Patrones de diversidad y estructura genética en especies antárticas y subantárticas de Nacella (Nacellidae)
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Magallanes
Abstract
La biogeografía del Océano Austral es el resultado
de la compleja interacción de distintas fuerzas
macroevolutivas sobre su particular biota en el
tiempo y en el espacio. Los procesos de tectónica
de placas que derivaron en la separación de los
continentes junto al establecimiento de la Corriente
Circumpolar Antártica y el enfriamiento paulatino
de la región desde el Eoceno se han asociado
directamente a la composición, abundancia
y distribución de su fauna marina bentónica.
Más recientemente, los procesos glaciales
del Cuaternario impactaron fuertemente la
distribución de la variación genética intraespecífica
en una variedad de taxones. El género Nacella
(Patellogastropoda: Nacellidae) incluye 11
especies nominales que se distribuyen en distintas
provincias del Océano Austral. En este estudio se
compararon los patrones de diversidad y estructura
genética a nivel del DNA mitocondrial de cuatro
especies de Nacella provenientes de Antártica
marítima (Nacella concinna), Sudamérica (Nacella magellanica) y de dos islas ubicadas en el sector
Índico del Océano Austral: Kerguelén (Nacella
edgari) y Marión (Nacella delesserti). Bajos niveles
de diversidad genética y ausencia de estructura
caracterizan a cada una de las especies analizadas
lo que muestra el tremendo impacto del avance
y retroceso de los hielos sobre la demografía de
todas ellas. Baja diversidad haplotípica, genealogías
cortas y las demografías específicas sugieren la
ocurrencia de efectos poblacionales más severos
en Antártica marítima e Isla Marión que en el resto
de las regiones subantárticas.
The biogeography of the Southern Ocean is the result of the complex interaction of different macroevolutionary forces over its particular biota in space and time. Plate tectonics processes derived in the separation of the continents, together with the establishment of the Antarctic Circumpolar Current and the gradual cooling of the region since the Eocene, are directly associated to the composition, abundance, and distribution of its marine benthic fauna. More recently, glacial processes of the Quaternary strongly impacted the distribution of the intraspecific genetic variation in different taxa. The genus Nacella (Patellogastropoda: Nacellidae) includes 11 nominal species that are distributed in different provinces of the Southern Ocean. In this study, we compared mitochondrial DNA patterns of genetic diversity and structure in four Nacella species from maritime Antarctica (Nacella concinna), South America (Nacella magellanica), and two islands located in the Indian sector of the Southern Ocean: Kerguelen (Nacella edgari), and Marion (Nacella delesserti). Low levels of genetic diversity and absence of genetic structure characterize each one of the analyzed species showing the major impact of ice advances and retreats over the species’ demographies. Low haplotypic diversity, short genealogies and specific demographies suggest the occurrence of more severe population effects in maritime Antarctica and Marion Island than in the rest of the subantarctic provinces.
The biogeography of the Southern Ocean is the result of the complex interaction of different macroevolutionary forces over its particular biota in space and time. Plate tectonics processes derived in the separation of the continents, together with the establishment of the Antarctic Circumpolar Current and the gradual cooling of the region since the Eocene, are directly associated to the composition, abundance, and distribution of its marine benthic fauna. More recently, glacial processes of the Quaternary strongly impacted the distribution of the intraspecific genetic variation in different taxa. The genus Nacella (Patellogastropoda: Nacellidae) includes 11 nominal species that are distributed in different provinces of the Southern Ocean. In this study, we compared mitochondrial DNA patterns of genetic diversity and structure in four Nacella species from maritime Antarctica (Nacella concinna), South America (Nacella magellanica), and two islands located in the Indian sector of the Southern Ocean: Kerguelen (Nacella edgari), and Marion (Nacella delesserti). Low levels of genetic diversity and absence of genetic structure characterize each one of the analyzed species showing the major impact of ice advances and retreats over the species’ demographies. Low haplotypic diversity, short genealogies and specific demographies suggest the occurrence of more severe population effects in maritime Antarctica and Marion Island than in the rest of the subantarctic provinces.
Description
Keywords
Ciencia, Biogeografía, Filogeografía, Corriente circumpolar antártica, Nacella, Southern ocean, Biogeography, Phylogeography, Antarctic Circumpolar Current, Isla Marión
Citation
Anales Instituto Patagonia (Chile), 2016. Vol. 44(3):49-64