Phylogenetic and phylogeographic analysis of the western Mediterranean Arenaria section Plinthine (Caryophyllaceae) based on nuclear, plastid, and morphological markers

Abstract

Arenaria sect. Plinthine is an easily distinguishable morphologically cohesive group encompassing 14 species and five additional subspecies. To explore phylogenetic relationships and search for phylogeographic patterns in a group that is restricted to the western Mediterranean, independent and combined analyses of four datasets (morphological characters and sequences from nuclear and plastid DNA: nrITS, trnT–trnL, trnL–trnF) were conducted using Maximum Parsimony, Neighbour–Joining, Maximum Likelihood and Bayesian Inference. Monophyly of the section is supported by the data, the ITS sequences show full agreement with taxonomy for one third of the taxa, and the high number of trnL–F haplotypes found in SE Spain (7 of 11) is consistent with the fact that this region is one of the hotspots of biodiversity in the Mediterranean. However, a number of less easily interpretable results have been obtained, despite considerable ITS variation (43 parsimony informative characters within the ingroup) and a reasonable intraspecific sampling for this marker. These results are: low resolution at deep nodes of the ingroup, partial discordance between taxonomy and ITS sequences particularly for widespread taxa, and lack of congruence not only between the topologies of the plastid and nuclear trees but also between the two plastid trees. It is proposed that a combination of factors (rampant aneuploidy, polyploidy, hybridization, lineage sorting, and concerted evolution of ITS sequences) are responsible for the incongruent but not totally unexpected results.

Molecular phylogenetic analysis ofArenaria(Caryophyllaceae: tribe Arenarieae) and its allies inferred from nuclear DNA internal transcribed spacer and plastid DNA rps16sequences

“…, box E). In our study, the monophyly of section Plinthine is supported in the ITS and plastid DNA phylogenetic trees, confirming the results of previous molecular phylogenetic studies (Valcárcel et al ., ; Greenberg & Donoghue, ). There are also several morphological synapomorphies supporting the monophyly of section Plinthine (Valcárcel et al ., ).…”

“…In our study, the monophyly of section Plinthine is supported in the ITS and plastid DNA phylogenetic trees, confirming the results of previous molecular phylogenetic studies (Valcárcel et al ., ; Greenberg & Donoghue, ). There are also several morphological synapomorphies supporting the monophyly of section Plinthine (Valcárcel et al ., ). This natural group is geographically restricted to the western Mediterranean and the morphology of these species is distinctive compared with the rest of Arenaria (Valcárcel et al ., ; Fig.…”

Narrow endemics of the Almeria Province (Andalusia, Spain) differ in their traits and ecological niche compared to their more widespread congeners

“…For five genera, published phylogenies were used to select the most closely related widespread species (Arenaria: Valcàrcel et al 2006;Centaurea: Víctor et al 2007; Genista: Pardo et al 2004;Festuca: Torrecilla and Catalàn 2002;Carex: Escudero et al 2008). For the other genera, no phylogeny is available, or the published phylogenies do not include our endemic species.…”

Monophyly, phylogenetic position and the role of hybridization in Schoenoxiphium Nees (Cariceae, Cyperaceae)

“…Reticulate evolution is well documented among plants throughout their genealogical histories (Rieseberg, 1997;Mallet, 2005). Phylogenetic incongruence between different plant genomes has frequently been found in numerous molecular studies (Pirie et al, 2008;Valcárcel et al, 2006;Vargas et al, 2009). However, other factors can also cause discrepancies between gene trees, including incomplete lineage sorting, nonhomologous sampling of duplicated genes, and horizontal gene transfer (Álvarez and Wendel, 2003;Maddison, 1997;Sang and Zhong, 2000).…”