Análisis preliminar de la variabilidad genética y de los límites específicos de Escallonia alpina y E. rubra (Escalloniaceae)

SANTIAGO MORELLO; LILIANA M. GIUSSANI; SILVANA M. SEDE

DARWINIANA

INSTITUTO DE BOTÁNICA DARWINION

Lugar: Buenos Aires; Año: 2013 vol. 1 p. 227 - 236

0011-6793

Escallonia alpina and E. rubra (Escalloniaceae) are distributed in the same geographical region in the southern Andes; they are differentiated by few diagnostic morphological characters such as flower arrangement, and type and presence of glands. A morphological gap between both species is absent in some populations; in addition, intermediate forms have been recognized and described as hybrids. The aim of this work is to examine the genetic variation in populations of Escallonia alpina and E. rubra, and to analyze if there is a correspondence between genetic and morphological variability. We studied the morphology of 39 individuals belonging to five populations, which were also used to perform an AFLP analysis. We conducted ordination, clustering and Bayesian assignment analyses to investigate the relationship among individuals, and we calculated genetic diversity indices and a Mantel test. As a result of the morphological analysis, two populations were assigned to each species, while the remaining population could not be assigned unequivocally to any of  the two species, as the individuals exhibited an intermediate morphology. A strong correspondence between traditional morphological characters and the AFLP pattern was observed. Our preliminary morphological and molecular evidence support Escallonia alpina and E. rubra as two distinct species. The variability found in the intermediate population might be the result of inter-specific hybridization or incomplete lineage sorting.