bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution and status of the polecat Mustela putorius in Luxembourg
Authors: BAGHLI ADIL , VERHAGEN RONALD 
Published: December 2004

ABSTRACT 1. The presence and distribution of the polecat Mustela putorius in Luxembourg was studied for the first time. Postal surveys were conducted among all the tenants of the hunting areas and all the farmers in the country. 2. Except for the otter Lutra lutra, the polecat appears to be the least common mustelid in Luxembourg. Farmers and hunters perceived the polecat differently according to their interests. Farmers had a more tolerant attitude towards the species but 17% still considered it a pest. 3. Live trapping of polecats was carried out for 3 years: 16 individuals were caught. This suggests a very low population density. Hunting records of this mustelid were examined for the period 1955–2000. There has been a very strong decrease in the number of polecats killed, giving rise to concerns that its population may be dramatically declining. Moreover, hunting data from neighbouring Germany confirm that this is a regional situation.
The distribution of mountain haresLepus timidusin Europe: a challenge from brown haresL. europaeus?
Authors: THULIN CARL‐GUSTAF 
Published: December 2004

ABSTRACT1. Throughout the most recent glacial period (Weichsel), the mountain hareLepus timidushad a continuous distribution in the tundra habitat south of the ice‐rim. When the ice retreated, mountain hares colonized deglaciated land, and spread over northern Europe.2. Since the Weichsel, the mountain hare's distribution in Europe has been gradually reduced and at present comprises Ireland and the Scottish Highlands, high altitudes in the Alps, isolated forests in eastern Poland, most of Fennoscandia and from the Baltic countries eastwards through Russia. Declines during the last century have been observed in Sweden and Russia.3. This review defines and evaluates causes for this gradual reduction and fragmentation of the mountain hare's distribution, with special focus on interactions with brown haresLepus europaeus. The relative importance of diseases, predation, cultivation and interactions with other herbivores than brown hares are discussed.4. A plausible cause of the possible permanent disappearance of mountain hares in Europe appears to be exclusion by interspecific competition and hybridization with, and/or epidemic diseases mediated by, the congeneric brown hare.
Diet of wild boar Sus scrofa in Western Europe, with particular reference to consumption of agricultural crops
Authors: SCHLEY LAURENT , ROPER TIMOTHY J. 
Published: December 2004

ABSTRACT 1. The diet of wild boar Sus scrofa in Western Europe is reviewed, paying particular attention to the consumption of agricultural crops and the implications of this from the point of view of crop damage. Data were taken mainly from 11 studies that provide quantitative information about the consumption of different food types, but we also list all the foods reported as being eaten by wild boar in a total of 21 studies. 2. Vegetable foods occurred more frequently in the diet than animal foods, and also constituted the bulk of the food ingested. Overall, there were four major vegetable food categories: mast, roots, green plant matter and agricultural crops. Depending on the study area, wild boar always consumed at least one energy‐rich plant food such as acorns, beechnuts, chestnuts, pine seeds, olives, cereal grains or other crops. The number and types of agricultural crops consumed varied between study areas but crops represent an important component of wild boar diet throughout its Western European range. Among animal foods, insects, earthworms, birds and mammals were eaten most consistently but the diet also included amphibians, reptiles, gastropods and myriapods. 3. Seasonal, interannual and regional differences in the diet, together with its striking overall breadth, indicate that wild boar are opportunistic omnivores whose diet, in any particular instance, is largely determined by the relative availability of different food types. Dependence on energy‐rich plant material as a major component of the diet, coupled with large body size and a propensity to trample crops as well as consume them, means that wild boar cause significant agricultural damage.
Contrasting selection pressures on components of the Ras‐mediated signal transduction pathway in Drosophila
Authors: Riley Rebecca M. , Jin WeI , Gibson Greg 
Published: December 2004

AbstractThe molecular genetics of several signal transduction pathways is well characterized, providing an opportunity to address the nature of the population genetic forces acting on functionally related suites of pleiotropic regulatory genes. Signal transduction is the process by which signals are transmitted from the cell surface to the nucleus or other cellular structures. It plays a fundamental role in regulating a wide range of developmental and physiological processes, many of which are likely to be subject to buffering mechanisms. Here we infer that contrasting selection pressures act on six components of the Ras signal transduction pathway by comparing sequences obtained from 25 alleles of Drosophila melanogaster with one allele of the sibling species D. simulans. The three most upstream components of the cascade, Ras, Drk and polehole, experience strong purifying selection, as they show no fixed amino acid differences between the species and just a handful of rare replacement polymorphisms within D. melanogaster. This portion of the pathway is likely to act as a control point in signal transduction, because the more downstream components Dsor1, corkscrew and Ksr, each show several amino acid replacements between the species. Furthermore, Ksr is nearly monomorphic within D. melanogaster, and application of the HKA and McDonald and Kreitman tests indicate that this gene may have experienced a recent selective sweep, suggesting that modifiers of Ras kinase signalling are the most likely source of quantitative variation associated with this core regulatory pathway.
Effect of heat shock, pretreatment and hsp70 copy number on wing development in Drosophila melanogaster
Authors: Williams Karen D. , Helin Amanda B. , Posluszny Joseph , Roberts Stephen P. , Feder Martin E. 
Published: December 2004

AbstractNaturally occurring heat shock (HS) during pupation induces abnormal wing development in Drosophila; we examined factors affecting the severity of this induction. The proportion of HS‐surviving adults with abnormal wings varied with HS duration and intensity, and with the pupal age or stage at HS administration. Pretreatment (PT), mild hyperthermia delivered before HS, usually protected development against HS. Gradual heating resembling natural thermal regimes also protected wing development against thermal disruption. Because of the roles of the wings in flight and courtship and in view of natural thermal regimes that Drosophila experience, both HS‐induction of wing abnormalities and its abatement by PT may have marked effects on Drosophila fitness in nature. Because PT is associated with expression of heat‐inducible molecular chaperones such as Hsp70 in Drosophila, we compared thermal disruption of wing development among hsp70 mutants as well as among strains naturally varying in Hsp70 levels. Contrary to expectations, lines or strains with increased Hsp70 levels were no more resistant to HS‐disruption of wing development than counterparts with lower Hsp70 levels. In fact, wing development was more resistant to HS in hsp70 deletion strains than control strains. We suggest that, while high Hsp70 levels may aid cells in surviving hyperthermia, high levels may also overly stimulate or inhibit numerous signalling pathways involved in cell proliferation, maturation and programmed death, resulting in developmental failure.
Nuclear gene sequences and DNA variation of Cryptomeria japonica samples from the postglacial period
Authors: Tani Naoki , Tsumura Yoshihiko , Sato Hitoshi 
Published: December 2004

AbstractGenomic DNA was extracted from heartwood blocks of six Cryptomeria japonica individuals that had been buried (in an area now covered by rice fields) for about 3600 years. Attempts were made to determine the sequences of five nuclear genes following polymerase chain reaction amplification, using previously obtained C. japonica expressed sequence tag (EST) information. We detected 15 nucleotide substitutions and four insertion/deletions (indels) in a partial GapC gene sequence among 13 individuals of the buried and an extant population, which allowed us to estimate the extent of DNA variation within the buried populations, and the level of genetic differentiation between the buried population and the extant population growing in a neighbouring area. For the entire haplotypes of the GapC region, π and θ nucleotide diversity estimates were 0.0063 and 0.0010, respectively, when both populations were included, while corresponding figures for the buried population alone were 0.0009 and 0.0017. Estimates of DNA divergence statistics (dXY = 0.0062, dA = 0.0005, FST = 0.0832 and KST = 0.0935) suggest that differentiation between the two populations was not great. However, permutation tests gave FST and KST values rejecting the null hypothesis (that populations were not differentiated) at the 5% and 1% probability levels, respectively. The significant genetic differentiation between the two populations was mainly caused by differences in haplotype diversity. The significant level of haplotype diversity in the extant population compared to the buried population might be the result of gene flow from neighbouring artificial forests. Alternatively, it is possible that we failed to detect all the DNA variation in the buried population because of clonal growth in the buried population.
Side‐stepping secondary symbionts: widespread horizontal transfer across and beyond the Aphidoidea
Authors: Russell J. A. , Latorre A. , Sabater‐Muñoz B. , Moya A. , Moran N. A. 
Published: December 2004

AbstractTo elucidate the co‐evolutionary relationships between phloem‐feeding insects and their secondary, or facultative, bacterial symbionts, we explore the distributions of three such microbes — provisionally named the R‐type (or PASS, or S‐sym), T‐type (or PABS), and U‐type — across a number of aphid and psyllid hosts through the use of diagnostic molecular screening techniques and DNA sequencing. Although typically maternally transmitted, phylogenetic and pairwise divergence analyses reveal that these bacteria have been independently acquired by a variety of unrelated insect hosts, indicating that horizontal transfer has helped to shape their distributions. Based on the high genetic similarity between symbionts in different hosts, we argue that transfer events have occurred recently on an evolutionary timescale. In several instances, however, closely related symbionts associate with related hosts, suggesting that horizontal transfer between distant relatives may be rarer than transmission between close relatives. Our findings on the prevalence of these symbionts within many aphid taxa, along with published observations concerning their effects on host fitness, imply a significant role of facultative symbiosis in aphid ecology and evolution.
Analysis of a chalcone synthase mutant in Ipomoea purpurea reveals a novel function for flavonoids: amelioration of heat stress
Authors: Coberly L. C. , Rausher M. D. 
Published: December 2004

AbstractFlavonoids are thought to function in the plant stress response and male fertility in some, but not all, species. We examined the effects of a self‐fertile chalcone synthase null allele, a, for the effects of heat and light stress on fertilization success and flower production in Ipomoea purpurea. Pollen recipients and pollen donors of both homozygous genotypes exhibit reduced fertilization success at high temperatures, indicating that high temperature acts as a stress‐lowering fertilization success. Homozygous aa individuals exhibit reduced male and female fertilization success, compared to AA individuals, at high temperatures but not at low temperatures. In addition, aa individuals produce fewer flowers than AA individuals at low temperatures, but not at high temperatures. These results suggest that flavonoids alleviate heat stress on fertilization success. They also suggest that pleiotropic effects at the A locus may explain the low frequency of the a allele in natural populations.
Different genes underlie adaptive melanism in different populations of rock pocket mice
Authors: Hoekstra H. E. , Nachman M. W. 
Published: December 2004

AbstractIdentifying the genes responsible for adaptation has been an elusive goal in evolutionary biology. Rock pocket mice (Chaetodipus intermedius) provide a useful system for studying the genetics of adaptation: mostC. intermediusare light‐coloured and live on light‐coloured rocks, but in several different geographical regions,C. intermediusare melanic and live on dark‐coloured basalt lava, presumably as an adaptation for crypsis. Previous work demonstrated that mutations at the melanocortin‐1 receptor gene (Mc1r) are responsible for the dark/light difference in mice from one population in Arizona. Here, we investigate whether melanism has evolved independently in populations of darkC. intermediusfrom New Mexico, and whether the same or different genes underlie the dark phenotype in mice from these populations compared with the dark mice from Arizona. Seventy‐six mice were collected from pairs of dark and light localities representing four different lava flows and adjacent light‐coloured rocks; lava flows were separated by 70–750 km. Spectrophotometric analysis of mouse pelage and of rock samples revealed a strong positive association between coat colour and substrate colour. No significant differences were observed in the colour of rocks among the four lava flows, suggesting that mice in these separate populations have experienced similar selection for crypsis. Despite this similarity in environment, melanic mice from the three New Mexico populations were slightly, but significantly, darker than melanic mice from Arizona. The entireMc1rgene was sequenced in all mice. The previously identified mutations responsible for the light/dark difference in mice from Arizona were absent in all melanic mice from three different populations in New Mexico. Five newMc1rpolymorphisms were observed among mice from New Mexico, but none showed any association with coat colour. These results indicate that adaptive melanism has arisen at least twice inC. intermediusand that these similar phenotypic changes have a different genetic basis.
Prospects for inferring pairwise relationships with single nucleotide polymorphisms
Authors: Glaubitz Jeffrey C. , Rhodes O. Eugene , Dewoody J. Andrew 
Published: December 2004

AbstractAn extraordinarily large number of single nucleotide polymorphisms (SNPs) are now available in humans as well as in other model organisms. Technological advancements may soon make it feasible to assay hundreds of SNPs in virtually any organism of interest. One potential application of SNPs is the determination of pairwise genetic relationships in populations without known pedigrees. Although microsatellites are currently the marker of choice for this purpose, the number of independently segregating microsatellite markers that can be feasibly assayed is limited. Thus, it can be difficult to distinguish reliably some classes of relationship (e.g. full‐sibs from half‐sibs) with microsatellite data alone. We assess, via Monte Carlo computer simulation, the potential for using a large panel of independently segregating SNPs to infer genetic relationships, following the analytical approach of Blouin et al. (1996). We have explored a ‘best case scenario’ in which 100 independently segregating SNPs are available. For discrimination among single‐generation relationships or for the identification of parent–offspring pairs, it appears that such a panel of moderately polymorphic SNPs (minor allele frequency of 0.20) will provide discrimination power equivalent to only 16–20 independently segregating microsatellites. Although newly available analytical methods that can account for tight genetic linkage between markers will, in theory, allow improved estimation of relationships using thousands of SNPs in highly dense genomic scans, in practice such studies will only be feasible in a handful of model organisms. Given the comparable amount of effort required for the development of both types of markers, it seems that microsatellites will remain the marker of choice for relationship estimation in nonmodel organisms, at least for the foreseeable future.
Clonal diversity and genetic differentiation in Ilex leucoclada M. patches in an old‐growth beech forest
Authors: Torimaru T. , Tomaru N. , Nishimura N. , Yamamoto S. 
Published: December 2004

AbstractWe investigated clonal diversity within patches of Ilex leucoclada and genetic variation within and among patches using random amplified polymorphic DNA (RAPD) markers in a 1‐ha plot within an old‐growth beech forest. We found 38 patches that exhibited a clumped distribution in the middle of the plot. We identified a total of 166 RAPD phenotypes among the 215 stems sampled from 27 patches that were completely within the plot. The population showed high clonal diversity within patches (mean number of genets relative to number of stems = 0.79; mean Simpson's D= 0.89). Variation in RAPD phenotypes among patches was highly significant (ΦST in the molecular variance analysis = 0.316, P < 0.001), indicating genetic differentiation among patches. Pairwise genetic distances, ΦST, among patches did not correlate with geographical distances among patches. The cluster analysis based on the genetic distances showed few clear clusters of patches, indicating no spatial genetic structure among patches. High levels of clonal diversity both within patches and within the population may be explained by multiple founders, seedling recruitment during patch‐formation, and somatic mutation. The significant genetic differentiation among patches may be caused by separate founding events and/or kin structuring within patches.
Effects of transgenic Bt corn litter on the earthwormLumbricus terrestris
Authors: Zwahlen C. , Hilbeck A. , Howald R. , Nentwig W. 
Published: December 2004

AbstractA 200‐day study was carried out to investigate the impact of transgenicBacillus thuringiensis(Bt) corn on immature and adultLumbricus terrestrisin the field and in the laboratory. Another objective of this study was to develop test methods that could be used for standard testing of the impact of transgenic plants on different earthworm species in the field and in the laboratory. For this purpose two different experiments were involved, a laboratory experiment with adultL. terrestrisand a field experiment with immatureL. terrestris. No lethal effects of transgenic Bt corn on immature and adult earthworms were observed. ImmatureL. terrestrisin the field had a very similar growth pattern when fed either (Bt+) or (Bt−) corn litter. No significant differences in relative weights of (Bt+) and (Bt−) corn‐fed adultL. terrestriswere observed during the first 160 days of the laboratory trial, but after 200 days adultL. terrestrishad a significant weight loss of 18% of their initial weight when fed (Bt+) corn litter compared to a weight gain of 4% of the initial weight of (Bt−) corn‐fed earthworms. Further studies are necessary to see whether or not this difference in relative weight was due to the Bt toxin or other factors discussed in the study. Degradation of Cry1Ab toxin in corn residues was significantly slower in the field than at 10 °C in the laboratory. Enzyme‐linked immunosorbent assay results indicated that earthworms in both experiments were exposed to the Bt toxin throughout the whole experimental time.
Natural selection for salt tolerance quantitative trait loci (QTLs) in wild sunflower hybrids: Implications for the origin ofHelianthus paradoxus, a diploid hybrid species
Authors: Lexer C. , Welch M. E. , Durphy J. L. , Rieseberg L. H. 
Published: December 2004

AbstractFor a new diploid or homoploid hybrid species to become established, it must diverge ecologically from parental genotypes. Otherwise the hybrid neospecies will be overcome by gene flow or competition. We initiated a series of experiments designed to understand how the homoploid hybrid species,Helianthus paradoxus, was able to colonize salt marsh habitats, when both of its parental species (H. annuus×H. petiolaris) are salt sensitive. Here, we report on the results of a quantitative trait locus (QTL) analysis of mineral ion uptake traits and survivorship in 172 BC2hybrids betweenH. annuusandH. petiolaristhat were planted inH. paradoxussalt marsh habitat in New Mexico. A total of 14 QTLs were detected for mineral ion uptake traits and three for survivorship. Several mineral ion QTLs mapped to the same position as the survivorship QTLs, confirming previous studies, which indicated that salt tolerance inHelianthusis achieved through increased Ca uptake, coupled with greater exclusion of Na and related mineral ions. Of greater general significance was the observation that QTLs with effects in opposing directions were found for survivorship and for all mineral ion uptake traits with more than one detected QTL. This genetic architecture provides an ideal substrate for rapid ecological divergence in hybrid neospecies and offers a simple explanation for the colonization of salt marsh habitats byH. paradoxus. Finally, selection coefficients of +0.126, −0.084 and −0.094 for the three survivorship QTLs, respectively, are sufficiently large to account for establishment of new, homoploid hybrid species.
Adaptation at specific loci. VII. Natural selection, dispersal and the diversity of molecular–functional variation patterns among butterfly species complexes (Colias: Lepidoptera, Pieridae)
Authors: Watt W. B. , Wheat C. W. , Meyer E. H. , Martin J.‐F. 
Published: December 2004

AbstractNatural genetic variants at the phosphoglucose isomerase, PGI, gene differ in spatial patterning of their polymorphism among species complexes ofColiasbutterflies in North America. In both lowland and alpine complexes, molecular–functional properties of the polymorphic genotypes can be used to predict genotype‐specific adult flight performances and resulting large genotypic differences in adult fitness components. In the lowland species complex, there is striking uniformity of PGI polymorph frequencies at a number of sites across the American West; this fits with earlier findings of strong, similar differences in fitness components over this range. In an alpine complex,Colias meadiishows similar uniformity of PGI frequencies within habitat types, either montane steppe or alpine tundra, over several hundred kilometres in the absence of dispersal. At the same time, large shifts (10–20%) in frequency of the most common alleles occur between steppe and tundra populations, whether these are isolated or, as in some cases, are in contact and exchange many dispersing adults each generation. Data on male mating success of commonC. meadiiPGI genotypes in steppe and tundra show heterozygote advantage in both habitat types, with shifts in relative homozygote disadvantage between habitats which are consistent with observed frequency differences. Nonadaptive explanations for this situation are rejected, and alternative, thermal‐ecology‐based adaptive hypotheses are proposed for later experimental test. These findings show that strong local selection may dominate dispersal as an evolutionary agent, whether or not dispersal is present, and that selection may often be the major force promoting ‘cohesion’ of species over long distances. This case offers new opportunities for integrating studies of molecular structure and function with ecological aspects of natural selection in the wild, both within and among species.