The purpose of this study was to assess the genetic variation and establish the relationship amongst breeds and strains using 15 chicken specific microsatellite markers. A total of 285 unrelated DNA samples from four Korean native chicken strains (Black strain of Korean native chicken; KL, Red Brown strain of Korean native chicken; KR, Ogol strain of Korean native chicken; KS and Yellow Brown strain of Korean native chicken; KY) and three introduced chicken breeds (F strain of White Leghorn; LF, K strain of White Leghorn; LK, Rhode Island Red; RC and Cornish; CN) were genotyped to estimate within and between breed genetic diversity indices. All the loci analyzed in 15 microsatellite markers showed a polymorphic pattern and the number of alleles ranged from 5 to 14. The polymorphism information content (PIC) of UMA1019 was the highest (0.872) and that of ADL0234 was the lowest (0.562). The expected total heterozygosity (He) within breed and mean number of observed alleles ranged from 0.540 (LF) to 0.689 (KY), and from 3.47 (LK) to 6.07 (KR), respectively. The genetic variation of KR and KY were the highest and the lowest within Korean native strains, respectively. The genetic distance results showed that Korean native chicken strains were separated with the three introduced chicken breeds clustered into another group. The lowest distance (0.149) was observed between the KR and KL breeds and the highest distance (0.855) between the KR and LK breeds. The microsatellite polymorphism data were shown to be useful for assessing the genetic relationship between Korean native strains and other foreign breeds.

The effects of diacylglycerol O-acyltransferase (DGAT1) candidate gene polymorphism on the economic traits of Hanwoo were studied. Through sequencing analysis, two polymorphism sites at K232A and T11993C were established and were analyzed by PCR-RFLP. The PCR-RFLP analysis for K232A showed that the frequencies of alleles K and A were 0.75 and 0.25, respectively, and the frequencies of genotypes for K/K, K/A and A/A were estimated as 0.509, 0.491 and 0, respectively. In the PCR-RFLP analysis for T11993C, we found allele frequencies of 0.773 and 0.227 for T and A, respectively, and 0.546, 0.454 and 0 for the T/T, T/C and C/C genotype frequencies, respectively. No significant effects on economic traits in Hanwoo were found in the separate analysis of K232A and T11993C polymorphisms, but the interaction between K232A and T11993C showed a significant effect (p<0.005) on marbling score. The DGAT1 candidate gene was found to have a significant effect not only on milk yield and component traits but also on the metabolism of intramuscular fat.