Data from: "Polar bear (Ursus maritimus) transcriptome assembly and SNP discovery" in Genomic Resources Notes accepted 1 August 2013-30 September 2013

Polar bears (Ursus maritimus) in the Western Hudson Bay subpopulation have been declining in size and body condition for decades, as climate change causes earlier sea ice breakup, reduced hunting time on the ice, and an increasingly long fasting season. As Western Hudson Bay females have decreased in size, rates of litter production and average litter size have also decreased, while cub mortality and average time to independence have increased. Although these changes have potential evolutionary consequences, little is yet known about the adaptive genetic variation in body size or fat accumulation that would have to underlie any such change. In this study, we used high-throughput Illumina sequencing to develop SNPs from pooled blood and fat transcriptomes, using samples from five adult female polar bears and five (unrelated) dependent cubs. In total, we generated 371,258 transcripts of which 36,755 were deemed to be "full length" (i.e., covered more than 90% of their best BLAST hit), and we identified 63,020 SNPs. Since this study was conducted, we have used a subset of these SNPs to develop an Illumina BeadArray for quantitative genetics research in Western Hudson Bay.

西哈德逊湾（Western Hudson Bay）亚种群的北极熊（Ursus maritimus）数十年来体型与身体状况持续衰退，因气候变化引发海冰提前消融，导致其在海冰上的狩猎时长缩短，禁食期愈发漫长。随着西哈德逊湾雌性北极熊体型减小，其产仔率与平均窝产仔数均有所下降，而幼崽死亡率及幼崽平均独立时长则呈上升趋势。尽管此类变化存在潜在的进化效应，但目前学界对介导上述变化的、与体型或脂肪积累相关的适应性遗传变异（adaptive genetic variation）仍知之甚少。本研究采用高通量Illumina测序技术，以5只成年雌性北极熊与5只无亲缘关系的依赖幼崽的血液与脂肪混合转录组为材料开发单核苷酸多态性（Single Nucleotide Polymorphisms, SNPs）标记。最终共获得371258条转录本，其中36755条被鉴定为"全长转录本"（即覆盖其最优BLAST比对命中序列90%以上的区域），并筛选得到63020个SNPs。本研究完成后，我们利用其中部分SNPs开发了一款Illumina微珠芯片（Illumina BeadArray），用于西哈德逊湾北极熊的数量遗传学研究。