PMC

(A) Autosomal heterozygosity frequencies and (B) and nucleotide diversity, pi, across polar and brown bear populations (Dataset S2). Acronyms of population groupings follow the description in . (C) Estimates of effective population size over time shown for one representative individual from each of the brown bear and polar bear populations: AK034 (Alaskan polar bear), APB (the ancient polar bear), ABC2 (Chichagof brown bear), ABC1 (Admiralty brown bear), RF01 (European brown bear), BB049 (Alaskan brown bear), CON001 (Yellowstone brown bear). For provenance of each individual see Dataset S1.

A) Small bear pressing down on the ribcage of a red deer; B) large bear breaking ribs by sudden jerking of head, with his teeth clamped onto the carcass; C) large bear expanding the ribcage of a red deer; D) large bear pressing down on the ribcage of a red deer.

LB =  Large bear; SB =  Small bear; Unknown bear =  UNK; LU =  Large ungulate; MU =  Medium ungulate; SU =  Small ungulate.

Median-joining network analysis of the 104 bp region of the of the mitochondrial 12S ribosomal RNA gene. The colours denote which species the samples belong to: turquoise, polar bear; red, brown bear; black, American black bear; white, Asian black bear; green, cave bear (plus one Deninger's bear); purple, sloth bear. For information on sample sizes, see main text. Circle areas are proportional to the number of individuals possessing each mitochondrial haplotype. Named haplotypes are as follows: A, hair samples 25025 and 25191, plus one modern polar bear (GU573490); B, hair samples 25027 and 25194, plus 96 brown bear from GenBank and one Asian black bear (AB302321); C, hair samples 25028, 25074, 25082, 25104, 25106 and 25202, plus three American black bear (AF303109, JX196366 and Y08520); D, five brown bear from the ABC Islands (see main text for accession numbers). The position of the Pleistocene polar bear GU573488 [] is noted by a P and is one transition away from haplotype A. The positions of the nucleotide substitutions that distinguish the haplotypes are shown, using the numbering from the polar bear NCBI reference sequence NC_003428 []. All mutational differences are transitions, apart from 1747 (underlined), which is a transversion. One unsampled intermediate node is demarked by a small point.