Genetic variation and population structure of American mink Neovison vison from PCB-contaminated and non-contaminated locales in eastern North America

Establishment of mink heart identification method based on mitochondrial cytochrome b gene and development of its detection kit

In this study, the mink heart mitochondrial DNA was used as the target gene to design the specific primers of mink heart mtDNA Cytb, the extraction and detection reagents of mink heart DNA were developed using DNA fingerprinting technique, and the specificity, reproducibility, and stability of the reagents were investigated. Molecular cloning and sequencing technique were used to clone the standard substance of mink heart DNA detection, then a DNA fingerprint detection method of mink heart and the quality standard for mink heart were established, and a DNA detection kit of mink heart was developed. The results showed that the structure of DNA extracted from mink heart by self-developed reagents was complete, and both the concentration and purity of DNA were high. A specific amplification band of the original mink samples was found at 337 bp. The sequence of mink heart DNA was consistent with that of mink heart mtDNA specific fingerprint region. The mink heart DNA fingerprint identification method established, in this study, is accurate and reliable, and the procedure of the developed DNA kit is easy, the results obtained using this kit is stable and the method is suitable for popularization and application.

Turning natural adaptations to oncogenic factors into an ally in the war against cancer

Both field and experimental evolution studies have demonstrated that organisms naturally or artificially exposed to environmental oncogenic factors can, sometimes rapidly, evolve specific adaptations to cope with pollutants and their adverse effects on fitness. Although numerous pollutants are mutagenic and carcinogenic, little attention has been given to exploring the extent to which adaptations displayed by organisms living in oncogenic environments could inspire novel cancer treatments, through mimicking the processes allowing these organisms to prevent or limit malignant progression. Building on a substantial knowledge base from the literature, we here present and discuss this progressive and promising research direction, advocating closer collaboration between the fields of medicine, ecology, and evolution in the war against cancer.

Genetic structure of introduced American mink (Neovison vison) in Patagonia: colonisation insights and implications for control and management strategies

Context Biological invasions have caused dramatic changes in native biodiversity and ecosystem function. Studies of genetic variation and evolutionary changes are useful for understanding population dynamics during biological invasions, and shed light on management, prevention and restoration strategies. Aims This study aimed to investigate the structure and genetic variability of American mink (Neovison vison), an invasive species in southern South America, introduced for fur farming in the 1930s. Methods Samples from 153 mink were obtained from 12 locations in southern Chile to sequence the mitochondrial DNA (mtDNA) control region and to genotype 11 polymorphic microsatellite loci. Key results The highest mtDNA diversity was detected in Puerto Cisnes, suggesting multiple introductions and/or the most probable area where mink was first introduced. The latter is also supported by microsatellite data, because a high percentage of individuals from different locations were assigned to this location. All other locations showed low or no mtDNA diversity, possibly due to founder effect. The results also indicate marked population structure, with three genetic clusters coincident with the main historical introduction points, with low dispersal among them. Conclusions The results suggest that control strategies for American mink in southern Chile should be concentrated on these three genetically differentiated management units, and particularly on source populations and locations with low effective population size and restricted connectivity. Implications Genetic approaches have been used for the management of numerous alien species worldwide. Recommendations delivered here for American mink control could also be implemented in other regions and for other invasive species with similar genetic diversity distribution and connectivity.

Evolutionary consequences of historical metal contamination for natural populations of Chironomus riparius (Diptera: Chironomidae)

Populations inhabiting metal-impacted freshwater systems located nearby industrial and urban areas may be under intense selection. The present study aims to address two fundamental microevolutionary aspects of metal contamination in the midge Chironomus riparius (Meigen): Are populations inhabiting historically metal contaminated sites genetically adapted to metals? And, are populations from these sites genetically eroded? To answer these questions, C. riparius populations were sampled from three sites with well-known histories of metal contamination and three nearby-located references. Genetic adaptation to metals was investigated through acute and chronic exposures to cadmium (Cd), after rearing all populations for at least six generations under laboratory clean conditions. Genetic diversity was estimated based on the allelic variation of seven microsatellite markers. Results showed higher acute tolerance to Cd in populations originating from metal contaminated sites compared to their respective references and significant differences in two out of three pairwise comparisons. However, there was a mismatch between acute and chronic tolerance to Cd with results of the partial life-cycle tests suggesting fitness costs under control clean conditions in two metal-adapted populations. Despite no evidences of genetic erosion in populations sampled from metal contaminated sites, our results suggest genetically inherited tolerance to Cd in populations inhabiting historically contaminated sites. These findings lend support to the use of C. riparius as a model organism in evolutionary toxicology and highlight the importance of coupling measures of neutral genetic diversity with assessments of chemical tolerance of populations for a better understanding of contaminant-induced adaptation and evolutionary processes.