Development of DNA-based methods to identify CITES-protected timber species: a case study in the Meliaceae family

Violation of CITES regulations in tropical timber trade necessitates the development of accurate species identification systems. The application of available methods, mostly based on visual illustrations and descriptions of wood anatomical characteristics, proved to be difficult or even impossible, particularly on lower taxonomic levels. Further, because most of the chain-of-custody documents are externally applied marks which can easily be manipulated, control methods should be based on wood features which are inherent in the wood itself. In a case study on five closely-related genera of the Meliaceae (mahogany) family, including Swietenia sp. (listed on CITES appendix II), Khaya, Entandrophragma, and Carapa sp. (legal trade timbers), this study demonstrates the process of developing DNA markers for identification purposes. A detailed sequence analysis of several non-coding cpDNA regions resulted in an assay of seven genus-specific SNP (single nucleotide polymorphism) markers. Tools have been designed that could be applied with low-cost equipment on the basis of PCR-RFLPs without the need for sequencing or capillary electrophoresis techniques. In addition, the application of the method to wood material with degraded DNA of low overall quantity is highlighted.