Search

Herbarium collections are a valuable source of genetic information. Even though the DNA obtained from the specimens is often highly fragmented and present in small quantities, it has been successfully used particularly for DNA sequencing and microsatellite analysis. The present study shows that the quality is often sufficient for use also for AFLPs. With this technique, a considerable number of DNA fragments with unknown sequence from the entire genome of the plant are amplified, often with the purpose of phylogeographic studies or analyses of interrelationships of closely related species. In order to avoid the effects of potential artefacts resulting from DNA degradation, such as "false polymorphisms", it is suggested that fresh samples should always be included for comparison, and that AFLP chromatograms based on herbarium specimens should be included in analyses only when they contain AFLP fragments monomorphic among the fresh samples, and when signal quality is comparable to that of fresh samples. © 2008 Springer-Verlag.

Within the genus Phragmites (Poaceae), the species P. australis (the common reed) is virtually cosmopolitan, and shows considerable variation in ploidy level and morphology. Genetic variation in Phragmites was studied using AFLPs, and analysed with parsimony and distance methods. Groups of P. australis strongly supported in the analyses include one that comprises all South American clones, a distinct group from the US Gulf Coast, and a group of E. Asian and Australian octoploids. Among the other species, the paleotropical P. vallatoria is supported as monophyletic and most closely related to the paraphyletic P. mauritianus and to the Gulf Coast and S. American groups. The E. Asian species P. japonicus is closely related to a group of P. australis clones mostly from central North America. Tetraploidy predominates in the genus, and optimisation of chromosome numbers onto the phylogeny shows that higher ploidy levels have evolved many times. © Springer-Verlag 2006.