Narrowing down pig disease genetics in Alberta
Researchers at Canada’s University of Alberta have reported progress in breeding pigs with greater resilience.
The method that is studied focuses on breeding using markers, as that method would be more accurate. In a recent project, Dr Michael Dyck and colleagues focused on how they relate to resilience.
Background to all that is selection solely on genes is not sufficient. After all, while genes related to disease resilience for common diseases like Porcine Reproductive and Respiratory Syndrome (PRRS) have been identified, breeding selection based on these genes is not guaranteed to produce more resilient pigs. That is, gene expression can be affected by the environment, and genes can also interact with other genes, sometimes negatively.
The initiative is funded mainly by PigGen Canada, a non-profit formed by Canada’s pig breeding companies, as well as Genome Alberta.
Using real-world conditions
The team has created what they call the Natural Disease Challenge Model (NDCM) to investigate genomic markers. Dr Dyck described it as “a groundbreaking research framework” that enables disease resilience in pigs to be studied under real-world conditions.
In the approach, pigs in a commercial setting are exposed to multiple pathogens, which is what typically occurs. These pathogens include PRRS virus, influenza A virus, Mycoplasma hyopneumoniae and Streptococcus suis.
Historic research
In the pigs that perform best, DNA is analysed and markers highlighted. In total over 8 years, Dr Dyck and his colleagues have studied the genomes of more than 4,000 pigs using the NDCM model. That could make this research the most comprehensive effort to date to improve pig health.
With over 4,000 pigs studied so far, a huge amount of DNA sequencing data has been collected. The scientists therefore needed a way to organise it and ensure it would be useful. They created what became known as Pig Database (PigDB).
PigDB is available to Dr Dyck and his colleagues, as well as to PigGen members. They are now able to compare traits and gain insight into difficult breeding questions at a level that is not possible with individual herd data. At the same time, PigDB protects the privacy of individual company pig data. Several researchers in Europe have also requested permission to use the dataset and that is being considered.
Wild pig genomes
Genome Alberta, with partners, is funding other genomic research initiatives in agriculture. One of these has the aim of better insight into population genetics and disease resilience of invasive wild pigs, a likely disease vector if African Swine Fever (ASF) were to enter North America.
Sequencing wild boar DNA may reveal genetic differences across populations, where certain genotypes may be found to be more or less susceptible to ASF. This would help tailor disease response strategies in specific regions.
