INVESTIGADORES
MARCHELLI Paula
artículos
Título:
The Effects of Quaternary Glaciations in Patagonia As Evidenced By Chloroplast DNA Phylogeography Of Southern Beech Nothofagus obliqua.
Autor/es:
AZPILICUETA, M.M.; MARCHELLI, P; GALLO, L A
Revista:
TREE GENETICS & GENOMES
Editorial:
SPRINGER HEIDELBERG
Referencias:
Año: 2009 vol. 5 p. 561 - 571
ISSN:
1614-2942
Resumen:
Climatic oscillations during the Quaternarystrongly affected the distribution of warm-temperate treespecies, which experienced local restrictions into ice-freeareas and posterior expansions. To evaluate the impact ofthese range movements on the genetic structure ofpopulations, we performed a phylogeographical analysisof the species Nothofagus obliqua with chloroplast DNAmarkers. A total of 27 populations covering the wholenatural distribution range were analyzed using polymerasechain reaction-restriction fragment length polymorphism.Diversity (hT, hS), allelic richness (rg), and differentiationamong populations for unordered (GST) and ordered alleles(NST) were calculated. The relationships among haplotypeswere evaluated by the construction of a minimum spanningnetwork. The spatial distribution of the genetic variationwas analyzed through a Mantel test and with a nestedanalysis of molecular variance to differentiate betweengeographic regions. The screening of 11 non-codingregions allowed the identification of 14 haplotypes. A highgenetic differentiation was detected (NST=0.875 and GST=0.824) with the existence of phylogeographic structure (p<0.05). The distribution of the genetic variation was partiallyexplained by the topography of the region when thepopulations were divided longitudinally into CoastalMountains, Central Valley, and Andes Mountains (RT=0.093, p=0.001). In agreement with pollen records, ourresults support the hypothesis of Coastal refuges since theregion harbors high diversity together with older andprivate haplotypes. Long-lasting persistence of someCoastal populations without contribution to recolonizationis proposed. Additional refuges are alsopostulated along the Andes and Longitudinal Valley.Survival in multiple glacial refuges is discussed togetherwith the possible migratory routes.
