the brown bear (<em>ursus arctos</em>) also known as "brown bear" has at least 16 subspecies recognized by Wilson & Reader (2005) of which at least 5 are considered extinct. These plantigrades are currently considered in danger of extinction and from the phylogenetic point of view, they have been attributed to have a polyphylogenetic origin or polyphyletic lineage, which means the sequence of arrangements of species from ancestors to the descendant through evolution.
Explanation:
Genomic analysis using different statistical methods showed that the genetic flow is not limited to pairs of closely related species. There is a high flow of ancestral genes between the Asian black bear and the ancestors of the polar bear, the brown bear and the American black bear, which explains the difficulties encountered in reconstructing the phylogeny of the bears and that, up to now, lead to the conclusion of its polyphyletic linage.
