Ribosomal and chloroplast DNA evidence for diversification of western American Portulacaceae in the Andean region

Abstract

Sequences of the ribosomal DNA internal transcribed spacer (ITS) region and the chloroplast DNA ycf3-trnS intergenic spacer were determined for 183 samples representing Chilean and non-Chilean taxa of western American Portulacaceae and their outgroups. The data refine previous inferences of generic circumscriptions and interrelations. In particular, the data reveal that an earlier circumscription of Cistanthe Spach is polyphyletic and also reveal a North American clade comprising Claytonia L., Lewisia Pursh, Lewisiopsis R. Govaerts, and Montia L. Within the South American genera, two patterns emerge from the data: (1) in some cases, interspecific divergence is remarkably low given the markers employed and estimated number of species; and (2) where divergence of one or both markers offer phylogenetic resolution, there is conflict between them and/or with morphology. The patterns can be evaluated in terms of two phenomena: (1) morphological/ecological radiation proceeding much faster than sequence divergence; and (2) frequent hybridization. In the latter case, the gene tree patterns may distort the true timing and cladistic pattern of morphological and ecological diversification. At present, the degree to which evidence for hybridization among the Chilean Portulacaceae will prove to be the rule or the exception is unclear. Nonetheless, spatial and temporal ecological patterns in Chile generally favor hybrid formation and persistence.

Disintegrating Portulacaceae: A new familial classification of the suborder Portulacineae (Caryophyllales) based on molecular and morphological data

“…(see McNeill, 1974). However, the present circumscription was suggested by Hershkovitz (1993Hershkovitz ( , 2006 and Hershkovitz & Zimmer (2000), as their informal "Western American Portulacaceae" subgroup, on the basis of vegetative morphology as well as molecular phylogeny analysis. The reestablishment of the genus Phemeranthus exemplifies very well the previous lack of solid knowledge to resolve issues in Portulacaceae classification: molecular phylogenetic investigations provide clear evidence that the traditional concept of Talinum is polyphyletic and consists of two distinct lineages; one (i.e., Phemeranthus) takes up a cladistically basal position in Montiaceae and the other (i.e., Talinum s.str.)…”

Generic delineation, phylogeny and subtribal affinities of Phagnalon and Aliella (Compositae, Gnaphalieae) based on nuclear and chloroplast sequences

“…cpDNA ycf3-trnS, trnL intron, trnL-trnF intergenic spacer and trnT-trnL region amplification strategies. -Doublestranded DNA of the ycf3-trnS spacer was amplified by PCR and sequenced using SP43122F and SP44097R as the forward and reverse primers, respectively (Hershkovitz, 2006). Doublestranded DNA of the trnT-trnL spacer was amplified and sequenced using trnT-A2F (Cronn & al., 2002) as the forward primer and trnL-b as the reverse primer (Taberlet & al., 1991).…”

Southern isolation and northern long-distance dispersal shaped the phylogeography of the widespread, but highly disjunct, European high mountain plantArtemisia eriantha(Asteraceae)

“…Two to four individuals per population were screened for plastid DNA sequence variation, except for the populations 6-Laurichard and 8-Ladres. Three regions were amplified and sequenced using the following primers: SP43122F and SP44097R (Hershkovitz, 2006) for the intergenic spacer ycf3-trnS; 3′-trnG UUC and 5′-trnG2G (Shaw et al, 2005) for the trnG intron; rpl16F71 (Jordan, Courtney & Neigel, 1996) and Rex2 (5′-GATATTCCCTTCATTCTTCCT-3′; R. T. Kimball, University of Florida, Gainesville, FL, USA, pers. comm.)…”