Prolactin is an anterior pituitary hormone involved in various physiological phenomenon including reproduction. The prolactin receptor (PRLR) is detected in diverse tissues such as brain, ovary, placenta and uterus in several mammalian species. A total of 227 pigs [Korean native pigs (KNP) 27; Landrace pigs 29; Korean native pigs x Landrace F1 91; Nanchuckmacdon pigs 80] were used to investigate the allele frequency difference of the prolactin receptor (PRLR) gene among the four pig lines. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with Alu I restriction enzyme was used to determine the genotypes of PRLR. Frequencies of PRLR alleles among the four different pig lines were not significantly different (Chi-square=3.94, DF=3, P=0.27). A total of 40 Nanchuckmacdon pigs were used to investigate the effect of the prolactin receptor (PRLR) gene on total number of piglets born (TNB), number of piglets of alive (NBA) using general linear model implemented in MINITAB software. For TNB, the AB genotype had higher genotypic value (10.61) than the values of AA (9.83) and BB (10.30). Likewise, the AB genotype had higher genotypic value (8.96) than the values of AA (8.18) and BB (8.90) for NBA. However, these associations of the PRLR gene with TNB and NBA were not statistically significant. In conclusion, it is necessary to increase the sample size for investigating the effect of the PRLR gene on TNB and NBA in pigs.

Blood types in pigs are divided into two types, A and O type. It is important to select and breed O-type pigs that have no hematologic rejection, because the blood type of the donor is an important factor causing immune rejection in xenotransplantation. Therefore, the gene that determines the blood type is GGTA1(glycoprotein, alpha-1,3-galactosyltransferase 1), which generally belongs to the ABO blood group. This study was carried out to develop a simple and accurate method by analyzing the structure of GGTA1 gene which determines blood type. A primer was designed to allow easy identification of the blood type of the target in the first and second deletion regions of intron 7 to distinguish between the A and O genotypes. That is, for the purpose of identifying the blood type using length difference after the PCR, the forward and reverse primers were designed in the highly conservative region. As a result, a pair of primers were prepared and PCR amplification was performed to distinguish three types of genotypes, AA, AO, and OO, using the length difference by electrophoresis. Using the above primers, the parents and their offspring were compared with each other to confirm the correct genetic pattern. And, in four pig breeds, the genes were amplified and the genotype could be correctly identified. In this study, we could diagnose the blood type of AA, AO, OO genotype of pigs by using primer of INDEL region. Especially, since it is possible to diagnose the genotype by the length difference, it is possible to diagnose it quickly and accurately from the gene amplification to the genotype reading