Oliveira, Larissa Rosa de and Gehara, Marcelo C. M. and Fraga, Lúcia D. and Lopes, Fernando and Túnez, Juan Ignacio and Cassini, Marcelo H. and Majluf, Patricia and Cárdenas-Alayza, Susana and Pavés, Héctor J. and Crespo, Enrique Alberto and García, Nestor and Loizaga de Castro, Rocío and Hoelzel, A. Rus and Sepúlveda, Maritza and Olavarría, Carlos and Valiati, Victor Hugo and Quiñones, Renato and Pérez-Alvarez, Maria Jose and Ott, Paulo Henrique and Bonatto, Sandro L. (2017) 'Ancient female philopatry, asymmetric male gene flow, and synchronous population expansion support the influence of climatic oscillations on the evolution of South American sea lion (Otaria flavescens).', PLoS ONE., 12 (6). e0179442.
The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial DNA (mtDNA) and 10 nuclear microsatellites loci. We analyzed 147 sequences of mtDNA control region and genotyped 111 individuals of South American sea lion for 10 microsatellite loci, representing six populations (Peru, Northern Chile, Southern Chile, Uruguay (Brazil), Argentina and Falkland (Malvinas) Islands) and covering the entire distribution of the species. The mtDNA phylogeny shows that haplotypes from the two oceans comprise two very divergent clades as observed in previous studies, suggesting a long period (>1 million years) of low inter-oceanic female gene flow. Bayesian analysis of bi-parental genetic diversity supports significant (but less pronounced than mitochondrial) genetic structure between Pacific and Atlantic populations, although also suggested some inter-oceanic gene flow mediated by males. Higher male migration rates were found in the intra-oceanic population comparisons, supporting very high female philopatry in the species. Demographic analyses showed that populations from both oceans went through a large population expansion ~10,000 years ago, suggesting a very similar influence of historical environmental factors, such as the last glacial cycle, on both regions. Our results support the proposition that the Pacific and Atlantic populations of the South American sea lion should be considered distinct evolutionarily significant units, with at least two managements units in each ocean.
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|Publisher Web site:||https://doi.org/10.1371/journal.pone.0179442|
|Publisher statement:||© 2017 Oliveira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
|Date accepted:||29 May 2017|
|Date deposited:||13 July 2017|
|Date of first online publication:||27 June 2017|
|Date first made open access:||13 July 2017|
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