Genomic Evidence of Widespread Admixture from Polar Bears into Brown Bears during the Last Ice Age

James A. Cahill, Peter D. Heintzman, Kelley Harris, Matthew D. Teasdale, Joshua Kapp, Andre E.R. Soares, Ian Stirling, Daniel G. Bradley, Ceiridwen J. Edwards, Kiley Graim, Aliaksandr A. Kisleika, Alexander V. Malev, Nigel Monaghan, Richard E. Green, Beth Shapiro