Phylogenetic and Population Genetic Studies in Grindelia (Asteraceae: Astereae)

摘要: Grindelia is among the most taxonomically challenging groups of North American composites. The genus as a whole has an amphitropical distribution, with approximately half species native to America and Mexico remainder South America. I used DNA sequence data from nuclear ribosomal ITS ETS chloroplast psaI-accD regions revisit hypotheses on biogeographic history across genus. well-supported composed two sister clades, one other America, including Mexico. taxa are much more diverse in habit than taxa. constitute clades that largely occur different sides Continental Divide. radiation California Floristic Province (CA-FP) appears be closely related Great Basin Colorado Plateau evidently descended drought-adapted ancestors. Although Steyermark's about relationships not all supported, did recover clade corresponding his Pacific many Mexican Texan he hypothesized basal represent early diverging lineages my trees.Polyploid complexes have long been source confusion taxonomists due their combination morphological ecological variability lack obvious boundaries between putative species. (Asteraceae) CA-FP provides prime example both these attributes. Both diploid tetraploid plants within CA-FP, tetraploids predominating along coast diploids interior. phylogenetic analysis shows form clade, remain unresolved divergence. Complex variation interpreted being indicative either extensive or no taxonomic diversity. chosen follow intermediate approach, recognizing what consider ecologically distinctive ecotypes clusters In addition, emphasized appear maintain distinctiveness when growing sympatrically peripatrically field.Most diversity present tetraploids, which autotetraploids based cytogenetic prior studies. six microsatellites examine 439 individuals ten populations (nine diploid) collected near San Francisco Bay Area. wanted assess whether any genetic structure was evident both. Each genetically distinct others gene flow appeared low. grouped strongly according population taxon, it possible classify > 90% taxon using discriminant microsatellite data.