<p> Electronic Supplementary Materials Online Resource 1. Sampling year, month, and agency for genetic samples from North Slope caribou and reindeer herds. </p><p>Sampling Sampling Herd Name # DNA samples Sampling Agency Year (n) Month CARIBOU Porcupine (PCH) 61 1988 (7) June Yukon Govt; USFWS 2004 (10) March 2008 (19) March 2009 (25) March Central Arctic (CAH) 66 1998 (16) June ADF&G 2000 (4) June 2001 (9) July 2008 (16) July 2009 (10) April 2009 (3) June 2010 (10) April Teshekpuk Lake 52 2008 (36) June NSB; ADF&G (TCH) 2009 (16) June Western Arctic 67 2008 Sept. ADF&G (WAH) REINDEER Ongtowasruk from 43 2009 (34) July Mager, K.; UAF Wales, Alaska (ONG) 2010 (9) July Reindeer Research Program Davis from Nome, 13 2010 July UAF Reindeer Research Alaska (DAV) Program Kodiak Island feral 8 2004 (2) ADF&G reindeer (KOD) 2006 (3) unknown 2007 (3) Hunter-caught feral 3 2009 winter Dickie Moto, reindeer Kotzebue/Deering, AK Online Resource 2. For each locus in each population: Number of Alleles (A), Allelic Richness (AR), and Expected Heterozygosity (He). </p><p>TE RT Ohe NVHRT3 RT2 FCB19 BM650 BM451 RT9lon RT2 RT1 BMS XA BL4 BMS178 Pop n 6 D OheQ 0 7 RT1 3 6 3 g RT7 4 0 RT30 745 N4 C89 2 8 Mean SPR 59 A 11 10 17 9 12 11 10 12 14 11 10 8 11 13 5 4 10 14 13 10.789 D 5.7 4.86 5.88 3.45 4.83 7.66 AR 33 7 6.809 5.109 6.013 6.536 4.991 4.922 7.303 6.449 5.101 0 6.045 6.030 4.115 8 6 9 6.448 5.701 0.7 0.72 0.83 0.63 0.72 0.88 He 87 9 0.835 0.733 0.744 0.845 0.744 0.744 0.875 0.841 0.765 4 0.804 0.777 0.733 7 9 8 0.792 0.781 KOD 8 A 4 3 3 4 2 3 3 5 4 4 4 4 3 4 4 3 3 8 3 3.737 3.9 2.98 3.98 2.98 2.98 7.59 AR 92 3 2.875 3.742 2.000 3.000 2.992 4.867 3.875 3.875 3.875 3 2.983 3.875 4.000 3 3 2 2.992 3.656 0.7 0.42 0.72 0.43 0.42 0.88 He 68 9 0.589 0.446 0.518 0.488 0.598 0.813 0.723 0.759 0.732 3 0.429 0.679 0.774 8 9 4 0.500 0.617 WAH 67 A 13 14 20 10 14 14 14 15 17 13 8 18 8 15 7 4 14 16 12 12.947 7.0 7.88 8.14 3.23 7.88 8.33 AR 03 0 8.434 6.935 8.225 7.800 7.454 7.252 8.184 7.425 5.405 8 6.372 7.333 5.277 5 0 0 7.237 7.148 0.8 0.88 0.89 0.60 0.88 0.90 He 67 8 0.907 0.859 0.905 0.887 0.870 0.867 0.904 0.879 0.781 1 0.857 0.874 0.810 0 8 6 0.876 0.859 TCH 52 A 12 13 19 13 14 15 12 13 13 13 9 16 12 16 7 4 13 15 13 12.737 7.0 6.96 8.17 3.61 6.96 8.09 AR 50 3 8.795 6.930 7.809 8.396 6.828 7.003 8.053 6.926 5.285 2 6.772 7.968 5.154 2 3 0 7.938 7.090 0.8 0.84 0.89 0.67 0.84 0.90 He 73 2 0.918 0.861 0.879 0.910 0.836 0.841 0.908 0.848 0.777 5 0.852 0.893 0.789 8 2 4 0.905 0.855 CAH 66 A 14 16 20 14 16 14 12 16 14 12 10 16 12 14 7 4 16 21 13 13.737 7.2 7.32 7.31 3.45 7.32 9.09 AR 67 2 8.002 7.307 7.652 8.257 7.048 7.701 8.438 7.307 5.593 7 6.809 7.378 4.999 2 4 7 7.652 7.154 0.8 0.85 0.86 0.64 0.85 0.92 He 76 6 0.896 0.862 0.881 0.904 0.866 0.869 0.913 0.869 0.773 4 0.862 0.880 0.771 9 7 6 0.893 0.856 PCH 61 A 13 15 19 11 13 14 12 16 17 14 10 17 11 14 7 4 15 17 11 13.158 7.0 7.86 7.95 3.25 7.86 8.42 AR 30 1 7.620 6.973 7.733 8.366 7.680 7.347 8.644 7.370 5.294 0 6.757 8.129 5.142 1 1 3 7.657 7.215 0.8 0.88 0.88 0.60 0.88 0.91 He 68 7 0.871 0.871 0.889 0.912 0.890 0.864 0.915 0.874 0.724 9 0.866 0.904 0.802 6 7 0 0.897 0.859</p>