Parentage verification is based on comparing the genetic information of an offspring and the supposed mother(s) and supposed father(s). The genetic variation present in an offspring originates from both parents. Half of the variation originates from the father, with the other half originating from the mother. Tests verifying parentage can be used for multiple species, including animals and humans. For animals, samples such as hair follicles, swabs, blood, semen and various other types of materials can be used to verify parentage. A DNA-profile is determined from each sample. Currently, the most common DNA marker for establishing such a DNA-profile is the STR (Short Tandem Repeat) marker, also referred to as microsatellite. For a few animal species, we also offer the option to verify parentage based on SNP-markers.
The genetic information for each sample is stored in a database and can be shown as a bar code. Each individual has a unique bar code (except in the case of identical twins or cloned animals).
When verifying parentage, the genetic information from an individual is compared with the supposed parents. For a correct parentage, all the genetic information present in an offspring must be present in the combination of the mother and the father. Generally, the test to verify parentage has an accuracy rate of at least 99.5%.
For parentage verification DNA-markers are determined, with one DNA-marker having two variants (referred to as alleles). One allele originates from the father, while the other originates from the mother. By accurately visualising a sufficient number of alleles, it can be determined whether alleles (DNA variants) appear in the offspring that are not found in the supposed parents. If all of the offspring’s DNA variants are present in the parents, the reliability of the test can be statistically established.
The result of a parentage or identification verification is limited to the question being asked. Generally, the result is based on a large number of DNA markers, with the result being over 99.5% reliable when both parents’ DNA is included in the test. The probability that a wrong parentage would not be identified is extremely low. The reliability is reduced e.g. if the DNA of one of the parents is not included in the test or if the DNA-profile of a parent must be reconstructed. The reliability is also influenced by the genetic variation in the population. The DNA-markers that are used for verifying the parentage and for identification do not provide any information regarding characteristics such as coat colour and quality or about the presence or absence of genetic diseases.
Some breeding animals are extremely valuable because of their external characteristics. There are a number of methods available for identifying these animals, such as tattoos, chips and ear tags. In some cases, however, it may be important to determine a DNA profile so that these animals can also be identified even without employing these methods. This could prove necessary when the animal is stolen, an ear tag is lost or a chip becomes unreadable.
Once the alleles are determined for a number of DNA markers, a DNA-profile is determined for the individual being tested. This DNA-profile is unique to a certain animal; if doubts as to the animal’s identity arise, the DNA-profile can be determined again to confirm the animal’s identity. The DNA-profile of an animal is the same in every part of its body, which means that a DNA-profile can be determined regardless of what type of sample material the DNA originates from, such as hair follicles, swabs, blood, semen or other tissue.
Because there is a lot of variation between individuals’ DNA-profiles, there is no chance that two random, unrelated individuals would have identical bar codes. Each individual will have his or her own DNA-profile which will differ, in one or more markers, from that of other animals. Obvious exceptions to this are identical twins and cloned animals, who have completely identical DNA-profiles.
The legal DNA-test differs in a number of ways from an ‘ordinary’ parentage verification or identity check. Besides an additional statistical calculation and a more extensive report, the rules regarding obtaining and securing sample materials are different. The ‘chain of custody’ of the sample is very important and must be recorded. This means that every step of the process, from obtaining the sample to reporting the result, must be documented and double checked. As a consequence, these tests are more expensive than an ordinary tests. Please be sure to contact us beforehand if you believe you may need to have a legal DNA-test performed. It is not always possible to meet the requirements for a legal-DNA test afterwards.