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The American mink (Neovison vison) is an invasive species of mustelid, native to North America, first reported in Chiloé Island, Chile, in 2013. Due to the known threats of this exotic species on native and domestic fauna, as well as on humans (e.g., depredation and reservoir of diseases such as leptospirosis and COVID-19), great efforts have been made to control and eradicate their populations in Chiloé. Nonetheless, the genetic and epidemiological status of its current population is unknown. Here, we assessed genetic diversity, structure, and presence of Leptospira spp. in N. vison populations from Chiloé. To achieve this, we genotyped 61 individuals across 12 locations on the island and compared them to 30 individuals from 6 locations on the mainland using 12 microsatellite markers. High genetic diversity (He: 0.68), low genetic structure (FST: 0.021), high genetic flow (Nm: 7.43), and five shared genotypic groups were detected between continent and island mink populations. Although these results suggest multiple routes and origins of invasion from the continent to Chiloé, high migration rates detected between island and Pargua localities allow us to infer that a large number of individuals crossed the Chacao Channel. On the other hand, leptospirosis assays on 33 mink kidney samples using qPCR detected this pathogen with a prevalence of 18% in 42% of the localities sampled (6 individuals from 5 localities). We hope that this first population genetic and epidemiological report will be a useful tool for decision-making and the control of minks on Chiloé Island. [ABSTRACT FROM AUTHOR]

American marten were extirpated from much of their native range in the northeastern United States as a result of land development and overharvesting before the mid-twentieth century. Based on occurrence records, recolonization in the late twentieth century was believed to have occurred via natural population expansion from two refugia: northern Maine and the eastern Adirondack Mountains of New York. Furthermore, a 1989-1991 reintroduction attempt in southern Vermont was originally declared unsuccessful, but marten have been rediscovered in southern Vermont since 2010. We used molecular techniques to resolve uncertain population histories and estimate contemporary levels of genetic variation and gene flow in marten populations in the northeastern United States. We sequenced a 320 bp segment of the control region (D-loop) of mtDNA in 112 individuals and amplified 10 microsatellite loci in 111 individuals. Five genetic clusters were identified in the northeastern United States based on the microsatellite data: (1) Maine, (2) New Hampshire, (3) eastern Adirondacks (New York), (4) western Adirondacks (New York), and (5) southern Vermont. Clustering and assignment tests suggest that individuals in southern Vermont are most likely to have originated in Maine—the primary source of the reintroduction. However, we were unable to rule out the possibility of a relict population in southern Vermont. Population expansion in New Hampshire appears to be the primary source of recolonization in northeastern Vermont. Additionally, dispersers from the reintroduction attempt may have spread to northeastern Vermont. Genetic diversity is lower in the entire northeastern United States than an interior population in Ontario, Canada. This study improves our understanding of population history in the northeastern United States. Relict populations of marten may have persisted through the nineteenth and twentieth centuries where they were believed to have been extirpated. Recognizing and conserving all of the distinct subsets of native genetic diversity in the region could promote long-term population health. [ABSTRACT FROM AUTHOR]

Attempts to mitigate the impact of invasive species on native ecosystems increasingly target large land masses where control, rather than eradication, is the management objective. Depressing numbers of invasive species to a level where their impact on native biodiversity is tolerable requires overcoming the impact of compensatory immigration from non-controlled portions of the landscape. Because of the expected scale-dependency of dispersal, the overall size of invasive species management areas relative to the dispersal ability of the controlled species will determine the size of any effectively conserved core area unaffected by immigration from surrounding areas. However, when dispersal is male-biased, as in many mammalian invasive carnivores, males may be overrepresented amongst immigrants, reducing the potential growth rate of invasive species populations in re-invaded areas. Using data collected from a project that gradually imposed spatially comprehensive control on invasive American mink ( Neovison vison) over a 10,000 km area of NE Scotland, we show that mink captures were reduced to almost zero in 3 years, whilst there was a threefold increase in the proportion of male immigrants. Dispersal was often long distance and linking adjacent river catchments, asymptoting at 38 and 31 km for males and females respectively. Breeding and dispersal were spatially heterogeneous, with 40 % of river sections accounting for most captures of juvenile (85 %), adult female (65 %) and immigrant (57 %) mink. Concentrating control effort on such areas, so as to turn them into 'attractive dispersal sinks' could make a disproportionate contribution to the management of recurrent re-invasion of mainland invasive species management areas. [ABSTRACT FROM AUTHOR]

In general, landscape genetic studies have ignored the potential role that the phenotype of individuals plays in determining fine-scale genetic structure in species. This potential over-simplification ignores an important component that dispersal is both condition- and phenotype-dependent. In order to investigate the relationship between potential dispersal, habitat selection and phenotype, we examined the spatial ecology, body mass and fine-scale genetic structure of weasels ( Mustela nivalis) in Białowieża Forest in Poland. Our study population is characterized by an almost three-fold phenotypic variation in adult body mass and weasels were segregated in certain habitats according to size. We detected significant genetic structuring associated with habitat within the studied area and analyses of radio-tracking and re-capture data showed that the maximum extent of movement was achieved by weasels of medium body size, whereas the smallest and largest individuals exhibited higher site fidelity. With the unrestricted movement of the medium-sized individuals across optimal habitat, genetic admixture does occur. However, the presence of a barrier leads to unidirectional gene flow, with larger individuals outcompeting smaller individuals and therefore maintaining the genetic break in the study area. This highlights the importance of considering both intrinsic (phenotype) and extrinsic (environmental) factors in understanding dispersal patterns and ultimately, gene flow in complex landscapes. [ABSTRACT FROM AUTHOR]

Landscape heterogeneity can influence animal dispersal by causing a directional bias in dispersal rate, as certain landscape configurations might promote, impede, or prevent movement and gene flow. In forested landscapes, logging operations often contribute to heterogeneity that can reduce functional connectivity for some species. American martens ( Martes americana) are one such species, as they are considered specialists of late-seral coniferous forests. We assessed marten gene flow to test the hypothesis that habitat management has maintained landscape connectivity for martens in the managed forests of Ontario, Canada. We genotyped 653 martens at 12 microsatellite loci, sampled from 29 sites across Ontario. We expected that if forest management has an effect on marten gene flow, we would see a correlation between effective resistance, estimated by circuit theory, and genetic distance, estimated by population graphs. Although we found a positive relationship between effective resistance and genetic distance (Mantel r = 0.249, P < 0.001), marten gene flow was better described by isolation by Euclidean distance (Mantel r = 0.410, P < 0.001). Our results suggest that managed forests in Ontario are well connected for marten and neither impede nor promote marten gene flow at the provincial scale. [ABSTRACT FROM AUTHOR]

We investigated the feasibility of using genetic techniques to census pine marten ( Martes martes) populations by genotyping non-invasively collected samples (plucked hair and scats), with particular reference to the genetically depauperate Irish population. Novel real-time polymerase chain reaction methods were developed for species and sex identification, targeting short DNA sequences. Background genetic variation at 17 microsatellite loci was very low in the Irish population, with an average of 2.29 alleles per locus and expected heterozygosity of 0.35. Despite such low polymorphism, a panel of eight loci with a sibling probability of identity of 0.011 reliably identified individual pine marten and their gender, as determined by reference to genotypes of live trapped individuals. With high nuclear DNA amplification success rates (93.8%) and low genotyping error rates (1.8%), plucked hairs may represent a more reliable and cost-effective DNA source than scats for monitoring populations of this elusive carnivore, and similar taxa such as the sympatric stone marten Martes foina. [ABSTRACT FROM AUTHOR]

Abstract  Multiplex Polymerase chain reaction (PCR) is the term used when more than one pair of primers is used in a polymerase chain reaction. The goal of multiplex PCR is to amplify several segments of target DNA simultaneously and thereby to conserve template DNA, save time, and minimize expense. The success of the experiment is dependent on primer design. However, this can be a dreary task as there are many constrains such as melting temperatures, primer length, GC content and complementarity that need to be optimized to obtain a good PCR product. In our investigations, we found few primer design tools for multiplex PCR and there was no suitable tool for our partners who want to use a multiplex PCR genotypic assay. The tool draws on a genetic algorithm where stochastic approaches based on the concept of biological evolution, biological genetics and genetic operations on chromosomes are used to find an optimal solution for multiplex PCR. The presented experimental results indicate that the proposed algorithm is able to find a set of primer pairs that not only obey the design properties but also work in the same tube. [ABSTRACT FROM AUTHOR]

A pro-inflammatory cytokine, interleukin 18 (IL-18), induces intracellular expression of IL-1 and the release of IL-6. IL-1 and IL-6 has been detected in anterior pituitary cells, suggesting that IL-18 is produced in anterior pituitary cells and may serve to aid immuno-endocrine regulation. In the present study, we addressed this hypothesis by investigating the intracellular localization of IL-18 and its receptor in bovine anterior pituitary gland. IL-18 mRNA and its protein were detected in the anterior pituitary gland by RT-PCR and Western blotting. In situ hybridization showed that IL-18 mRNA was expressed in the anterior pituitary cells. Immunohistochemistry of IL-18 and specific hormones revealed the presence of IL-18 in somatotrophs. Furthermore, the expression of GH mRNA in IL-18 immunoreactive cells was confirmed by immuno-laser microdissection. These results first demonstrated that somatotrophs produced IL-18. Subsequently, the distribution of the IL-18 receptor alpha (IL-18Rα) was investigated in order to understand IL-18 signaling among the anterior pituitary cells. Bovine IL-18Rα cDNA was partially sequenced and detected in the anterior pituitary gland by RT-PCR. Immunohistochemistry of IL-18Rα, IL-18 and GH showed that IL-18Rα was co-localized in IL-18 immunoreactive cells or somatotrophs. These data suggest that IL-18 acts on somatotrophs as an immuno-endocrine mediator through the autocrine pathway. [ABSTRACT FROM AUTHOR]