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Gayana (Concepción)

versión On-line ISSN 0717-6538

Resumen

VICTORIANO, Pedro F et al. Idiosyncratic patterns of genetic diversity of native fishes from Río San Pedro (Valdivia River Basin, Región de los Ríos, Chile): a system from glaciated region in southern Chile. Gayana (Concepc.) [online]. 2012, vol.76, suppl.1, pp. 01-09. ISSN 0717-6538.  http://dx.doi.org/10.4067/S0717-65382012000100007.

We studied the levels and patterns of genetic variability in eight species of native fishes from the Valdivia River Basin (Región de los Rios, Chile), with the aim to estimate microevolutionary differences in species with similar ecological and historical conditions. The species considered were Diplomystes camposensis, Percilia gillissi, Galaxias platei, G. maculatus, Basilichthys australis, Percichthys trucha, Aplochiton zebra and A. taeniatus. We compared genetic diversity indexes both intra and inter-zones, and genetic structure, based on sequences of the control region for different sections along the river. In addition, we recovered relationships among haplotypes and their spatial distribution for each species, based on statistical parsimony networks. Estimators of past demographic behavior (D Tajima, Fs-Fu and mismatch analysis were also obtained. The results suggest that both patterns of genetic diversity in the river such as demographic responses are species specific. The most variable and strongest structured species in the river were G. maculatus and A. taniatus. P. trucha showed high structure values but its genetic variation was lower than the first two species. The less variable and less subdivided species were D. camposensis and P. gillissi. The remaining species showed levels of variability and structure intermediate between the two extreme patterns mentioned above. The differences among species are attributed to idiosyncratic biological attributes such as level of specificity in the use of aquatic habitat, population abundances, and historical migration patterns. In the case of G. maculatus, high levels of variability are attributed to the historical maintenance of high and stable effective population sizes, due to the ability to use both marine and freshwater habitats. Low levels of genetic diversity and indicators of historical reduction in effective population size, suggests that D. camposensis and P.gillissi were more sensitive and more exposed to population reduction. Results are discussed regarding ecological, biological, and historical factors.

Palabras clave : native fishes,; genetic variation,; genetic conservation,; Chile,; glaciations..

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