Genetic diversity of endangered brown bear (Ursus arctos) populations at the crossroads of Europe, Asia and Africa

Abstract

International audienceAim Middle East brown bears (Ursus arctos syriacus Hemprich and Ehrenberg, 1828) are presently on the edge of extinction. However, little is known of their genetic diversity. This study investigates that question as well as that of Middle East brown bear relationships to surrounding populations of the species. Location Middle East region of south-western Asia. Methods We performed DNA analyses on 27 brown bear individuals. Twenty ancient bone samples (Late Pleistocene to 20th century) from natural populations and seven present-day samples obtained from captive individuals were analysed. Results Phylogenetic analyses of the mitochondrial sequences obtained from seven ancient specimens identify three distinct maternal clades, all unrelated to one recently described from North Africa. Brown bears from Iran exhibit striking diversity (three individuals, three haplotypes) and form a unique clade that cannot be linked to any extant one. Individuals from Syria belong to the Holarctic clade now observed in Eastern Europe, Turkey, Japan and North America. Specimens from Lebanon surprisingly appear as tightly linked to the clade of brown bears now in Western Europe. Moreover, we show that U. a. syriacus in captivity still harbour haplotypes closely linked to those found in ancient individuals. Main conclusion This study brings important new information on the genetic diversity of brown bear populations at the crossroads of Europe, Asia and Africa. It reveals a high level of diversity in Middle East brown bears and extends the historical distribution of the Western European clade to the East. Our analyses also suggest the value of a specific breeding programme for captive populations

A range-wide synthesis and timeline for phylogeographic events in the red fox (Vulpes vulpes)

“…It appears that especially some southern wolf populations did not expand after the Pleistocene glaciations: two distinct lineages survived south of the Himalayas [9]. In brown bears, a similar situation has been described for Syria and Iran [11,13], and in red foxes analogous evidence exists for Iberia [26,48] and Serbia (Figure  3; data from Kirschning et al [22]).…”

“…Besides their ecology, they share remarkably similar phylogeographic patterns with the red fox. All three species are characterized by very widespread Holarctic mitochondrial lineages that are distributed across Eurasia and North America, and only some locally restricted lineages - indicating dispersal limitations in some regions of the Holarctic [8,9,11-13,34,55]. …”

The role of Pleistocene glaciations in shaping the evolution of polar and brown bears. Evidence from a critical review of mitochondrial and nuclear genome analyses

“…Secondly, the mitochondrial estimates for the MRCA of brown and polar bears may have been underestimated because several geographically isolated populations of U. arctos were not included in molecular dating analyses. Indeed, divergent mtDNA haplotypes have been detected in short D-loop or cytochrome b sequences of brown bears currently found in Iran, Pakistan, and Mongolia (Gobi Desert), as well as in extinct populations of North Africa [32][33][34][35].…”

Complex patterns of population genetic structure of moose, Alces alces, after recent spatial expansion in Poland revealed by sex-linked markers

“…In recent years, human activity directly and indirectly influenced the demography of free-living animals and, as a result, may have profound consequences for their spatial genetic structure (Nussey et al 2006; Haanes et al 2010; Hundertmark and Van Daele 2010). Forest fragmentation and direct persecution by humans have resulted in dramatic reductions of boreal species’ ranges, and in many cases, present-day populations survived as small isolated groups only (Calvignac et al 2009). Isolated populations, due to small size and strong genetic drift, exhibit reduced levels of genetic variation and may possess unique mtDNA haplotypes (Rowe et al 2004).…”