Email Release Concerning Misconception of DNA Testing
April 13, 2017
On the weekend of April 8-9, a series of posts were put on social media and various blogs discussing the alleged breed make up of a US Hereford sire. This result was supposedly reported by an Australian Hereford Breeder and confirmed by the Australian Hereford Society CEO, Dr. Alex Ball. I had correspondence with Alex over the evening of April 9, and he says that he has not confirmed anything.
The Australian Hereford Society, through the work with Animal Genetics Breeding Unit (AGBU), has been working on a one-step method to include genotypes into their genetic evaluation just as the American Hereford Association (AHA) has been working to adopt Biometric Open Language Tools (BOLT) to do the same. With these methods, parent verification can and will be done on all animals with genotypes to confirm parentage. This fundamental approach will allow all of us to have more confidence in the genetic evaluation because this will make the first step, pedigree, much stronger. In their process, AGBU has looked at breed make-up from a population of genotypes. I am not sure on the size of the population.
The US Meat Animal Research Center (USMARC) has used a similar approach to derive breed composition of animals within the USMARC population and has applied this approach to crossbred animals. One of the main discoveries with this approach was that accurate prediction of breed types was highly dependent upon the animals being used as ‘references’ for the breed. For instance, in the USMARC data, it was very difficult to distinguish between Angus and Red Angus data. Also, if an animal was derived from a breed with no reference animals, it’s breed composition may not be accurate or be misclassified. We do not know what reference animals are being used by AGBU with the Australian Hereford Society, and we do not know whether they are a proxy for AHA animals. Possible differences in reference animals are not necessarily due to breed contamination—genetic selection using EPDs will change the frequencies of genomic regions that are important for the traits under selection. These details relative to breed purity will need to be examined by a broader community.
To summarize, genomics will play a big part in future genetic evaluation work by the AHA. Genomics will allow us to verify parentage and add value to our current genetic evaluations and allow cattlemen to make genetic progress and generational turns much more quickly.
Jack A. Ward