Nuclear Genomic Sequences Reveal that Polar Bears Are an Old and Distinct Bear Lineage

@article{Hailer2012NuclearGS,
  title={Nuclear Genomic Sequences Reveal that Polar Bears Are an Old and Distinct Bear Lineage},
  author={Frank Hailer and Verena Esther Kutschera and Bj{\"o}rn Mikael Hallstr{\"o}m and Denise Klassert and Steven R. Fain and Jennifer A. Leonard and {\'U}lfur {\'A}rnason and Axel Janke},
  journal={Science},
  year={2012},
  volume={336},
  pages={344 - 347}
}
Ancient Bears Polar bears are well known for adapting to their cold Arctic climate. Some recent studies, based on mitochondrial DNA, concluded that they are a relatively young species and that these adaptations occurred quite quickly. Although mitochondrial DNA is regularly used to estimate evolutionary history, it has some well-known drawbacks, including sex-biased dispersal and hybridization. Thus, Hailer et al. (p. 344) looked at neutral genetic data that are distributed more widely across… 
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