AFLP fingerprinting reveals pattern differences between template DNA extracted from different plant organs.

AFLP (amplified fragment length polymorphism) fingerprinting of cultivars of bread wheat (Triticum aestivum) and some of its wild relatives has allowed the efficient detection of large numbers of polymorphic amplified fragments. While the reproducibility of fingerprints in repeated experiments is high, pattern differences were observed between fingerprints obtained from seed and leaf DNA template from the same wheat accession. These distinct organ specific amplified DNA fragments were shown to be due neither to genotypic mixtures nor to pathogen contamination. They are likely a result of differences in DNA methylation between organs. Even greater numbers of organ specific amplified fragments were observed when fingerprints obtained from the root and shoot of individual seedlings of the wheat relatives Aegilops mutica and Aegilops speltoides were compared. This phenomenon underlines the importance of ensuring that DNA is extracted from physiologically uniform tissue in phylogenetic studies based on AFLP fingerprints. For this purpose, mature seed is a convenient source.