A set of SNP markers for timber tracking of Larix spp. in Europe and Russia
The verification of the geographical origin of timber is of increasing importance with the entry into force of new regulations having become effective (EU Timber Regulation, US Lacey Act and Australia Illegal Logging Prohibition Act) that regulate the trade of timber. Larch timber represents a significant portion of timber traded on the European market. It is mostly harvested in Russia, where trade of illegally harvested timber is known to occur. Although genetic data are available for Larix spp., robust and polymorphic marker tests are still lacking for timber DNA analysis. Using Restriction Site Associated DNA sequencing, we developed a set of 253 SNP loci which was screened on 916 Larix spp. individuals. Bayesian cluster analysis revealed the presence of eight genetic clusters showing a West-East pattern in Eurasia. This marker set resulted in assignment success rates to the region of origin ranging from 74 per cent to 88 per cent. From the full marker set, a subset of 76 loci was selected to allow cost-effective analysis of timber and was successfully tested on nine blind timber samples. The performance of genetic assignment methods and laboratory procedures for the analysis of timber DNA is discussed.