Phylogeography, genetic diversity and population structure in Oxalis sect. Palmatifoliae, a Patagonian endemic group

LOPEZ, ALICIA; BONASORA, MARISA

Congreso; Botany Conference 2017; 2017

Oxalis section Palmatifoliae is a monophylleticclade, endemic to southern Argentina that includesfive species: O. adenophylla, O. enneaphylla, O.laciniata, O. loricata and O. morronei. Thedistribution of this section includes the highAndean mountains, up to 2200 meters, growing evenon the sea coast, in both Patagonian ecoregions:High Andes and Steppe according to Cabrera. Thegoals were (1) to analyze the genetic diversityand its distribution within and among populations(2) to model its extant distributions to contrastwith the phylogeographical patterns recovered foreach species; and (3) to analyze the behavior ofthe section as a unit regarding the sameparameters considered for the species level. Weanalyze 236 individuals of 27 natural populationsfor the five species. The resulting data matrixwas analyzed using GenAlEx. Genetic diversitywithin and among populations were measured by thepercentage of polymorphic bands, the effective andobserved number of alleles, Shannon?sinformation index, and frequency-down-weightedmarker. A hierarchical cluster analysis of geneticdistance values was performed using the UPGMA, anda Discriminant Analysis was also carried out. Inaddition, an AMOVA procedure was performed. Allthe statistical analyses were carried out usingInfoStat. PCoA was used to explore relationshipsamong population in FADM. Based on ISSR (intersimple sequence repeat) markers and distributionmodelling as implemented in Maxent, we performedtwo different analyzes. The first analysisincluded all the populations of each of the fivespecies; and the other one grouping all theindividuals of the section but not taking inconsideration the separation in species. Oursresults allows us to hypothesize that there is apattern of differentiation within and amongpopulations of the five species considered at thegenetic level that can be test assessing thegenetic structure and diversity. Distributionmodelling is in agreement with the presentdistribution of all the species of the section butalso suggests the possibility of occurrence in theHigh Andes regions where no one of this specieswere ever found. Then, we proposed that ChubutRiver acts as a natural barrier to speciesdispersion and colonization. Furtherinvestigations are necessary to test whethergenetic structure and genetic variation within andamong populations resulted from random populationgenetic processes or are the result of historicalprocesses.