DNA parentage testing is a valuable tool which allows breeders to select elite animals within their stud with confidence, knowing that their ancestry is correct. Breeders can use this information to help fast track genetic progress and confirm parentage when selling elite animals. It increases the validity and value of a pedigree and is essential if estimated breeding values (EBVs) are being used as a basis for selection.
The first year of DNA parentage testing requires the testing of all the dams and sires as well as the progeny, however Genomnz recognises the large outlay involved and offers very competitive prices. In the subsequent years only calves and any bought-in dams will need to be tested. All DNA profiles are stored on the Genomnz database and can be used in at any time for parentage analysis.
The accurate information and production gains that can be achieved will certainly offset the price of DNA testing.
Testing options and requirements
- DNA Profile – basis for all parentage analysis, a DNA profile is generated and stored on our database for future reference
- Pedigree Verification – verify breeders records, a pedigree is suggested by the client and verified or excluded by Genomnz
- DNA Match – determine parents from whole mating or birthing groups, every potential parent must be DNA profiled
- Sire/Dam Match – determine sire or dam from a group of all potential sires/dams, less powerful than full DNA match
How does it work?
Pedigree testing works on the knowledge that every offspring inherits half their genetic information (genes) from their sire and half from their dam. A DNA profile is made up of a panel of informative DNA markers. These markers are regions of DNA that vary in composition between individuals. By taking a “snapshot” of the offspring’s DNA at these markers (the DNA profile), we can compare it with the DNA profiles of the parents. If a variation of one of these markers (genotype) is present in the offspring but absent in the parents then they cannot be the true parents and they are said to be ‘excluded’.
Genomnz, using a proprietary pedigree analysis program, checks the DNA profile of the progeny against all potential parents and determines whether the progeny is excluded from the sire and/or dam. The probabilities of parentage are also calculated if no markers from the panel exclude either parent.
What is the accuracy of the test?
Parentage analysis is an exclusion test, that is, it is 99% accurate if a potential parent is excluded from the progeny. However, DNA alone cannot necessarily determine the true parents. The accuracy of the test therefore refers to its ability to exclude an incorrect parent.
Because parentage analysis is an exclusion test, it is possible to get false matches. A false match is where we fail to exclude an incorrect parent, so the progeny either matches more than one pedigree or matches a parent that is not its true parent. Although rare, there are a number of steps you can take to reduce the chance of a false match including using diverse genetics in your herd and supplying Genomnz with all relevant information.
If you try and match a calf against all the DNA profiles on the Genomnz database there could be several matches. An increase in the number of markers used could help determine a unique match however the cost would also increase proportionately. On farm records such as mating or calving groups, AI and ET records, a complete list of sires used (including backup sires), and a complete list of possible dams will narrow down the number of potential combinations for analysis and will keep the numbers of markers necessary to an affordable cost.
There are a variety of factors that can affect the outcome of the analysis:
- Diversity of the genetic pool – if the sires used are half sibs or the dams are closely related there is an increased likelihood of false matches.
- Missing animals – if the Genomnz database does not hold a DNA profile of all animals involved in the matings a false match may occur where a calf matches a dam that is related to the true dam.
- Sire Match only – a full pedigree test is more powerful than a sire and/or dam match.
While DNA testing is the most accurate tool for parentage recording it is necessary to also provide accurate on farm records.