The objective of this study was to find out candidate genes associated with litter size trait in pigs of inbred Large Yorkshire and Landrace populations. 86 sows were screened for candidate genotypes along with litter size data recordings. Association of litter size with genotypes of candidate genes were investigated to verify the usefulness of each gene's genotypes as markers for the trait. For the lines of Large Yorkshire, PRLR3 and RBP4 genes were genotyped. Frequency distribution of PRLR3 with genotypes AA, AB and BB were each 0.14, 0.44 and 0.42. And the average litter size by PRLR3 genotypes were 8.83, 10.81 and 10.70 piglets per litter, the average estimated breeding values of which were 0.243, 0.332, 0.365, respectively for AA, AB and BB genotypes. Genotypic frequencies of RBP4 by AA, AB and BB genotypes were 0.10, 0.44 and 0.46. The average litter size by genotypes of RBP4 were 10.40, 10.57 and 10.35 piglets per litter and their corresponding average estimated breeding values were 0.451, 0.353 and 0.261, respectively for genotypes AA, AB and BB. Significance in differences among genotypes were not observed, but B allele of RBP4 seems to be associated with litter size. In Landrace lines, frequencies of RBP4 genotypes, AA, AB and BB were 0.29, 0.55 and 0.16. And the average litter size of these genotypes were 10.50, 11.08 and 11.00 piglets per litter. The corresponding averages of estimated breeding values of each genotypes were 0.172, 0.135 and 0.104. In Landrace lines, allele A was more likely to be associated with litter size, even if differences among average litter size were not significant. We conclude that genotyping of two candidate genes is a helpful tool to identify genetic potentials of litter size in pigs.

This study aims to identify DNA marker related to health index which is derived from fatty acid composition of Hanwoo meat. We investigated a genetic association between two SNPs (-867G>C and 878C>T) of SCD gene and health indexes. Two health index values (index of atherogenicity and index of thrombogenicity) were derived from a combination of fatty acid composition. Phenotypic correlation indicated that oleic acid (C18:1) was negatively correlated to index of atherogenicity (-0.84) and index of thrombogenicity (-0.91), respectively. Statistical analysis revealed that 878T>C SNP was significantly associated with IA (index of atherogenicity, p=0.012) and IT (index of thrombogenicity, p=0.006). There was no association between the regulatory SNPs (-867G>C and -877Gdel) and health indexes. Haplotype analysis detected 4 main haplotype (GdelT; 0.004, GdelC; 0.344, CGT; 0.350 and CGC; 0.261) in Hanwoo. The GdelT haplotype was significant on IA and IT. The effect of GdelT haplotype showed increasing IA and IT values, while GdelC haplotype has a decreasing IA and IT value in Hanwoo. In conclusion, the 878C>T SNP in the SCD gene seems to have an effect on this health index and might be implemented into animal breeding program.

As an experimental reference population, crosses between Korean native pig and Landrace were established and information on seven meat quality traits was recorded. Animals were genotyped for 24 microsatellite markers covering hromosomes 2, 6, and 7 for pa