...Prof. Haak will also try to detect more plague DNA in hundreds of skeletons from the late Neolithic and early Bronze Age. So far, DNA evidence from a dozen skeletons points to little variability between the strains of Yersinia pestis in such remains, suggesting that the pestilence spread rapidly across the continent. The speed may owe to another human advance at this time -- the domestication of wild horses, which may literally have carried the disease into Europe. "We see the change from wild local horses to domesticated horses, which happened rapidly at the beginning of the Bronze Age," said...