Resumo

COULLERI, Juan Pablo. Gene flow and local adaptation: Antagonistic forces shape populations of Ilex dumosa (Aquifoliaceae). Bol. Soc. Argent. Bot. [online]. 2010, vol.45, n.3-4, pp.333-342. ISSN 1851-2372.

The evolutionary forces acting in a set of populations may vary in space, resulting in Genotype x Environment interaction for Darwinian fitness, fixing in some populations adaptative traits of a local population to a specific environmental conditions or, by gene flow homogenize the genes frequencies and make a set of population adapted to a group of environments. This paper tries to elucidate the population dynamics of a set of populations of Ilex dumosa Reiss., in which was measured quantitative traits of six populations from six geographic regions and test their responses to environmental changes. The experimental approach was made in common garden experiment and by reciprocal transplant experiment. Local adaptation was investigated both by native superiority over non-natives, and by comparing the observed performance of a population to the fitted value of a reduced statistical model that showed the populations' performance at all sites and the performance of all other populations at its home site. Were found evidence of a core population in the center of the distribution area, homogenized by gene flow, and one marginal population with patterns of local adaptation, evidenced the with highest native superiority in his environment, and the worst behavior in the other environments.

Palavras-chave : Darwinian fitness; Genotype x environment interaction; Marginal speciation; Reciprocal transplant experiment; Stabilizing selection.

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