A broad analysis of organisms is possible using molecular DNA as a marker. Mitochondrial genome and genes present in mtDNA, e.g. cytochrome b gene, are widely used in investigations and the significance of this research is becoming increasing. This gene is coded by heavy (H) strand of mtDNA. Cytochrome b is one of 11 subunits composed of bc1 complex of respiratory chain of mitochondria, the sequence of which is written down in the mitochondrial genome. Cytochrome b gene traits are a slow rate of variations during evolution, the presence of some parts of the gene that are more conserved and those which show high divergence rates. Those traits make the cytochrome b gene useful as a marker in many analyses. The cytochrome b gene is used as a tool in such studies as: legal and veterinary medicine, palaeontology, as well as phylogenetics, and it can attain the status of a universal metric.
Genetic markers in mitochondrial and chloroplast DNA were analysed to determine the native status and possibly trace the origin of the silver fir (Abies alba Mill.) growing outside this species natural range in Osusznica Forest District (northern Poland). The provenance of the extralimital populations were determined through comparison with reference samples from the native range of silver fir in Poland and Ukraine. Our results suggest that the Sudety Mts. are the most probable region of the origin of fir from Osusznica. It also seems that the plus seed stands in Osusznica can be treated as a valuable archive of the genetic resources of the fir from the Sudety and, if necessary, may support program of this species restitution.