Author/Editor		Frajman, Božo; Oxelman, Bengt
Title		Reticulate phylogenetics and phytogeographical structure of Heliosperma (Sileneae, Caryophyllaceae) inferred from chloroplast and nuclear DNA sequences
Type		članek
Source		Mol Phylogenet Evol
Vol. and No.		Letnik 43
Publication year		2007
Volume		str. 140-55
Language		eng
Abstract		The Balkan Peninsula is known to be one of the most diverse and species-rich parts of Europe, but in biota has gained much less attention in phylogenetic and evolutionary studies compared to other southern European mountain systems. We used nuclear ribosomal internal transcribed spacer (ITS) sequences and intron sequences of the chloroplast gene rps16 to examine phylogenetic and biogeographical patterns within the genus Heliosperma (Sileneae, Caryophyllaceae). The ITS and rps16 intron sequences both support monophyly of Heliosperma, but the data are not conclusive with regard to its enact origin. Three strongly supported clades are found in both data sets, corresponding to Heliosperma alpestre, Heliosperma macranthum and the Heleosperma pusillum clade, including all other taxa. The interrelationships among these three differ between the nuclear and the plastid data sets. Hierarchical relationships within the H. pusillum clade are poorly resolved by the ITS data, but the rps16 intron sequences form two well-supported clades which are geogaphically, rather than taxonomically, correlated. A similar geographical structure is found in the ITS data, when analyzed with the NeighbourNet method. The apparent rate of change within Heliosperma is slightly higher for rps16 as compared to ITS. In contrast, in the Sileneae outgroup, ITS substitution rates are more than twice as high as those for rps16, a situation more in agreement with what has been found in other rate comparisons of noncoding cpDNA and ITS. Unlike most other Sileneae ITS sequences, the H. pusillum group sequences display extensive polymorphism. A possible explanation to these patterns is extensive hybridization and gene flow within Heliosperma, which together with concerted evolution may have eradicated the ancient divergence suggested by the rps16 data. (Abstract truncated at 2000 characters)
Descriptors		PLANTS ECOSYSTEM PHYLOGENY CHLOROPLASTS GENES, PLANT SEQUENCE ANALYSIS, DNA