Gene Flow and Maintenance of Genetic Diversity in Invasive Mosquitofish

A new work from researches of the LIG and the IEA has been published in PLoS ONE. In this paper, the authors give insights in how gene flow between invasive populations shapes genetic diversity of Gambusia holbrooki in Mediterranean streams. Abstract:

Genetic analyses contribute to studies of biological invasions by mapping the origin and dispersal patterns of invasive species occupying new territories. Using microsatellite loci, we assessed the genetic diversity and spatial population structure of mosquitofish (Gambusia holbrooki) that had invaded Spanish watersheds, along with the American locations close to the suspected potential source populations. Mosquitofish populations from the Spanish streams that were studied had similar levels of genetic diversity to the American samples; therefore, these populations did not appear to have undergone substantial losses of genetic diversity during the invasion process. Population structure analyses indicated that the Spanish populations fell into four main clusters, which were primarily associated with hydrography. Dispersal patterns indicated that local populations were highly connected upstream and downstream through active dispersal, with an average of 21.5% fish from other locations in each population. After initially introducing fish to one location in a given basin, such dispersal potential might contribute to the spread and colonization of suitable habitats throughout the entire river basin. The two-dimension isolation-by-distance pattern here obtained, indicated that the human-mediated translocation of mosquitofish among the three study basins is a regular occurrence. Overall, both phenomena, high natural dispersal and human translocation, favor gene flow among river basins and the retention of high genetic diversity, which might help retain the invasive potential of mosquitofish populations.

More information can be found here.

Adult female of G. holbrooki

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Díez-del-Molino D, Carmona-Catot G, Araguas R-M, Vidal O, Sanz N, et al. (2013) Gene Flow and Maintenance of Genetic Diversity in Invasive Mosquitofish (Gambusia holbrooki). PLoS ONE 8(12): e82501. doi:10.1371/journal.pone.0082501

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Colonization routes of the invasive mosquitofish introduced to Europe

A new work from researches of the LIG has been released today in the Biological Invasions journal. In this paper, the authors try to clarify the main routes of colonization of the European continent by the highly invasive species of freshwater fish Gambusia holbrooki. Abstract:

Biological invasions are considered one of the main anthropogenic factors that reduce the abundance of native species. Understanding the patterns of population structure and behavior of introduced species is important to determine invasion sources and pathways. We set out to advance our knowledge about the invasive mosquitofish Gambusia spp. by screening variation at six microsatellite loci. We also evaluated six American samples (four of G. holbrooki and two of G. affinis) to identify the most likely source of the populations that established in Europe. The results showed that most introduced populations harbored a considerable amount of gene diversity, probably because of multiple introductions and secondary contacts. Populations displayed strong genetic differentiation that was mainly associated with geographical distance. At least two main routes of colonization of G. holbrooki seem to have occurred in Europe. The first, was consistent with the historical records of the species invading the Iberian Peninsula. A second, and more recent colonization, probably occurred in Greece and, from there, France.

Further information about the paper can be accessed here.

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Sanz, N., Araguas, R.M. , Vidal, O., Diez-del-Molino, D., Fernández-Cebrián, R., García-Marín, J.L. (2013) Genetic characterization of the invasive mosquitofish (Gambusia spp.) introduced to Europe: population structure and colonization routes. Biological Invasions. October 2013, Volume 15, Issue 10, pp 2333-2346

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