Extraction, amplification and characterization of wood DNA from Dipterocarpaceae

A successful DNA extraction from wood yielding appropriate DNA quality for PCR amplification allows molecular genetic investigations of wood tissue. Genotypes, the origin of sampled material, and species can be identified based on an investigation of wood if suitable information on genetic variation patterns within and among species is available. Potential applications are in forensics and in the control of the timber and wood trade. We extracted DNA from wood of Dipterocarpaceae, a family that dominates rainforests and comprises many important timber species in Southeast Asia. Several different DNA isolation techniques were compared and optimized for wood samples from natural populations and from wood processing enterprises. The quality of the DNA was tested by spectrophotometry, PCR amplification, and PCR inhibitor tests. An average DNA yield of 2.2 mu g was obtained per 50-100 mg of dried wood sample. Chloroplast DNA (cpDNA) regions of different length were amenable to PCR amplification from the extracted DNA. Modification of DNA isolation techniques by the addition of polyvinylpyrrolidone (PVP) addition up to 3.1% into lysis buffer reduced PCR inhibition effectively. In order to evaluate the extraction method, we analyzed leaves and wood from the same tree by PCR amplification, genotyping and sequencing of chloroplast microsatellites.