Development of a diagnostic DNA marker for the geographic origin of Shorea leprosula

Abstract

The development of sequence characterized amplified region (SCAR) markers derived from amplified fragment length polymorphisms (AFLPs) is described for Shorea leprosula. An AFLP fragment that showed nearly complete differentiation between Borneo and Sumatra was gel-extracted, sequenced, and converted into a SCAR marker using the inverse polymerase chain reaction (PCR) technique. The single nucleotide polymorphism (SNP) that originally caused the AFLP was found in the MseI restriction site. Differentiation between islands was detected either as size variation of the codominant SCAR marker or after digestion of the PCR products with the restriction enzyme MseI (PCR-RFLP). Size variation was due to insertions/deletions found within the sequenced region that flanked the original AFLP fragment. After genotyping 151 samples of S. leprosula from 14 populations in Sumatra and Borneo, all but one sample from Sumatra were homozygous for one size variant (427 bp), while S. leprosula populations from Borneo showed different genotypes than Sumatra populations and variation not only among populations but also within populations. Complete differentiation and fixation on alternative variants was found for the geographic regions of Sumatra and Borneo by the PCR-RFLP method. The SCAR marker did not amplify in Shorea parvifolia and thus can also be used to distinguish between S. leprosula and S. parvifolia. The marker was successfully amplified from wood DNA extracts suggesting its applicability to track the geographic origin of timber.