The DNA of a 150-year-old potato has forced scientists and historians to re-examine the commonly held theory about the origin of the infamous Irish potato famine. During the 1840s, more than one million people starved and another two million emigrated to America when Ireland's potato crop was devastated. Contemporary clerics blamed the disaster on the devil, but in 1846 a scientific theory expounded by the Reverend Miles Berkeley gradually became widely held as the predominant reason for the famine. Berkeley blamed a fungus for infecting the crop, making lesions appear on leaves and stems until the potatoes rot and become inedible.