bluuebunny/crossref_metadata_2025_split huggingface dataset:
Islands within an island: phylogeography and conservation genetics of the endangered Hawaiian tree snail Achatinella mustelina
Authors: Holland Brenden S. , Hadfield Michael G. 
Published: March 2003

AbstractMitochondrial DNA (mtDNA) sequences were used to evaluate phylogeographic structure within and among populations of three endangered Hawaiian tree snail species (n = 86). The primary focus of this investigation was on setting conservation priorities for Achatinella mustelina. Limited data sets for two additional endangered Hawaiian tree snails, A. livida and A. sowerbyana, were also developed for comparative purposes. Pairwise genetic distance matrices and phylogenetic trees were generated, and an analysis of molecular variance was performed on 675‐base pair cytochrome oxidase I gene sequences from multiple populations of Hawaiian tree snails. Sequence data were analysed under distance‐based maximum‐likelihood, and maximum‐parsimony optimality criteria. Within the focal species, A. mustelina, numbers of variable and parsimony informative sites were 90 and 69, respectively. Pairwise intraspecific mtDNA sequence divergence ranged from 0 to 5.3% in A. mustelina, from 0 to 1.0% in A. livida and from 0 to 1.9% in A. sowerbyana. For A. mustelina, population genetic structure and mountain topography were strongly correlated. Maximum genetic distances were observed across deep, largely deforested valleys, and steep mountain peaks, independent of geographical distance. However, in certain areas where forest cover is presently fragmented, little mtDNA sequence divergence exists despite large geographical scales (8 km). Genetic data were used to define evolutionarily significant units for conservation purposes including decisions regarding placement of predator exclusion fences, captive propagation, re‐introduction and translocation.
Transgenic potatoes with enhanced levels of nematode resistance do not have altered susceptibility to nontarget aphids
Authors: Cowgill S. E. , Wright C. , Atkinson H. J. 
Published: March 2003

AbstractCysteine proteinase inhibitors (cystatins) confer resistance to plant‐parasitic nematodes when expressed in transgenic plants. The survival and growth of nymphs of the peach‐potato aphid, Myzus persicae, were adversely affected when cystatins were added to artificial diets. When aphids were clip‐caged onto transgenic plants expressing chicken egg white cystatin (CEWc) there was no adverse effect on aphid fitness. Field populations of aphids on transgenic Desiree potatoes, expressing CEWc or a modified version of oryzacystatin I, were not significantly different from populations on control Desiree plants. The effect of other nematode management options on aphid numbers was also studied. A conventionally bred cultivar, with partial nematode resistance, supported higher populations of aphids than the transgenic lines at the beginning of the sampling period. Peak aphid densities on the untreated control and untreated transgenic lines were 7 and 5.2 aphids per plant. Aldicarb, commonly used to control nematodes on potatoes, reduced the value to less than 0.2 aphids per plant. The results demonstrate that levels of expression in the plant tissue actually consumed are important in determining the risk of cystatins to nontarget invertebrates. The study also highlights the importance of including currently used management options in any assessment of the impact of transgenic plants on nontarget organisms.
Maternal lineages ofPinus densata, a diploid hybrid
Authors: Song Bao‐Hua , Wang Xiao‐Quan , Wang Xiao‐Ru , Sun Lan‐Ju , Hong De‐Yuan , Peng Pei‐Hao 
Published: March 2003

AbstractPrevious morphological, allozyme and chloroplast DNA data have suggested thatPinus densataoriginated through hybridization betweenP.tabuliformis andP.yunnanensis. In the present study, sequence and restriction site analyses of maternally inherited mitochondrialnad1 intron were used to detect variation patterns in 19 populations ofP.tabuliformis,P.yunnanensisandP.densata. A total of three mitotypes (A, B, C) were detected. All but one of the populations ofP.yunnanensispossessed mitotype B while all populations ofP.tabuliformishad mitotype A.Pinus densatapopulations, on the other hand, harboured both mitotypes A and B, which are characteristic ofP.tabuliformisandP.yunnanensis, respectively.This result gives strong additional evidence supporting the hybrid origin of this diploid pine. The distribution of mitotypes indicated very different mating compositions and evolutionary history amongP.densatapopulations. It seems that local founder populations and backcrosses may have played important roles in the early establishment ofP.densatapopulations. The uplift of the Tibetan Plateau had a significant impact on the distribution of maternal lineages ofP.densatapopulations.
The phylogeography and connectivity of the latitudinally widespread scleractinian coralPlesiastrea versiporain the Western Pacific
Authors: Rodriguez‐Lanetty M. , Hoegh‐Guldberg O. 
Published: March 2003

AbstractWhereas terrestrial animal populations might show genetic connectivity within a continent, marine species, such as hermatypic corals, may have connectivity stretching to all corners of the planet. We quantified the genetic variability within and among populations of the widespread scleractinian coral,Plesiastrea versiporaalong the eastern Australian seaboard (4145 km) and the Ryukyu Archipelago (Japan, 681 km) using sequences of internal transcribed spacers (ITS1‐2) from ribosomal DNA. Geographic patterns in genetic variability were deduced from a nested clade analysis (NCA) performed on a parsimony network haplotype. This analysis allowed the establishment of geographical associations in the distribution of haplotypes within the network cladogram, therefore allowing us to deduce phylogeographical patterns based under models of restricted gene flow, fragmentation and range expansion. No significant structure was found among Ryukyu Archipelago populations. The lack of an association between the positions of haplotypes in the cladogram with geographical location of these populations may be accounted for by a high level of gene flow ofP. versiporawithin this region, probably due to the strong Kuroshio Current. In contrast, strong geographical associations were apparent among populations ofP. versiporaalong the south‐east coast of Australia. This pattern of restricted genetic connectivity among populations ofP. versiporaon the eastern seaboard of Australia seems to be associated with the present surface ocean current (the East Australian Current) on this side of the south‐western Pacific Ocean.
The genetic structure of natural and reintroduced roe deer (Capreolus capreolus) populations in the Alps and central Italy, with reference to the mitochondrial DNA phylogeography of Europe
Authors: Vernesi C. , Pecchioli E. , Caramelli D. , Tiedemann R. , Randi E. , Bertorelle G. 
Published: March 2003

AbstractThe first hypervariable fragment (HVI) of the mitochondrial DNA control region was sequenced in 90 individuals of the European roe deer (Capreolus capreolus) from the Alps, central Italy and Spain. Pooling these data with 70 published sequences from several European regions, we were able to identify patterns of divergence within the Italian peninsula, and in Europe in general. The results we obtained can be summarized as follows. First, the genetic structure of European roe deer populations is substantial (ΦST values around 0.6). Second, the divergence between some central Italian populations, the Alpine group (which is genetically close to the French, the Spanish and the Norwegian samples) and the Eastern European populations seems to reflect Upper Pleistocene subdivisions, possibly related to three southern European refugia. Third, a different group of central Italian individuals probably diverged more recently from the Alpine group, and their attribution to the subspecies C. c. italicus does not appear justified. Fourth, the analysis of mitochondrial DNA in the roe deer can be used to identify recently reintroduced animals in the western Alps which clearly cluster within the Eastern European group, thus providing an important tool for conservation and management strategies for this species.
Applications of selective neutrality tests to molecular ecology
Authors: Ford Michael J. 
Published: March 2003

AbstractThis paper reviews how statistical tests of neutrality have been used to address questions in molecular ecology are reviewed. The work consists of four major parts: a brief review of the current status of the neutral theory; a review of several particularly interesting examples of how statistical tests of neutrality have led to insight into ecological problems; a brief discussion of the pitfalls of assuming a strictly neutral model if it is false; and a discussion of some of the opportunities and problems that molecular ecologists face when using neutrality tests to study natural selection.
Investigation of the population genetic structure and mating system in the antPheidole pallidula
Authors: Fournier Denis , Aron Serge , Milinkovitch Michel C. 
Published: March 2003

AbstractThe origin of eusociality in haplo‐diploid organisms such as Hymenoptera has been mostly explained by kin selection. However, several studies have uncovered decreased relatedness values within colonies, resulting primarily from multiple queen matings (polyandry) and/or from the presence of more than one functional queen (polygyny). Here, we report on the use of microsatellite data for the investigation of sociogenetic parameters, such as relatedness, and levels of polygyny and polyandry, in the antPheidole pallidula. We demonstrate, through analysis of mother–offspring combinations and the use of direct sperm typing, that each queen is inseminated by a single male. The inbreeding coefficient within colonies and the levels of relatedness between the queens and their mate are not significantly different from zero, indicating that matings occur between unrelated individuals. Analyses of worker genotypes demonstrate that 38% of the colonies are polygynous with 2–4 functional queens, and suggest the existence of reproductive skew, i.e. unequal respective contribution of queens to reproduction. Finally, our analyses indicate that colonies are genetically differentiated and form a population exhibiting significant isolation‐by‐distance, suggesting that some colonies originate through budding.
The influence of mating system, demography, parasites and colonization on the population structure ofBiomphalaria pfeifferiin Madagascar
Authors: Charbonnel N. , Angers B. , Rasatavonjizay R. , Bremond P. , Debain C. , Jarne P. 
Published: March 2003

AbstractCurrent evolutionary forces and historical processes interact to shape the distribution of neutral genetic variability within and among populations. Focusing on the genetics of recently introduced organisms offers a good opportunity to understand the relative importance of these factors. This study concerns variation at 8 polymorphic microsatellite loci in 30 populations ofBiomphalaria pfeifferi. The sampling area spans most of the species’ range in Madagascar where it was probably introduced recently. Extremely low variation was found within all populations studied, which may partly result from high selfing rates. However, this cannot account for the variance of variation across populations, which is better explained by habitat openness (that reflects environmental stochasticity), the prevalence of the parasitic trematodeSchistosoma mansoniand historical demography (colonization and subsequent bottlenecks). Large global differentiation was also observed, suggesting that current gene flow among populations is limited to small distances, within watersheds and to few individuals. Our data set also allowed us to test several hypotheses regarding colonization, based on bottleneck and admixture tests. The observed pattern requires at least two independent introductions from slightly differentiated genetic sources in the western part of Madagascar. Another introduction, from a very different genetic origin, should also be postulated to explain the genetic composition of eastern populations. That this introduction occurred recently suggests that the colonization of Madagascar byB. pfeifferiis an ongoing process.
Genetic structure of Anopheles gambiae (Diptera: Culicidae) in São Tomé and Príncipe (West Africa): implications for malaria control
Authors: Pinto J. , Donnelly M. J. , Sousa C. A. , Gil V. , Ferreira C. , Elissa N. , Do Rosário V. E. , Charlwood J. D. 
Published: March 2003

AbstractThe impact of a vector eradication programme, conducted in the 1980s, on Anopheles gambiae populations from the islands of São Tomé and Príncipe, was evaluated by microsatellite DNA analysis. Significant genetic differentiation was observed within and between the two islands and between the islands and a population from Gabon, suggesting a degree of isolation between them. Large estimates of long‐term Ne suggested that the control programme did not affect the effective population size of the vector. Heterozygosity tests were also not consistent with a recent bottleneck.
Glacial‐induced altitudinal migrations inArmeria(Plumbaginaceae) inferred from patterns of chloroplast DNA haplotype sharing
Authors: Gutiérrez Larena B. , Fuertes Aguilar J. , Nieto Feliner G. 
Published: March 2003

AbstractIn contrast to northern European areas where large‐scale migrations occurred to recolonize territories after glacial periods, species in southern regions survived and diverged without large geographical displacements. As a result of the importance of orography in much of the southern areas, such displacements must have involved populations ascending or descending mountains. The present study provides support for glacial‐induced altitudinal migrations from chloroplast phylogeographic patterns inArmeria(Plumbaginaceae) in southeast Spain. One hundred and five sequences of thetrnL‐Fspacer were obtained from seven species. Fifteen different haplotypes were recognized, their genealogy was inferred, and associations with geography were explored using nested clade analysis. Seven instances were detected in which the same haplotype is shared by two or three species within a particular massif. In all the cases, at least one of the species involved displayed different haplotypes in other areas; in most, the haplotype shared is predominant either in one of the species involved or in the massif. These patterns of haplotype sharing strongly suggest horizontal transfer between species. In one of the massifs (Sierra Nevada) the three species involved in haplotype sharing (A. splendens,A. filicaulisssp.nevadensis,A. villosassp.bernisii) occur at markedly different altitudinal belts. It is argued that altitudinal migrations within the contraction–expansion model provide the best explanation for the current pattern, and that at least in one case it resulted in the formation of a new hybrid taxon,A. filicaulisssp.nevadensis.
Diversity and geographic distribution of secondary endosymbiotic bacteria in natural populations of the pea aphid,Acyrthosiphon pisum
Authors: Tsuchida Tsutomu , Koga Ryuichi , Shibao Harunobu , Matsumoto Tadao , Fukatsu Takema 
Published: March 2003

AbstractIn addition to the essential intracellular symbiotic bacteriumBuchnera, several facultative endosymbiotic bacteria called collectively secondary symbionts (S‐symbionts) have been identified from the pea aphidAcyrthosiphon pisum. We conducted an extensive and systematic survey of S‐symbionts in Japanese local populations ofA. pisumusing a specific PCR detection technique. Five S‐symbionts ofA. pisum, PASS, PAUS, PABS,RickettsiaandSpiroplasma, and two facultative endosymbionts universally found in various insects,WolbachiaandArsenophonus, were targeted. Of 119 isofemale strains originating from 81 localities, 66.4% of the strains possessed either of four S‐symbionts: PASS (38.7%); PAUS (16.0%);Rickettsia(8.4%); andSpiroplasma(3.4%), while 33.6% of the strains contained onlyBuchnera. PABS,WolbachiaandArsenophonuswere not detected from the Japanese strains ofA. pisum. In order to understand intra‐ and interpopulational diversity of S‐symbiont microbiota in detail, 858 insects collected from 43 localities were examined for infection with the four S‐symbionts. It was demonstrated that different S‐symbionts coexist commonly in the same local populations, but double infections with two S‐symbionts were rarely detected. Notably, the S‐symbionts exhibited characteristic geographical distribution patterns: PASS at high frequencies all over Japan; PAUS at high frequencies mainly in the northeastern part of Japan; andRickettsiaandSpiroplasmaat low frequencies sporadically in the southwestern part of Japan. These results indicate that the geographical distribution and infection frequency of the S‐symbionts, in particular PAUS, might be affected by environmental and/or historical factors. Statistical analyses suggested that the distribution of PAUS infection might be related to host plant species, temperature and precipitation.
Multilocus population structure of Tapesia yallundae in Washington State
Authors: Douhan G. W. , Peever T. L. , Murray T. D. 
Published: March 2003

AbstractPopulation genetic structure of the fungal wheat pathogen Tapesia yallundae in Washington State was determined using genetically characterized amplified fragment length polymorphic (AFLP) markers and mating‐type (MAT1‐1 or MAT1‐2). Segregation and linkage relationships among 164 AFLP markers and MAT were analysed using 59 progeny derived from an in vitro cross. Alleles at 158 AFLP loci and the mating‐type locus segregated in a 1:1 ratio. Ten unlinked markers were chosen to determine genetic and genotypic diversity and to test the hypothesis of random mating and population differentiation among five subpopulations of T. yallundae representative of the geographical distribution of wheat production in eastern Washington. Among 228 isolates collected, overall gene diversity was high (h = 0.425) and a total of 91 unique multilocus genotypes (MLG) were identified, with 32 MLG occurring at least twice. The overall population genetic structure was consistent with random mating based on the segregation of mating‐type, index of association (IA), parsimony tree length permutation test (PTLPT) and genotypic diversity analyses. However, clonal genotypes were found within each subpopulation and were also distributed among the five subpopulations. No significant differences in allele frequencies were found among the five subpopulations for all 10 loci based on contingency table analysis (G2) and Wier & Cockerham's population differentiation statistic θ (θ = −0.008, P = 0.722). T. yallundae appears to consist of a large homogeneous population throughout eastern Washington with both sexual and asexual reproduction contributing to the observed population genetic structure despite no report of sexual fruiting bodies of T. yallundae occurring under natural field conditions.
Intraspecific phylogeography of the slender madtom: the complex evolutionary history of the Central Highlands of the United States
Authors: Hardy M. E. , Grady J. M. , Routman E. J. 
Published: March 2003

AbstractA number of different biogeographical studies of the Central Highlands of the United States have yielded conflicting area cladograms. We estimate the mtDNA phylogeny of populations of the slender madtom, Noturus exilis, a clear‐water stream catfish. The goal is to compare population relationships to those reported in previous studies that used upland, stream‐dwelling vertebrates. A region of the NADH dehydrogenase subunit 4 gene, along with adjacent tRNAs, was sequenced for population samples from 21 different Central Highlands rivers. Sequence difference among 39 haplotypes ranged from 0.1% to 4.8%. Most haplotypes were restricted to specific rivers and mapped well onto geography. Slender madtoms from different drainages contained mostly monophyletic groups of haplotypes genetically divergent from haplotypes found in other drainages, although a few haplotypes were found in well‐separated drainages. The area cladogram for the slender madtom was not similar to any of the other cladograms for other species and species groups from the area. We discuss a variety of methodological and biological reasons for the discordance, and suggest that some of the discrepancies may be resolved by the sequencing of multiple genes per species. We recommend that more, and more extensive, intraspecific phylogeography studies should be conducted for species living in the Central Highlands rivers.
Complex sociogenetic organization and reproductive skew in a primitively eusocial sweat bee,Lasioglossum malachurum, as revealed by microsatellites
Authors: Paxton Robert J. , Ayasse Manfred , Field Jeremy , Soro Antonella 
Published: March 2003

AbstractThe sweat bees (Family Halictidae) are a socially diverse taxon in which eusociality has arisen independently numerous times. The obligate, primitively eusocialLasioglossum malachurum, distributed widely throughout Europe, has been considered the zenith of sociality within halictids. A single queen heads a colony of smaller daughter workers which, by mid‐summer, produce new sexuals (males and gynes), of which only the mated gynes overwinter to found new colonies the following spring. We excavated successfully 18 nests during the worker‐ and gyne‐producing phases of the colony cycle and analysed each nest's queen and either all workers or all gynes using highly variable microsatellite loci developed specifically for this species. Three important points arise from our analyses. First, queens are facultatively polyandrous (queen effective mating frequency: range 1–3, harmonic mean 1.13). Second, queens may head colonies containing unrelated individuals (n= 6 of 18 nests), most probably a consequence of colony usurpation during the early phase of the colony cycle before worker emergence. Third, nonqueen's workers may, but the queen's own workers do not, lay fertilized eggs in the presence of the queen that successfully develop into gynes, in agreement with so‐called ‘concession’ models of reproductive skew.
Male production in stingless bees: variable outcomes of queen–worker conflict
Authors: Tóth Eva , Strassmann Joan E. , Nogueira‐Neto Paulo , Imperatriz‐Fonseca Vera L. , Queller David C. 
Published: March 2003

AbstractThe genetic structure of social insect colonies is predicted to affect the balance between cooperation and conflict. Stingless bees are of special interest in this respect because they are singly mated relatives of the multiply mated honeybees. Multiple mating is predicted to lead to workers policing each others’ male production with the result that virtually all males are produced by the queen, and this prediction is borne out in honey bees. Single mating by the queen, as in stingless bees, causes workers to be more related to each others’ sons than to the queen's sons, so they should not police each other. We used microsatellite markers to confirm single mating in eight species of stingless bees and then tested the prediction that workers would produce males. Using a likelihood method, we found some worker male production in six of the eight species, although queens produced some males in all of them. Thus the predicted contrast with honeybees is observed, but not perfectly, perhaps because workers either lack complete control or because of costs of conflict. The data are consistent with the view that there is ongoing conflict over male production. Our method of estimating worker male production appears to be more accurate than exclusion, which sometimes underestimates the proportion of males that are worker produced.