A possible phylogeny based on complete mitochondrial DNA sequences from Yu et al. (2007).[39] | ||||||||||||||||||||||||||||||||||||||||||||||||
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The polar bear and the brown bear form a close grouping, while the relationships of the other species are not very well resolved.[14] |
A more recent phylogeny based on the genetic study of Kumar et al. (2017).[40] | |||||||||||||||||||||||||||||||||||||||||||||
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The study concludes that Ursine bears originated around 5 million years ago and show extensive hybridization of species in their lineage.[40] |