dates back to 1558 AD, the age when the first Europeans explored South America. More