Microsatellite markers reveal strong genetic structure in the endemic Chilean dolphin

• Published in: PloS one Vol. 10; no. 4; p. e0123956
• Main Authors: Pérez-Alvarez, María José, Olavarría, Carlos, Moraga, Rodrigo, Baker, C Scott, Hamner, Rebecca M, Poulin, Elie
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 21.04.2015; Public Library of Science (PLoS)
• Subjects: Animal behavior; Animals; Aquatic mammals; Bayesian analysis; Biodiversity; Biogeography; Biopsy; Cephalorhynchus; Cephalorhynchus eutropia; Cephalorhynchus hectori; Cetacea; Chile; Clustering; Coastal ecology; Coastlines; Coasts; Conservation; Delphinus delphis; Differentiation; Dispersal; Dolphins & porpoises; Dolphins (Mammals); Dolphins - genetics; Endemic species; Entanglement; Estuaries; Estuarine environments; Female; Fjords; Gene flow; Genetic diversity; Genetic markers; Genetic structure; Habitats; Male; Marine mammals; Microsatellite Repeats; Microsatellites; Mitochondrial DNA; Phylogeography; Population genetics; Population structure; Populations; Skin; Speciation; Threatened species; Tursiops truncatus; Wildlife conservation; Chile; New Zealand; South America; Oregon; South Island New Zealand; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0123956

Understanding genetic differentiation and speciation processes in marine species with high dispersal capabilities is challenging. The Chilean dolphin, Cephalorhynchus eutropia, is the only endemic cetacean of Chile and is found in two different coastal habitats: a northern habitat with exposed coastlines, bays and estuaries from Valparaíso (33°02'S) to Chiloé (42°00'S), and a southern habitat with highly fragmented inshore coastline, channels and fjords between Chiloé and Navarino Island (55°14'S). With the aim of evaluating the potential existence of conservation units for this species, we analyzed the genetic diversity and population structure of the Chilean dolphin along its entire range. We genotyped 21 dinucleotide microsatellites for 53 skin samples collected between 1998 and 2012 (swab: n = 8, biopsy: n = 38, entanglement n = 7). Bayesian clustering and spatial model analyses identified two genetically distinct populations corresponding to the northern and southern habitats. Genetic diversity levels were similar in the two populations (He: 0.42 v/s 0.45 for southern and northern populations, respectively), while effective size population was higher in the southern area (Ne: 101 v/s 39). Genetic differentiation between these two populations was high and significant (FST = 0.15 and RST = 0.19), indicating little or no current gene flow. Because of the absence of evident geographical barriers between the northern and southern populations, we propose that genetic differentiation may reflect ecological adaptation to the different habitat conditions and resource uses. Therefore, the two genetic populations of this endemic and Near Threatened species should be considered as different conservation units with independent management strategies.