bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of microarray‐based diagnostics of voles and shrews for use in biodiversity monitoring studies, and evaluation of mitochondrial cytochrome oxidase I vs. cytochrome b as genetic markers
Authors: Pfunder M. , Holzgang O. , Frey J. E. 
Published: April 2004

AbstractMolecular methods are widely used for species identification of mammals. In particular, the mitochondrial cytochrome b gene sequence has proven helpful for this purpose. Microarray technology can now open up new perspectives for biodiversity monitoring. With microarrays, many thousands of genetically based characteristics can be tested on one microscopic glass slide called a ‘chip’. A ‘Mammalia‐Chip’, for example, could include redundant diagnostic markers to unambiguously identify all European mammal species. Of broader use, and therefore economically more relevant, could be a ‘Biodiversity‐Chip’, containing diagnostic features to distinguish key species in the taxa of bacteria, lichen, molluscs, insects, fungi, mammals, etc. An important prerequisite for any mixed‐phyla chip is a standardization of methods. One of the most promising genes as a universal marker for all eukaryotes is cytochrome oxidase I. We show that cytochrome oxidase I is adequate for the discrimination of different species of voles and shrews with cluster analysis. Based on these results we present a diagnostic microarray‐chip using cytochrome oxidase I sequences for the identification of three species of Sorex (Soricidae, Insectivora) and four species of Microtus (Arvicolinae, Rodentia). We conclude that cytochrome oxidase I can be used as an alternative marker to cytochrome b in a mixed‐phyla chip, or both genes can be used in combination to enhance redundance and thus robustness of a specific chip including small mammals.
Long‐distance pollen flow and tolerance to selfing in a neotropical tree species
Authors: Latouche‐Hallé C. , Ramboer A. , Bandou E. , Caron H. , Kremer A. 
Published: April 2004

AbstractOutcrossing rates, pollen dispersal and male mating success were assessed in Dicorynia guianensis Amshoff, a neotropical tree endemic to the Guiana shield. All adult trees within a continuous area of 40 ha (n = 157) were mapped, and were genotyped with six microsatellite loci. In addition, progenies were genotyped from 22 mature trees. At the population level, the species was mostly outcrossing (tm = 0.89) but there was marked variation among individuals. One tree exhibited mixed mating, confirming earlier results obtained with isozymes that D. guianensis can tolerate selfing. A Bayesian extension of the fractional paternity method was used for paternity analysis, and was compared with the neighbourhood method used widely for forest trees. Both methods indicated that pollen dispersal was only weakly related to distance between trees within the study area, and that the majority (62%) of pollen came from outside the study stand. Using maximum likelihood, male potential population size was estimated to be 1119, corresponding to a neighbourhood size of 560 hectares. Male mating success was, however, related to the diameter of the stem and to flowering intensity assessed visually. The mating behaviour of D. guianensis is a combination of long‐distance pollen flow and occasional selfing. The species can still reproduce when it is extremely rare, either by selfing or by dispersing pollen at long distances. These results, together with the observation that male mating success was correlated with the size of the trees, could be implemented in management procedures aiming at regenerating the species.
Individual assignment test reveals differential restriction to dispersal between two salmonids despite no increase of genetic differences with distance
Authors: Castric Vincent , Bernatchez Louis 
Published: April 2004

AbstractIn many species genes move over limited distances, such that genetic differences among populations or individuals are expected to increase as a function of geographical distance. In other species, however, genes may move any distance over a single generation time, such that no increase of genetic differences is expected to occur with distance. Patterns of gene dispersal have been assessed typically using this theoretical property. In this study, this classical approach based on a Mantel test was compared to a new method using individual assignment to reveal contrasts in dispersal patterns between 15 populations of brook charrSalvelinus fontinalisand 10 populations of Atlantic salmonSalmo salarsampled in eastern Canada, where both species co‐occur naturally. Based on the Mantel test, we found evidence for neither an increase of genetic differences with distance in either species nor a significant contrast between them. The individual‐based method, in contrast, revealed that individual assignment in both species was non random, being significantly biased toward geographically proximate locations. Furthermore, brook charr were on average assigned to a closer river than were salmon, according to a priori expectations based on the dispersal behaviour of the two species. We thus propose that individual assignment methods might be a promising and more powerful alternative to Mantel tests when isolation by distance cannot be postulated a priori.
Speciation, phylogeography and evolution of life history and morphology in plethodontid salamanders of the Eurycea multiplicata complex
Authors: Bonett R. M. , Chippindale P. T. 
Published: April 2004

AbstractUnderstanding the complex interactions among environment, genotype and ontogeny in determining organismal phenotypes is cental to many biological disciplines. The Eurycea multiplicata complex, endemic to the Interior Highlands (Ozark Plateau and Ouachita Mountains) of eastern North America, comprises a diverse radiation of paedomorphic surface‐dwelling (E. tynerensis), metamorphic surface‐dwelling (E. multiplicata multiplicata and E. m. griseogaster) and metamorphic subterranean (Typhlotriton spelaeus) hemidactyliine plethodontid salamanders. Portions of two mitochondrial genes, cytochrome‐b and NADH dehydrogenase‐4, totalling 1818 base pairs (bp) were sequenced for 70 ingroup individuals plus numerous outgroup taxa, to examine the biogeography and relationships among these morphologically disparate species. Results show the E. multiplicata complex to be monophyletic, with its two most divergent clades corresponding to geography, not morphology or life history. Transforming surface‐dwelling populations from the Ouachitas (E. m. multiplicata) are sister to the Ozark taxa, including paedomorphic surface‐dwelling (E. tynerensis), subterranean (T. spelaeus) and transforming surface‐dwelling salamanders assigned to the ‘subspecies’E. m. griseogaster. Among Ozark taxa T. spelaeus (deeply nested within Eurycea) is sister to a clade that includes E. m. griseogaster and E. tynerensis. Current taxonomy suggests that paedomorphic populations (E. tynerensis) from the western Ozarks are distinct from nearby transforming populations (E. m. griseogaster). However, paedomorphic and transforming salamanders do not form reciprocally monophyletic groups and many populations share almost identical haplotypes. Ancestral state reconstruction of life history traits shows that paedomorphosis arose independently from three to nine times. Most populations are either completely paedomorphic or completely transforming. This suggests that local habitat parameters strongly influence life history mode in this complex, either facultatively or by selection for particular genotypes.
Molecular insight into patterns of colony composition and paternity in the common mole‐ratCryptomys hottentotus hottentotus
Authors: Bishop J. M. , Jarvis J. U. M. , Spinks A. C. , Bennett N. C. , O'Ryan C. 
Published: April 2004

AbstractWe report the discovery of intraspecific variation in both colony composition and patterns of paternity in two populations of the social common mole‐ratCryptomys hottentotus hottentotus. These two populations represent the mesic and arid habitat extremes of the species’ broad ecological range in South Africa. Until recently colonies of the common mole‐rat were thought to consist of familial groups whereby all colony members were the offspring of a monogamous reproductive pair. The remaining colony members were thought to forego reproduction until both social and ecological conditions favoured dispersal and opportunities for independent outbreeding. Results from genetic assignment tests using microsatellite markers indicate that while colony composition is dominated by familial groups, colonies within both populations included both adult and subadult foreign conspecifics. Analysis of parentage reveals that the social organization ofC. h. hottentotusis not that of strict monogamy; paternity of offspring was not assigned consistently to the largest, most dominant male within the colony. Moreover, a number of significantly smaller males were found to sire offspring, suggesting a sneak‐mating strategy by subordinate within‐colony males. Extra‐colony extra‐pair paternity (ECP) was also found to characterizeC. h. hottentotuscolonies, occurring with similar frequencies in both habitats. Both dominant established breeding males and subordinate males were identified as siring young in nonsource colonies. Furthermore, established breeding males were found to sire extra‐colony young in the same season as siring young within their source colonies. We discuss the significance of these results within the context of the divergent ecological regimes characterizing the two sites and observe that our results revisit the accuracy of using behavioural and morphological characters, which have structured the basis of our understanding of the behavioural ecology of this species, as indicators of breeding status in mark–recapture studies.
Genetic differentiation and local adaptation in the salt‐marsh beetle Pogonus chalceus: a comparison between allozyme and microsatellite loci
Authors: Dhuyvetter H. , Gaublomme E. , Desender K. 
Published: April 2004

AbstractThe genetic structure of Pogonus chalceus from 11 Atlantic and seven Mediterranean Western European populations was analysed. Results from seven allozyme loci were compared to five microsatellites to test the hypothesis that some enzymatic loci undergo selection. Both allozyme and microsatellite results showed that Mediterranean beetle populations are genetically distinct from Atlantic populations. The analysis of the genetic structure showed that FST values derived from all microsatellite loci were much smaller than those obtained from allozymes. The enzymatic locus Idh‐1 exhibited a high value compared to the other loci, suggesting that it is non‐neutral. The same Idh‐1 locus was implicated in differentiation between temporary and stable populations, as followed also from a highly significant relationship between the allele two of this Idh‐1 locus and dispersal power population estimates. The ‘parallel evolution’ model may account for the diversification of locally adapted Pogonus chalceus populations between different microhabitats.
An ancient bottleneck in the Lost Pines of central Texas
Authors: Al‐Rabab’ah Mohammad A. , Williams Claire G. 
Published: April 2004

AbstractThe retreating edge hypothesis for species responding to climate change predicts severe bottlenecks and eventual extinction. The disjunct Lost Pines population at the westernmost edge of the widespread Pinus taeda range is well suited for testing this prediction. The occurrence of one or more genetic bottlenecks in the Lost Pines population was tested using 34 nuclear microsatellite markers and a control sample from the larger, more continuous east Texas P. taeda forests. The Lost Pines population has undergone drastic contractions in effective population size between 3000 and 30 000 years bp. These results were supported by: (i) detection of transient heterozygosity excess, (ii) a mode‐shift indicator of allele frequencies, and (iii) a ratio of allele number to allele size range. No bottleneck was detected for the east Texas control using any of the three methods. The distribution of allele frequencies was skewed for the Lost Pines population compared to the control, indicating a loss of rare alleles. However, allelic diversity was similar between the Lost Pines population and its east Texas control; the mean allele number per locus was 5.29 and 5.38, respectively. It is proposed that the Lost Pines population was the western refugium for P. taeda during Pleistocene glaciation and that East Texas P. taeda forests descended from the bottlenecked Lost Pines population.
Genetic diversity and divergence among freshwater mussel (Anodonta) populations in the Bonneville Basin of Utah
Authors: Mock K. E. , Brim‐Box J. C. , Miller M. P. , Downing M. E. , Hoeh W. R. 
Published: April 2004

AbstractPopulations of the freshwater mussel genus Anodonta appear to be in a state of rapid decline in western North America, following a trend that unfortunately seems to be prevalent among these animals (Mollusca: Unionoida). Here we describe the patterns of molecular divergence and diversity among Anodonta populations in the Bonneville Basin, a large sub‐basin of the Great Basin in western North America. Using amplified fragment length polymorphism (AFLP) analysis, we found a striking lack of nuclear diversity within some of these populations, along with a high degree of structuring among populations (FST = 0.61), suggesting post‐Pleistocene isolation, due either to a long‐term loss of hydrologic connectivity among populations or to more recent fish introductions. We also found evidence of recent hybridization in one of these populations, possibly mediated by fish‐stocking practices. Using mitochondrial sequence data, we compared the Bonneville Basin populations to Anodonta in several other drainages in western North America. We found a general lack of resolution in these phylogenetic reconstructions, although there was a tendency for the Bonneville Basin Anodonta (tentatively A. californiensis) to cluster with A. oregonensis from the adjacent Lahontan Basin in Nevada. We recommend further investigation of anthropogenic factors that may be contributing to the decline of western Anodonta and a broad‐scale analysis and synthesis of genetic and morphological variation among Anodonta in western North America.
Mectizan Donation Program: evaluation of a public–private partnership
Authors: Peters David H. , Phillips Traci 
Published: April 2004

SummaryThe Mectizan Donation Program (MDP) has been perceived as a highly effective public health programme, and as a possible model for addressing future problems in international health. This evaluation examines how the MDP partnership has been functioning from the perspectives of partner organizations. The results of a survey of 25 partners show that the perceived benefits far outweigh the problems, and that the direct costs to the organizations have been minimal. The partnership is rated highly on many aspects of governance and management, with relatively few problems identified. A factor analysis demonstrated that a wide range of factors have influenced the partners’ perceptions. The benefits with the largest weights appear to be those related to external perceptions of the organization, and those indicating that the organization feels that its opinions will matter and lead to action in the partnership. The biggest factors influencing the positive perceptions on the governance and management of the MDP partnership appear to be the involvement of senior leaders from different organizations, and being able to agree on priorities. The MDP has been able to involve a large and heterogeneous number of partner organizations through relatively informal mechanisms that rely on goodwill and reciprocity. The survey results show how there was a strong alignment of the MDP with the interests of the various partners, and that a manageable number of problems were addressed and services provided. While having long‐term goals, the MDP and the onchocerciasis control programmes have been effective at demonstrating the effectiveness of the approach through regular, professional, and outcome‐oriented evaluations. Although the MDP is considered to be central to concerns of national officials, this feature is not rated as high as public perceptions, the internal characteristics of the partnership, or its accomplishments. Similarly, the need to secure resources is not viewed as a major determinant of the partnership's success, perhaps because resources were readily available through Merck and the partner organizations and programmes. These findings, along with the strategic and operational success of the MDP confirm the view that this type of public–private partnership should be pursued vigorously in other areas of public health. Other potential partnerships would do well to examine the characteristics of the MDP partnership, with careful attention to the features of its governance and the management, including a strong alignment of interests with partners, balancing a long‐term vision with clarity of roles and intensive management of coordination, and professional and results‐oriented accountability.
Economic evaluation of Mectizan distribution
Authors: Waters H. R. , Rehwinkel J. A. , Burnham G. 
Published: April 2004

SummaryThe distribution of ivermectin has dramatically altered the nature of onchocerciasis control. Existing economic analyses of ivermectin distribution programmes show that these programmes have a highly beneficial impact. Most analyses have estimated the economic benefits in terms of increased labour productivity as a result of reductions in blindness, and in terms of additional land‐availability because of a reduced transmission of the parasite. Economic evaluations of the Onchocerciasis Control Program (OPC) in West Africa have calculated a net present value – equivalent discounted benefits minus discounted costs – of $485 million for the programme over a 39‐year period, using a conservative 10% rate to discount future health and productivity gains. The net present value for the African Program for Onchocerciasis Control (APOC) is calculated at $88 million over a 21‐year time period, also using a 10% discount rate. Cost‐effectiveness analyses of ivermectin distribution have found a cost of $14–$30 per disability‐adjusted life‐year prevented – estimates comparable with other priority disease control programmes. However, the economic success of ivermectin distribution is sensitive to the fact that the drug itself has been donated free of charge. The market value of Merck's donations to the APOC for just 1 year considerably outweighs the benefits calculated for both the OPC and the APOC over the life of these projects. Pending the development of an effective macrofilaricide, the distribution of ivermectin will remain a public health priority into the foreseeable future.
Review: The delivery of ivermectin (Mectizan®)
Authors: Burnham G. , Mebrahtu T. 
Published: April 2004

SummaryOver a comparatively short period of time, the development and distribution of ivermectin (Mectizan®) has radically altered the consequences of infection with Onchocerca volvulus. To achieve this required the fostering of many partnerships and the development of new tools and methods. The long‐term commitment of Merck, the World Bank and other sponsors, as well as governments and non‐governmental organizations, has been crucial. Yet the enthusiasm with which communities have taken up the delivery of ivermectin among themselves is perhaps the greatest reason for the success of this programme. The present challenge is sustaining the methods that have brought success so far, and making them part of health services and disease control programmes in some of the world's most impoverished and unstable areas. A major part of this challenge is continuing the commitment to controlling onchocerciasis as memory of the disease is fading, and while the hope of elimination or eradication for most endemic countries remains distant.
Impact of ivermectin on illness and disability associated with onchocerciasis
Authors: Tielsch James M. , Beeche Arlyne 
Published: April 2004

SummaryThe Onchocerciasis Control Program (OCP), one of the most successful vertical disease control programs in the history of public health, came to an end in 2003 with devolvement of responsibilities for control program activities passed to the countries affected. Fortunately, 15 years ago the Mectizan® Distribution Program (MDP) was founded to provide a complementary approach to controlling the disabling consequences of this parasitic infection. With over 250 million doses of ivermectin distributed over the past 15 years, the MDP is well on its way to both solidifying the progress made by the OCP and extending program reach well beyond the boundaries of the OCP. Through the extensive clinical testing protocols implemented in a variety of countries in Aftica, ivermectin has been proven to be a safe and highly effective treatment for onchocerciasis. Regular distribution to populations living in endemic areas has demonstrated significant reductions in blinding ocular complications, transmission, and disability caused by onchocercal skin disease. As yet undocumented, are the likely significant impact regular population dosing with ivermectin has on intestinal helminth infections, lymphatic filariasis, and human scabies infection. While there are significant barriers to continued program success, focussed attention on expanding and improving community‐directed ivermectin distribution is likely to lead to further progress against this resilient infection.
Hookworm (Necator americanus) transmission in inland areas of sandy soils in KwaZulu‐Natal, South Africa
Authors: Mabaso M. L. H. , Appleton C. C. , Hughes J. C. , Gouws E. 
Published: April 2004

SummaryThis study extended the association between hookworm transmission in KwaZulu‐Natal and the sandy coastal plain by investigating the parasite's occurrence in isolated areas of sandy soils further inland. A school‐based prevalence survey was carried out in selected inland sandy areas and in surrounding areas dominated by clay soils within a narrow altitudinal range of between 500 and 700 m to reduce the effect of altitude on climate‐related factors (rainfall and temperature). Sandy areas situated on the coastal plain were included in the analysis for comparative purposes. Soil samples (0–50 mm depth) were collected from each locality to assess their nematode loadings and to analyse selected physical and chemical properties. Significant differences were found between the moderate prevalence of hookworm infection among children living in inland areas with sandy soils (17.3%) and the low prevalence in surrounding non‐sandy areas (5.3%, P < 0.001), and between infection among children living in all inland areas (9.3%) and the high prevalence on the coastal plain (62.5%, P < 0.001). Amounts of fine and medium sand were highest in both the coastal plain soils and in inland sandy areas and these fractions showed a significant positive correlation with hookworm prevalence and nematode loadings. Clay, coarse sand and organic matter contents were highest in surrounding non‐sandy soils and showed a significant negative correlation with the nematode variables. No statistically significant correlations were found with soil pH at study localities. We conclude that properties of inland sandy soils, particularly particle size distribution, correlate well with hookworm prevalence and nematode loadings and therefore provide a more suitable habitat for nematodes than surrounding non‐sandy areas. These results suggest that particle size distribution of sand fractions, organic matter and clay content in the soil influence the survival of hookworm larvae and hence the parasite's transmission.