title: Historical dimensions of population structure in a continuously distributed marine species: The case of the endemic Chilean dolphin.
abstract: The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical dimension of this genetic differentiation between northern and southern populations to evaluate phylogeographic structure. Additionally, we conducted mtDNA and microsatellite analyses to detect past and recent demographic changes. The southern population was characterized by lower genetic diversity with a signal of population expansion, likely associated with ice retreat and habitat extension after the Last Glacial Maximum (LGM). In contrast, structure within the northern population was more consistent with stable historical population size. Approximate Bayesian Computation analyses suggested that during the LGM, C. eutropia persisted in the northern area; while the south was colonized by dispersal ~11,000 years ago followed by population expansion. This study shows that Chilean dolphin population structure is consistent with predictions from the Expansion-Contraction biogeographic model, with a poleward post-glacial shift revealed in current genetic structure. The results also confirm the validity of the population units previously identified, demonstrating their historical origin and highlighting the utility of integrating genetic markers with different temporal scale resolutions.
authors.affiliation: Instituto de Ecología y Biodiversidad (IEB), Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Ñuñoa, Santiago, Chile.|Centro de Investigación Eutropia, Ahumada 131 Oficina 912, Santiago, Chile.
authors.forename: M J
authors.initials: MJ
authors.lastname: Pérez-Alvarez
authors.affiliation: Centro de Investigación Eutropia, Ahumada 131 Oficina 912, Santiago, Chile.|Fundación CEQUA, 21 de Mayo 1690, Punta Arenas, Chile.|Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Raúl Bitrán1305, La Serena, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Olavarría
authors.affiliation: Centro de Investigación Eutropia, Ahumada 131 Oficina 912, Santiago, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Moraga
authors.affiliation: Marine Mammal Institute and Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR 97365, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Baker
authors.affiliation: Marine Mammal Institute and Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR 97365, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Hamner
authors.affiliation: Instituto de Ecología y Biodiversidad (IEB), Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Ñuñoa, Santiago, Chile.
authors.forename: E
authors.initials: E
authors.lastname: Poulin
mesh_terms: D000818:Animals; D002677:Chile; D004272:DNA, Mitochondrial / Q000235:genetics*; D004289:Dolphins / Q000235:genetics*; D017753:Ecosystem; D019143:Evolution, Molecular; D049810:Genetic Speciation; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats / Q000235:genetics*; D008954:Models, Biological; D010507:Periodicity; D010802:Phylogeny; D058974:Phylogeography
chemical_list: D004272:DNA, Mitochondrial