Mitogenetic structure of brown bears (Ursus arctos L.) in northeastern Europe and a new time frame for the formation of European brown bear lineages

Abstract

We estimated the phylogenetic relationships of brown bear maternal haplotypes from countries of northeastern Europe (Estonia, Finland and European Russia), using sequences of mitochondrial DNA (mtDNA) control region of 231 bears. Twenty-five mtDNA haplotypes were identified. The brown bear population in northeastern Europe can be divided into three haplogroups: one with bears from all three countries, one with bears from Finland and Russia, and the third composed almost exclusively of bears from European Russia. Four haplotypes from Finland and European Russia matched exactly with haplotypes from Slovakia, suggesting the significance of the current territory of Slovakia in ancient demographic processes of brown bears. Based on the results of this study and those from the recent literature, we hypothesize that the West Carpathian Mountains have served either as one of the northernmost refuge areas or as an important movement corridor for brown bears of the Eastern lineage towards northern Europe during or after the last ice age. Bayesian analyses were performed to investigate the temporal framework of brown bear lineages in Europe. The molecular clock was calibrated using Beringian brown bear sequences derived from radiocarbon-dated ancient samples, and the estimated mutation rate was 29.8% (13.3%-47.6%) per million years. The whole European population and Western and Eastern lineages formed about 175,000, 70,000 and 25,000 years before present, respectively. Our approach to estimating the time frame of brown bear evolution demonstrates the importance of using an appropriate mutation rate, and this has implications for other studies of Pleistocene populations.

Surprising migration and population size dynamics in ancient Iberian brown bears ( Ursus arctos )

“…Under traditional glacial refugia hypotheses (4,17), the extant brown bear phylogeographic structure derives from ancestral glacial refugia: the western lineage originating from Iberia, Italy, and the Balkans, and the eastern lineage possibly derived from a Carpathian refugium (14,16). In contrast to such a strict refugial model, but in concordance with a continuous European prehistoric population, we have identified a sequence from a Pleistocene Iberian brown bear from Arlanpe site (the Basque country) that belongs to the eastern clade.…”

“…In addition, the different estimates for the Spanish population are in the range of what is observed for the European population taken as a whole (Table 1 and SI Table 2). Therefore, the effective size is expected to be large and probably well Ͼ26,000 individuals [the minimum of the 95% confidence range, estimated in Saarma et al (16)]. …”

“…The two western subgroups are believed to have originated from two ancestral glacial refugia (4). The eastern lineage is proposed to have expanded from glacial refugia placed in the Carpathian Mountains (14,16).…”

“…The effective size then was calculated assuming a neutral model of molecular evolution ( ϭ 2Ne , where is the mutation rate for the complete sequence per generation for S and , but the mutation rate per site per generation for MLE and MPE). We assumed two possible mutation rates (10% and 29.8% substitution per site per million years) according to the literature (4,16).…”

Influence of Holocene environmental change and anthropogenic impact on the diversity and distribution of roe deer

“…For example, the substitution rate from our study (3.69 Â 10 À7 s.s.yr À1 ) is similar to that for the ancient brown bear (Saarma et al, 2007) and bison (Shapiro et al, 2004) (3.2 Â 10 À7 and 3.0 Â 10 À7 s.s.yr À1 , respectively). In fact, reviews show broad consistency among a wide range of studies (Ho et al, 2005(Ho et al, , 2008.…”