Insects and animals can recognize surrounding environments by detecting thousands of chemical odorants. Olfaction is a complicated process that begins in the olfactory epithelium with the specific binding of volatile odorant molecules to dedicated olfactory receptors (ORs). OR proteins are encoded by the largest gene superfamily in the mammalian genome. We report here the whole genome analysis of the olfactory receptor genes of S. scrofa using conserved OR gene specific motifs and known OR protein sequences from diverse species. We identified 1,301 OR related sequences from the S. scrofa genome including 1,113 functional OR genes and 188 pseudogenes. OR genes were located in 46 different regions on 16 pig chromosomes. We classified the ORs into 17 families, three Class I and 14 Class II families, and further grouped them into 349 subfamilies. We also identified inter- and intra-chromosomal duplications of OR genes residing on 11 chromosomes. A significant number of pig OR genes (n=212) showed less than 60% amino acid sequence similarity to known OR genes of other species. We also performed a similar analysis on the cattle OR subgenome and identified 1,071 OR related sequences. We show that S. scrofa has one of the largest OR repertoires, suggesting an expansion of OR genes in the swine genome. Considering available information from literature, it seems that OR systems between mammals and insects possess high similarity in their action mechanisms and rapid evolutionary changes due to differences in living environments.

In this study, we examined whether Hanganutziu‐Deicher (H‐D) antigens are important as an immunogenic non‐a1,3‐galactose (Gal) epitope in pigs with a disrupted a1,3‐ galactosyltransferase gene. The targeting efficiency of the AO blood genotype was achieved (2.2%) in pig fibroblast cells. A total of 1800 somatic cell nuclear transfer (SCNT) embryos were transferred to 10 recipients. One recipient developed to term and naturally delivered two piglets. The a1,3‐galactosyltransferase activity in lung, liver, spleen, and testis of heterozygote a1,3‐galactosyltransferase gene knockout (GalT‐KO) pigs was significantly decreased, whereas brain and heart showed very low decreasing levels of a1,3‐ galactosyltransferase activity when compared to those of control. Enzyme‐linked lectinosorbent assay showed that the heterozygote GalT‐KO pig had more sialyla2,6‐ and sialyla2,3‐ linked glycan than the control. Furthermore, the heart, liver, and kidney of the heterozygote GalT‐KO pig had a higher N‐glycolylneuraminic acid (Neu5Gc) content than the control, whereas the lung of the heterozygote GalT‐KO pig had Neu5Gc content similar to the control. Collectively, the data strongly indicated that Neu5Gc is a more critical xenoantigen to overcoming the next acute immune rejection in pig to human xenotransplantation.

Insulin-like growth factor II (IGF2) and H19 genes are mutually imprinted genes which may be responsible for abnormalities in the cloned fetuses and offspring. This study was performed to identify putative differentially methylated regions (DMRs) of porcine H19 locus and to explore its genomic imprinting in in vitro fertilized (IVF) and somatic cell nuclear transferred (SCNT) embryos. Based on mice genomic data, we identified DMRs on H19 and found porcine H19 DMRs that included three CTCF binding sites. Methylation patterns in IVF and SCNT embryos at the 2-, 4-, 8～16-cells and blastocyst stages were analyzed by BS (Bisulfite Sequencing)-PCR. The CpGs in CTCF1 was significantly unmethylated in the 2-cell stage IVF embryos. However, the 4- (29.1%) and 8～16-cell (68.2%) and blastocyst (48.2%) stages showed higher methylation levels (p<0.01). On the other hand, SCNT embryos were unmethylayted (0～2%) at all stages of development. The CpGs in CTCF2 showed almost unmethylation levels at the 2-, 4- and 8～16-cell and blastocyst stages of development in both IVF (0～14.1%) and SCNT (0～6.4%) embryos. At all stages of development, CTCF3 was unmethylated in IVF (0～17.3%) and SCNT (0～1.2%) embryos except at the blastocyst stage (54.5%) of IVF embryos. In conclusion, porcine SCNT embryos showed an aberrant methylation pattern comprised to IVF embryos. Therefore, we suggest that the aberrant methylation pattern of H19 loci may be a reason for increased abnormal fetus after embryo transfer of porcine SCNT embryos.