Abstract
The development of molecular biology techniques has allowed a new approach to palaeontology and studies on ancient DNA. As a plant fossil resin, amber provided a good matrix for preserving ancient biological material. Some difficulties arise when experimental work is done to extract information concerning these preserved specimens. The major risks in this type of works are the contamination with modern DNA and the degradation of the ancient DNA. A safe method to sterilize amber stones has been designed allowing the amplification of a fragment of the ancient RbcL gene from the Miocene (c.a. 25 million years). Presumably, the gene was from Hymenaea protera, an extinct member of the Leguminoseae family. The phylogenetic tree and divergence rates indicate that since although it is a well-conserved gene, and then should be a good candidate for studying the evolution of plant macrogroups, probably it is not good enough for analyzing divergence among closely related species.