Elevated genetic risk for multiple sclerosis emerged in steppe pastoralist populations by Barrie, W, Yang, Y, Irving-Pease, EK, Attfield, KE, Scorrano, G, Jensen, LT, Armen, AP, Dimopoulos, EA, Stern, A, Refoyo-Martinez, A, Pearson, A, Ramsøe, A, Gaunitz, C, Demeter, F, Jørkov, MLS, Møller, SB, Springborg, B, Klassen, L, Hyldgård, IM, Wickmann, N, Vinner, L, Korneliussen, TS, Allentoft, ME, Sikora, M, Kristiansen, K, Rodriguez, S, Nielsen, R, Iversen, AKN, Lawson, DJ, Fugger, L, Willerslev, E