By Deb Hamernik, ASAS President
Sept. 12, 2016 – Dr. John McEwan gave an invited presentation, “Genomic selection in sheep: where to now?” at the 67th Annual Meeting of the European Federation of Animal Science (EAAP) in Belfast, Ireland, held August 29 – September 2, 2016. More than 1,500 people attended the EAAP annual meeting.
Dr. McEwan has made significant contributions to the international effort to sequence the genomes of cattle and sheep for more than a decade. He also provided leadership for creating high and low density sheep SNP chips (e.g., the 5K, 6K, 15K, 50K, and 600K SNP chips). The sheep industry in New Zealand has been using these SNP chips to allow faster genetic improvement (with improved accuracy) in sheep via whole genome selection since about 2010.
In New Zealand, a monthly across flock and breed national genomic evaluation for more than 20 traits in selected maternal breeds and crosses was implemented. A similar development program is underway in terminal breeds and includes meat-quality traits. McEwan stated that many new technologies are being developed to enhance genomic selection in the future. Precision phenotyping produces a large amount of phenotypic data and offers many potential benefits. For example, scientists would like to collect data on a number of traits associated with fertility, but in natural sheep production situations it is not usually possible for humans to be present and collect data when traits such as estrus, mating, or lambing occur. Scientists are now developing fitbit-like sensors on ear tags that will record and transmit this information to a centralized database.
A better understanding of the genes that regulate feed efficiency and methane production is also needed to decrease the environmental impact of livestock production. McEwan mentioned that the new gene-editing technologies (e.g., CRISPT-Cas9) will require knowledge of DNA function at the individual nucleotide level and this will require higher quality, annotated whole genome sequences, which are not currently available for sheep or cattle. The coordinated international activities of the Functional Annotation of Animal Genome (FAANG) group will help accelerate improvement of high quality, functional annotation of the cattle and sheep genomes. Costs for genome sequencing have decreased significantly in recent years; thus, genotyping by sequencing may now be more affordable than genotyping on SNP chips, especially for less numerous species. For the sheep industry, the desired outcome is parentage, breed prediction, co-ancestry and genomic selection for desired phenotypes or traits at a cost that is equivalent to the current cost of parentage by DNA analysis. If costs of these technologies can be reduced accordingly, then genomic selection will become a routine measurement in ram breeding flocks in New Zealand and perhaps throughout the world.
John McEwan is Principal Scientist, Animal Genomics Team, AgResearch, Invermay Agricultural Centre, New Zealand.