Format: ORAL

JULIA M.KREINER 1,SERGIO M.LATORRE2 ,HERNN A.BURBANO2 ,JOHN R.STINCHCOMBE 3,SARAH P.OTTO4 ,DETLEFWEIGEL5 , ANDSTEPHEN I.WRIGHT3

1 Department of Ecology and Evolution, University of Chicago, Chicago, USA 2 Centrefor Life’s Origins and Evolution, University College London London, UK 3 Department of Ecology and Evolutionary Biology, University of Toronto Toronto Canada 4 Department of Zoology, University of British Columbia Vancouver, Canada 5 Max Planck Institute for Biology, Tübigen Germany

North America has experienced a massive increase in cropland use since 1800, accompanied more recently by the intensification of agricultural practices. Through genome analysis of present-day and historical samples spanning environments over the past two centuries, we studied the effect of these changes in farming on the extent and tempo of evolution across the native range of the common waterhemp (Amaranthus tuberculatus), a now pervasive agricultural weed. Modern agriculture has imposed strengths of selection rarely observed in the wild, with notable shifts in allele frequency trajectories since agricultural intensification in the 1960s. An evolutionary response to this extreme selection was facilitated by a concurrent human-mediated range shift. By reshaping genome-wide diversity across the landscape, agriculture has driven the success of this weed in the 21st century.