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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2016

Abstract

The apple fruit moth (Argyresthia conjugella (A. conjugella)) in Norway was first identified as a pest in apple production in 1899. We here report the first genetic analysis of A. conjugella using molecular markers. Amplified fragment length polymorphism (AFLP) analysis was applied to 95 individuals from six different locations in the two most important apple-growing regions of Norway. Five AFLP primer combinations gave 410 clear polymorphic bands that distinguished all the individuals. Further genetic analysis using the Dice coefficient, Principal Coordinate analysis (PCO) and Bayesian analyses suggested clustering of the individuals into two main groups showing substantial genetic distance. Analysis of molecular variance (AMOVA) revealed greater variation among populations (77.94%) than within populations (22.06%) and significant and high FST values were determined between the two major regions (Distance = 230 km, FST = 0.780). AFLP analysis revealed low to moderate genetic diversity in our population sample from Norway (Average: 0.31 expected heterozygosity). The positive significant correlation between the geographic and the molecular data (r2 = 0.6700) indicate that genetic differences between the two major regions may be due to geographical barriers such as high mountain plateaus (Hardangervidda) in addition to isolation by distance (IBD).

2015

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Abstract

The autumnal moth (Epirrita autumnata) is a cyclically outbreaking forest Lepidoptera with circumpolar distribution and substantial impact on Northern ecosystems. We have isolated 21 microsatellites from the species to facilitate population genetic studies of population cycles, outbreaks, and crashes. First, PCR primers and PCR conditions were developed to amplify 19 trinucleotide loci and two tetranucleotide loci in six multiplex PCR approaches and then analyzed for species specificity, sensitivity and precision. Twelve of the loci showed simple tandem repeat array structures while nine loci showed imperfect repeat structures, and repeat numbers varied in our material between six and 15. The application in population genetics for all the 21 microsatellites were further validated in 48 autumnal moths sampled from Northern Norway, and allelic variation was detected in 19 loci. The detected numbers of alleles per locus ranged from two to 13, and the observed and expected heterozygosities varied from 0.04 to 0.69 and 0.04 to 0.79, respectively. Evidence for linkage disequilibrium was found for six loci as well as indication of one null allele. We find that these novel microsatellites and their multiplex-PCR assays are suitable for further research on fine- and large-scale population-genetic studies of Epirrita autumnata. tri- and tetranucleotide microsatellites; multiplex PCR; Lepidoptera; population genetics

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Abstract

The trans-border brown bear population of Pasvik-Inari-Pechenga (Norway-Finland-Russia) has been monitored using genetic analyses of feces collection since 2005. In addition, in 2007 and 2011, hair traps were systematically placed out in the area to collect hairs for genetic analysis, to more precisely determine the minimum numbers of bears in the area. In 2015, we repeated this hair trap study, using the exact same methodology as in 2007 and 2011, to make a direct comparison of the results from all the 3 study years. Brown bear DNA was detected in 158 of 209 hair samples (76%) obtained from hair traps in 2015 and for 136 of these samples, a complete DNA profile could be determined. We identified 26 different bears in 2015, 17 females and 9 males. We detected 16 bears in Norway, 5 bears in Finland and 9 bears in Russia. Thirteen of these 26 bears were previously unknown, 7 were detected in Norway, 2 in Finland and 4 in Russia. A comparison to the results from 2007 and 2011 showed that we detected more bears in hair traps in 2015 (26 bears) than in 2007 (24 bears) and 2011 (20 bears). We observed an increase in the total yield of hair samples in the traps in 2015 (209 samples) compared to 2007 (196 samples) and 2011 (88 samples). Four (16%) and seven (35%) of the bears caught in hair traps in 2007 and in 2011, respectively, were also recaptured in 2015. Additional samples (scats and hair) collected opportunistically in the field within the Russian and Finnish parts of the study area in 2015 detected 4 male bears and 1 female bear in the Russian part leading to a total of 14 bears identified in Russia, of which 8 bears were detected for the first time. Additional scat and hair samples from the field in Norway were not included in our study and comparisons between the systematic hair-trapping and opportunistic sampling in the field were not performed. However, the results indicate that both methods combined are currently the optimal approach to monitor brown bear numbers in an area.

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Abstract

High-resolution Y-chromosomal markers have been applied to humans and other primates to study population genetics, migration, social structures and reproduction. Y-linked markers allow the direct assessment of the genetic structure and gene flow of uniquely male inherited lineages and may also be useful for wildlife conservation and forensics, but have so far been available only for few wild species. Thus, we have developed two multiplex PCR reactions encompassing nine Y-STR markers identified from the brown bear (Ursus arctos) and tested them on hair, fecal and tissue samples. The multiplex PCR approach was optimized and analyzed for species specificity, sensitivity and stutter- peak ratios. The nine Y-STRs also showed specific STR-fragments for male black bears and male polar bears, while none of the nine markers produced any PCR products when using DNA from female bears or males from 12 other mammals. The multiplex PCR approach in two PCR reactions could be amplified with as low as 0.2 ng template input. Precision was high in DNA templates from hairs, fecal scats and tissues, with standard deviations less than 0.14 and median stutter ratios from 0.04 to 0.63. Among the eight di- and one tetra-nucleotide repeat markers, we detected simple repeat structures in seven of the nine markers with 9–25 repeat units. Allelic variation was found for eight of the nine Y-STRs, with 2–9 alleles for each marker and a total of 36 alleles among 453 male brown bears sampled mainly from Northern Europe. We conclude that the multiplex PCR approach with these nine Y-STRs would provide male bear Y-chromosomal specificity and evidence suited for samples from conservation and wildlife forensics.