The insulin-like growth factor binding proteins (IGFBPs) is involved in the regulating effects and the biological activities of the insulin-like growth factors (IGFs). Recently, It has been reported that the IGFBP2 gene polymorphism was associated growth and skeletal development in chicken. This study was designed to investigate the association of the C1032T SNP of IGFBP2 gene with growth and egg production traits in Korean native chicken (KNC) population as well as other chicken breeds. A total of 225 chickens from the three breeds (Rhode Island Red, Cornish, Leghorn) and 245 chickens from the six strains of Korean native chickens including Black, Gray, Ogol, Red, White, and Yellow, were genotyped by PCR-RFLP (polymerase chain reaction-restricted fragment length polymorphism) and analyzed the association between their genotypes and economic traits by SAS program. The results showed that the SNP (single nucleotide polymorphism) was significantly associated with multiple traits, including body weight of 150 days (p<0.001 and p<0.05) in the Rhode Island Red and the KNC (White) and egg production number (p<0.05) in the KNC (Black) breed. These results suggest that IGFBP2 C1032T SNP could be used as a DNA marker for the improvement of economic traits in Korean native chicken breeding.

This study was conducted to elucidate the genetic relationships among native Korean cattle breeds by analyzing genetic variations and distances. Relationships among Hanwoo, Korean brindle, Korean black, Jeju black, and Holstein cattle were evaluated using 15 microsatellite markers. Korean brindle and Korean black cattle had the closest relationship based on the lowest genetic distance being observed between these breeds. A Neighbor-Net tree created using the Reynolds distances indicated that Korean brindle and black cattle formed a group separate from the Hanwoo population. However, an Fst pairwise test revealed that Hanwoo, Korean brindle, and Korean black cattle differed significantly (P <0.01). Moreover, the results of this study confirmed that Jeju black cattle became a separate established breed in Korea through a path different from that of cattle from inland regions, even though it is considered to be a Korean native breed. Overall, the results of our study indicate that Korean brindle and black cattle are indeed native Korean breeds that maintain an endangered status.