Background
The most applied method for origin verification is based on genetic differences between trees. Genetic methods operate on the principle that genetically related trees are also geographically closer. The method has high potential for verification of individual trees (DNA fingerprinting) as well as for origin verification based on population genetics. For several timber species genetic reference databases are already available and the method has shown potential for small spatial scales.
DNA markers
In genetic analyses of timber several methods are available and which one is used depends on availability of reference material and on the question at hand. The following methods have been applied to timber:
- DNA barcoding, mainly for species identification
- Microsatellite markers (SRRs), for origin identification
- SNPs (Single Nucleotide Polymorphisms), for origin identification
At Timtrace we focus on origin identification. We have experience in using both microsattelites and SNPs. Both of these methods rely on small ‘copying errors’ leading to gradual differences in the genome among trees of the same species. As these errors are inherited by offspring they give an indication of kinship among trees. This can then be used to characterize populations of trees at a local level.