Herbarium specimens as a source of DNA for AFLP fingerprinting of Phragmites (Poaceae): Possibilities and limitations

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.