- Species Identification
- Sex Identification
- Individual Identification
- Population Assignment
- Parentage Analysis
Species identification is performed using mitochondrial DNA markers that are conserved within a species but variable between species. DNA is used to identify and confirm the species of origin of items suspected of being involved in illegal commercialisation or illegal trade as defined by the CITES convention. By comparing the sequences obtained at these markers with those of known controls we can determine, with up to 99 percent confidence, the species of origin. Individual species present in mixed meat products such has sausages can also be resolved to determine if specific species are being illegally processed.
When items lack sex-specific morphological characteristics, examination of the X and Y chromosome specific DNA can establish an animal’s gender. This process is routinely used to determine the sex of an animal using materials such as blood, hair or muscle as well as several other types of biological materials.Mammals: DNA from evidence items are examined at a region of the Zfx/Zfy genes on the X and Y-chromosomes and a region of the sry gene on the Y-chromosome. Thus females exhibit a single Zfx gene from the two X chromosomes where as males would show two gene products from each of the Zfy and male specific sry genes.Birds: Examination of the Z and W chromosome-specific CDH (chromo-helicase binding protein) gene allows the determination of the sex of a number of bird species, including falcons, common eiders and turkey. In birds it is the females, rather than males, that exhibit heterogamety.
Short tandem repeat (STR) analysis is carried out for purposes of individual identification, assignment of population of origin and parentage determination. STRs are stretches of short repeated DNA sequences that are highly polymorphic. These differences can be detected and thus used to establish the individual identity of an animal. DNA from evidence items is analysed using a species specific array of STRs. If two evidence items exhibit the same pattern of STRs, then the probability of the samples originating from the same individual is calculated based on the most frequent alleles present in a DNA database from the species of interest. Our laboratory has established databases for the most common species that we work with such as moose and deer from several provinces. We can also establish new databases for novel species as the need arises.
Population identification has proven important in the prosecution of cases where an animal is being claimed as originating from one geographic region but is suspected to have been taken from another, where hunting may not have been permitted. This analysis has been carried out for Ontario moose, Newfoundland caribou and several populations of walleye from various lakes in Ontario.
Parentage analysis is often performed to determine if captive bred animals are the legal offspring of registered breeding pairs or if animals have been illegally obtained from wild stocks. Other cases that have been handled by the lab requested testing to confirm a sibling relationship between a number of animals thought to be from the same litter.
Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, seawater, snow or even air rather than directly sampled from an individual organism. As various organisms interact with the environment, DNA is expelled and accumulates in their surroundings.