Evaluation of the suitability of mitochondrial DNA for species identification of microtraces and forensic traces

Abstract

The objective of the study was to demonstrate how mitochondrial DNA (mtDNA) can be used to determine the species origin of animal microtraces. The study included pieces of cat and dog hair without the root, a fragment of cooked chicken bone (0.1g), three goose down samples (0.028 g), a pork swab, a pork scratching (5×5×5 mm), and pork lard (0.22 g). DNA was isolated from all of these samples using the method appropriate for the particular source material. The extracts had DNA concentration exceeding 5.4 ng/µl with A purity range of 1.14-1.88. Next, the samples were subjected to PCR and real-time PCR with species-specific primers and primers complementary to mitochondrial DNA (mtDNA). Control reactions based on the amplification of eukaryotic-specific fragment (18S rRNA) were additionally performed. PCR and real-time PCR products for detection of species-specific mtDNA were obtained for all templates, whereas during the detection of eukaryote DNA no product was obtained for dog and cat hair only. The poor quality of the obtained DNA did not prevent the analysis. The results showed that mitochondrial DNA is suitable for identification of small or highly processed samples, in which genomic DNA often cannot be analyzed.

Forensic DNA Analysis

“…The assay worked well with low levels of DNA template and could be useful in screening samples containing DNA from unknown animal origin . Another study examined the potential use of mtDNA markers for species identification of trace levels of biological materials when autosomal DNA was too low for detection …”

“…157 Another study examined the potential use of mtDNA markers for species identification of trace levels of biological materials when autosomal DNA was too low for detection. 158 A 16 loci short tandem repeat (STR) system recommended by International Society for Animal Genetics (ISAG) was used to successfully genotype 1421 domestic pigeons (Columba livia domestica). Due to the difficulty in determining the sex of an adult bird, a sexing marker was added to the panel as an extra quality control.…”

Detection of the Species Composition of Food Using Mitochondrial DNA: Challenges and Possibilities of a Modern Laboratory

“…In animals, it is slightly over 16,000 bp, which means it is relatively easy to develop methods for identifying the panel of organisms chosen by a researcher. Current research papers present several methods from identify single farm species such as pigs [7][8][9], cattle [7][8][9][10], sheep [7], horses [9,11], chickens [9,12], turkeys [9], ducks [8,13], fish [14] to less common animals like kangaroos [15], snails [16], and marine animals like octopuses [17], shrimp [18] and sharks [19]. This is relatively the simplest method of analysis.…”

“…It often happens that the matrices in which DNA is sought have a form that prevents its biological origin to be clearly identified, and so it may become a source of potential problems. This is exemplified by a fragment of biological material found by a consumer in meatballs [13]. The object concerned, which was small in size and additionally resembled a human nail (Figure 1), was identified during the analysis as material coming from one of the breeding species, so its presence in food preparations was fully justified.…”