Holarctic Phylogeography of Arctic Charr (Salvelinus Alpinus L.) Inferred From Mitochondrial Dna Sequences

Abstract

This study evaluated mitochondrial DNA (mtDNA) sequence variation in a 552-bp fragment of the control region of Arctic charr (Salvelinus alpinus) by analyzing 159 individuals from 83 populations throughout the entire range of the complex. A total of 89 (16.1%) nucleotide positions were polymorphic, and these defined 63 haplotypes. Phylogenetic analyses supported the monophyly of the complex and assigned the observed haplotypes to five geographic regions that may be associated with different glacial refugia. Most notably, a formerly defined major evolutionary lineage (S. a. erythrinus) ranging from North America across the Arctic archipelago to the Eurasian continent has now been partitioned into the Arctic group and the newly identified Siberian group. The Beringian group, formed entirely by specimens assigned to S. malma (Dolly Varden), encompassed the area formerly assigned to S. a. taranetzi. The latter, due to a unique haplotype, became the basal member of the Arctic group. Overall, the S. alpinus complex reflects divergent evolutionary groups coupled with shallow intergroup differentiation, also indicated by an analysis of molecular variance that attributed 73.7% (P < 0.001) of the total genetic variance among groups. Time estimates, based on sequence divergence, suggest a separation of the major phylogeographic groups during early to mid-Pleistocene. In contrast, colonization of most of today's range started relatively recently, most likely late Pleistocene during the last retreat of ice sheets some 10,000-20,000 years ago. This time scale obviously is too shallow for detecting significant variation on a smaller scale using mtDNA markers. However, other studies using nuclear microsatellite DNA variation strongly suggested ongoing evolution within groups by revealing strong population-genetic substructuring and restricted gene flow among populations. Thus, Arctic charr could serve as a model organism to investigate the linkage between historical and contemporary components of phylogeographic structuring in fish, and, with a global perspective of the distribution of genetic variation as a framework, meaningful comparisons of charr studies at a smaller geographic scale will now be possible.

Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada’s Great Bear Lake

“…MtDNA data collection methods are described in Harris et al (2013). Briefly, the left domain of the control region (d-loop) was amplified with primers tPro2 (Brunner et al, 2001) and ARCH1 (Alekseyev et al, 2009). The target amplification product was then sequenced with primer tPro2 using the Applied Biosystems Big Dye Terminator v3.1 Terminator Cycle Sequencing kit (Applied Biosystems).…”

Hibernation in an Antarctic Fish: On Ice for Winter

“…There is clear evidence of extremely rapid adaptations of fish to new habitats and environments, with ecological specialization and morphological differentiation, generally in accordance with genetic divergence [15,[42][43][44]. Considerable attention has been given to the evolution of developmental mechanisms and adaptation to cave environments [36,38,39], but less attention has been given to other habitat associated morphological plasticity.…”

Nucleotide variation in the mitochondrial genome provides evidence for dual routes of postglacial recolonization and genetic recombination in the northeastern brook trout (Salvelinus fontinalis)

“…We used an evolutionary rate of 3.018%/million years calculated from the sequence divergence between brook trout from this study and Arctic charr reference sequence AF154851 (overall mean distance = 0.06036) and the time of divergence (~1 million years) between brook trout and Arctic charr reported by Brunner et al (2001).…”