While scientists have agreed for some time that a functional and objective classification system must reflect actual evolutionary processes and genetic relationships, the technological means for creating such a system did not exist until recently. In the 1990s DNA technology saw immense progress, resulting in unprecedented accumulation of DNA sequence data from various genes present in compartments of plant cells. In 1998 a ground-breaking classification of the angiosperms (the APG system) consolidated molecular phylogenetics (and especially cladistics or phylogenetic systematics) as the best available method. For the first time relatedness could be measured in real terms, namely similarity of the molecules comprising the genetic code.