title: Chalcone synthase gene lineage diversification confirms allopolyploid evolutionary relationships of European rostrate violets.
abstract: Phylogenetic relationships among and within the subsections of the genus Viola are still far from resolved. We present the first organismal phylogeny of predominantly western European species of subsection Rostratae based on the plastid trnS-trnG intron and intergenic spacer and the nuclear low-copy gene chalcone synthase (CHS) sequences. CHS is a key enzyme in the synthesis of flavonoids, which are important for flower pigmentation. Genes encoding for CHS are members of a multigene family. In Viola, 3 different CHS copies are present. CHS gene lineages obtained confirmed earlier hypotheses about reticulate relationships between species of Viola subsection Rostratae based on karyotype data. Comparison of the CHS gene lineage tree and the plastid species phylogeny of Viola reconstructed in this study indicates that the different CHS copies present in Viola are the products of both recent and more ancient duplications.
authors.affiliation: Nationaal Herbarium Nederland, Leiden University, Leiden, The Netherlands.
authors.forename: Kevin
authors.initials: K
authors.lastname: van den Hof
authors.forename: Ronald G
authors.initials: RG
authors.lastname: van den Berg
authors.forename: Barbara
authors.initials: B
authors.lastname: Gravendeel
mesh_terms: D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D021901:DNA, Intergenic; D019143:Evolution, Molecular; D005091:Exons; D005419:Flavonoids / Q000737:chemistry; D035264:Flowers; D015971:Gene Expression Regulation, Enzymologic; D017343:Genes, Plant; D007438:Introns; D005810:Multigene Family; D010802:Phylogeny; D010858:Pigmentation; D011123:Polyploidy; D032413:Viola / Q000235:genetics*
chemical_list: D021901:DNA, Intergenic; D005419:Flavonoids; D000217:Acyltransferases; C020141:flavanone synthetase