Search

The mitogen-activated protein kinase 8 (MAPK8), resistin (RETN), 11 beta hydroxysteroid dehydrogenase isoform 1 (HSD11B1) and protein kinase B Akt2 (AKT2) genes are all genes known to affect insulin signalling and have been implicated in the progression of obesity and type 2 diabetes in humans. In this study, polymorphisms in the porcine diabetes related MAPK8, RETN, HSD11B1 and AKT2 genes were identified, mapped and their associations with phenotypic measurements in swine were analysed. Polymorphisms detected in the MAPK8, RETN and HSD11B1 loci were used to genotype a Berkshire-Yorkshire pig breed reference family. Using linkage analysis, RETN, HSD11B1 and MAPK8 genes were mapped to pig chromosomes 2, 9 and 14, respectively, while the AKT2 gene was physically mapped to pig chromosome 6q21. Results presented here suggest associations between the polymorphisms in the MAPK8, RETN and HSD11B1 genes with several phenotypic measurements, including fat deposition traits in the pig. Because these genes have been implicated in obesity and diabetes in humans, and this study suggests associations with fat related traits, further research on these genes in swine may provide useful information on genetic factors underlying lean pork production.

Body mass (BM) and resting metabolic rates (RMR) are two inexorably linked traits strongly related to mammalian life histories. Yet, there have been no studies attempting to estimate heritable variation and covariation of BM and RMR in natural populations. We used a marker-based approach to construct a pedigree and then the 'animal model' to estimate narrow sense heritability ( h2) of these traits in a free-living population of weasels Mustela nivalis-a small carnivore characterised by a wide range of BM and extremely high RMR. The most important factors affecting BM of weasels were sex and habitat type, whereas RMR was significantly affected only by seasonal variation of this trait. All environmental factors had only small effect on estimates of additive genetic variance of both BM and RMR. The amount of additive genetic variance associated with BM and estimates of heritability were high and significant in males ( h2 = 0.61), but low and not significant in females ( h2 = 0.32), probably due to small sample size for the latter sex. The results from the two-trait model revealed significant phenotypic (r P = 0.62) and genetic correlation (r A = 0.89) between BM and whole body RMR. The estimate of heritability of whole body RMR (0.54) and BM corrected RMR (0.45) were lower than estimates of heritability for BM. Both phenotypic and genetic correlations between BM corrected RMR and BM had negative signals (r P = −0.42 and r A = −0.58). Our results indicate that total energy expenditures of individuals can quickly evolve through concerted changes in BM and RMR. [ABSTRACT FROM AUTHOR]

Contents We carried out an SNP discovery project in pigs for candidate genes playing potentially important roles in embryonic development. Using eight pigs one each from eight breeds (Meishan, Mangalitza, Duroc, Pietrain, German Landrace, Hampshire, Husum Red Pied, German Large White), 36 SNPs were identified in intronic sequences of 21 porcine candidate genes based on sequencing of PCR products. The primer pairs were designed using porcine EST sequences allowing amplification of introns. These SNPs were tested for their association with the number of piglets born alive in German Large White sows using a discordant approach. Significant effects (p < 0.001 and p < 0.05, respectively) of intronic SNPs on litter size were found for four genes: mitogen-activated protein kinase kinase kinase 3 ( MAP3K3), vascular endothelial growth factor receptor ( KDR), erbb2 interacting protein ( ERBB2IP) and peroxisome proliferator-activated receptor delta ( PPARD). These SNPs can be further tested in upcoming association studies for their influence on litter size in different breeds using larger sample sizes. [ABSTRACT FROM AUTHOR]

To be effective, management programmes geared towards halting or reversing the spread of invasive species must focus on defined and defensible areas. This requires knowledge of the dispersal of non-native species targeted for control to better understand invasion and recolonisation scenarios. We investigated the genetic structure of invasive American mink ( Neovison vison) in Scotland, and incorporated landscape genetic approaches to examine resultant patterns in relation to geographical features that may influence dispersal. Populations of mink sampled from 10 sites in two regions (Argyll and Northeast Scotland) show a distinct genetic structure. First, the majority of pairwise population comparisons yielded FST values that were significantly greater than zero. Second,amova revealed that most of the genetic variance was attributable to differences among regions. Assignment tests placed 89 or more of individuals into their sampled region. Bayesian clustering methods grouped samples into two clusters according to their region of origin. Wombling approach identified the Cairngorms Mountains as a major impediment to gene flow between the regions. Mantel pairwise correlations between genetic and geographical distances estimated as least-cost distance assuming a linear increase in the cost of movement with increasing elevation were higher than Euclidean distances or distance along waterways. Spatial autocorrelation analyses revealed stronger spatial structuring for females than for males. These results suggest that gene flow by American mink is restricted by landscape features (mountain ranges) and that eradication attempt should in the first instance break down the connectivity between management units separated by mountains. [ABSTRACT FROM AUTHOR]