Current Status of Marker-Assisted or Genomic Selection in Hanwoo (Korean cattle) Industry

Korean beef consumers prefer Hanwoo,a Korean native cattle, to US or imported beef breeds due to high intramuscular fat content, thin muscle fibers, minimal connective tissues, and good flavor. Thus, the Hanwoo genome projects have been focused on identification of quantitative trait loci (QTL) or causal variants responsible for growth, meat quality and nutritional components. Whole-genomes (26.5 Gb) of ten individuals were sequenced using a Genome Analyzer IIx and found 2.4 million SNPs including 28K Hanwoo specific SNPs. Some of the SNPs were categorized into the classes related to economic importance such as growth, meat quality, hair, milk production. The bovine Illumina 50K SNP chips were applied to 500 steers to find QTL for carcass and meat quality by whole genome association (WGA) study. The WGA analysis enabled to detect 192 SNPs, which were validated by further association studies using 3,000 Hanwoo steers. To find the SNPs associated with nutritional components including oleic acids as well as palatability, the bovine Affymetrix axiom SNP arrays were used to genotype 640K SNPs for 450 steers. Through GWA analyses, more than 260 SNPs were detected for 75 traits. The significant SNPs will be validated with another Hanwoo samples, in order to implement marker-assisted breeding program. Additional collection of SNP genotypes and phenotypes for the growth, carcass quality and nutritional componentsare necessary to efficiently apply Hanwoo genome selection.