Footprints of recent selection and variability in breed composition in the Göttingen Minipig genome

The Göttingen Minipig (GMP) developed at the University of Göttingen is a synthetic breed that is widely used in medical research and toxicology. It combines the high fertility of the Vietnamese potbellied pig, the low body weight of the Minnesota Minipig and the white coat colour of the German Landrace pig. The aim of this study was to find genomic regions that may have undergone selection since the creation of the breed in the 1960s. Therefore, the whole genome was screened for footprints of recent selection based on single nucleotide polymorphism (SNP) genotypes from the Illumina Porcine SNP60 BeadChip using two methods: the extended haplotype homozygosity (EHH) test and the estimation of the genomic proportion of the three original breeds at each SNP using a Bayesian approach. Local deviations from the average genome‐wide breed composition were tested with a permutation‐based empirical test. Results for a comprehensive whole‐genome scan for both methods are presented. Several regions showing the highest P‐values in the EHH test are related to breeding goals relevant in the GMP, such as growth (SOCS2, TXN, DDR2 and GRB10 genes) and white colour (PRLR gene). Additionally, the calculated proportion of the founder breeds diverged significantly in many regions from the pedigree‐based expectations and the genome average. The results provide a genome‐wide map of selection signatures in the GMP, which leads to a better understanding of selection that took place over the last decades in GMP breed development.     

Extensive changes in innate immune gene expression in obese Göttingen minipigs do not lead to changes in concentrations of circulating cytokines and acute phase proteins

The usefulness of Göttingen minipigs as models for obesity and obesity‐related pathologies is well established. The low‐grade inflammation associated with obesity involves a range of innate immune factors; however, to our knowledge, the impact of obesity on innate immune factor expression has not been studied in Göttingen minipigs. Therefore, we studied the expression of innate immune genes in liver and adipose tissues as well as serum concentrations of cytokines and acute phase proteins in obese vs. lean Göttingen minipigs. In the liver, of 35 investigated genes, the expression of nine was significantly different in obese pigs (three up‐regulated, six down‐regulated). Of 33 genes in adipose tissues, obesity was associated with changed expression of 12 genes in the visceral adipose tissue (VAT) (three up‐regulated), 11 in the abdominal retroperitoneal adipose tissue (RPAT) (seven of these up‐regulated) and eight in the subcutaneous adipose tissue (SAT) from the neck (five of which were up‐regulated). Obesity‐associated expression changes were observed for three genes in all adipose tissues, namely chemokine (C‐C motif) ligand 3‐like 1 (up‐regulated), CD200 molecule (down‐regulated) and interleukin 1 receptor antagonist (up‐regulated) with interleukin 1 receptor antagonist being the most highly regulated gene in both VAT and RPAT. Looking at patterns of expression across the three types of adipose tissues, obesity was associated with an increased number of acute phase proteins differentially expressed between adipose tissues and a decreased tissue‐specific expression of cytokines and chemokines. In contrast to obese humans, no changes in serum concentrations of haptoglobin, C‐reactive protein, serum amyloid A, tumor necrosis factor‐α and interleukin 6 were found in obese Göttingen minipigs.