bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microspatial genetic heterogeneity and gene flow in stray cats (Felis catus L.): a comparison of coat colour and microsatellite loci
Authors: Say Ludovic , Bonhomme François , Desmarais Eric , Pontier Dominique 
Published: May 2003

AbstractWe analysed levels of genetic differentiation between nine local urban colonies of stray cats using eight coat colour and nine microsatellite loci. Both types of markers revealed a strong differentiation between colonies (FST = 0.15 and 0.09 for coat colour and microsatellite loci, respectively). Three coat colour loci showed extreme levels of genetic differentiation comparatively to other loci and are strongly suspected to be under divergent selective pressures. Microsatellite loci showed significant heterozygote deficiency within colonies (FIS = 0.14), suggesting that coat colour loci are not appropriate to investigate genetic structure at a fine scale because coat colour allele frequencies are based on Hardy–Weinberg equilibrium. The reported pattern conformed to that predicted from the social structuring of cat colonies: aggressive exclusion of immigrants, inbreeding and very low dispersal rate.
How much effort is required to isolate nuclear microsatellites from plants?
Authors: Squirrell J. , Hollingsworth P. M. , Woodhead M. , Russell J. , Lowe A. J. , Gibby M. , Powell W. 
Published: May 2003

AbstractThe attributes of codominance, reproducibility and high resolution have all contributed towards the current popularity of nuclear microsatellites as genetic markers in molecular ecological studies. One of their major drawbacks, however, is the development phase required to obtain working primers for a given study species. To facilitate project planning, we have reviewed the literature to quantify the workload involved in isolating nuclear microsatellites from plants. We highlight the attrition of loci at each stage in the process, and the average effort required to obtain 10 working microsatellite primer pairs.
Fluorescencein situhybridization: a new method for determining primary sex ratio in ants
Authors: De Menten L. , Niculita H. , Gilbert M. , Delneste D. , Aron S. 
Published: May 2003

AbstractThe haplodiploid sex determining system in Hymenoptera, whereby males develop from haploid eggs and females from diploid eggs, allows females to control the primary sex ratio (the proportion of each sex at oviposition) in response to ecological and/or genetic conditions. Surprisingly, primary sex ratio adjustment by queens in eusocial Hymenoptera has been poorly studied, because of difficulties in sexing the eggs laid. Here, we show that fluorescencein situhybridization (FISH) can be used to accurately determine the sex (haploid or diploid) of eggs, and hence the primary sex ratio, in ants. We first isolated the homologue coding sequences of theabdominal‐Agene from 10 species of 8 subfamilies of Formicidae. Our data show that the nucleotide sequence of this gene is highly conserved among the different subfamilies. Second, we used a sequence of 4.5 kbp from this gene as a DNA probe for primary sex ratio determination by FISH. Our results show that this DNA probe hybridizes successfully with its complementary DNA sequence in all ant species tested, and allows reliable determination of the sex of eggs. Our proposed method should greatly facilitate empirical tests of primary sex ratio in ants.
Genetic consequences of the ice ages on nurseries of the bat Myotis myotis: a mitochondrial and nuclear survey
Authors: Ruedi M. , Castella V. 
Published: May 2003

AbstractAnalyses of mitochondrial DNA (mtDNA) control region polymorphism and of variation at 10 nuclear microsatellite loci were used to investigate the mechanisms and genetic consequences of postglacial expansion of Myotis myotis in Europe. Initial sampling consisted of 480 bats genotyped in 24 nursery colonies arranged along a transect of ≈ 3000 km. The phylogeographical survey based on mtDNA sequences revealed the existence of major genetic subdivisions across this area, with several suture zones between haplogroups. Such zones of secondary contact were found in the Alps and Rhodopes, whereas other potential barriers to gene flow, like the Pyrenees, did not coincide with genetic discontinuities. Areas of population admixture increased locally the genetic diversity of colonies, which confounded the northward decrease in nucleotide diversity predicted using classical models of postglacial range expansion. However, when analyses were restricted to a subset of 15 nurseries originating from a single presumed glacial refugium, mtDNA polymorphism did indeed support a northwards decrease in diversity. Populations were also highly structured (ΦST = 0.384). Conversely, the same subset of colonies showed no significant latitudinal decrease in microsatellite diversity and much less population structure (FST = 0.010), but pairwise genetic differentiation at these nuclear markers was strongly correlated with increasing geographical distance. Together, this evidence suggests that alleles carried via male bats have maintained enough nuclear gene flow to counteract the effects of recurrent bottlenecks generally associated with recolonization processes. As females are highly philopatric, we argue that the maternally transmitted mtDNA marker better reflects the situation of past, historical gene flow, whereas current levels of gene flow are better reflected by microsatellite markers.
Population genetic structure of the toadBufo woodhousii: an empirical assessment of the effects of haplotype extinction on nested cladistic analysis
Authors: Masta S. E. , Laurent N. M. , Routman E. J. 
Published: May 2003

AbstractNested cladistic analysis (NCA) is increasingly being used to infer historical population‐level processes, including population fragmentation, range expansion and long‐distance colonization. However, the effects on interpretation of NCA inferences of stochastic extinction of haplotypes due to genetic drift (lineage sorting), or of haplotype loss via localized biotic or climatic influences, have not been thoroughly explored. We provide empirical evidence suggesting that NCA may misinterpret population history when haplotypes or haplotype groups from one clade are replaced by those of another clade. We do so by using NCA to analyse mitochondrial sequences from the toadBufo woodhousiifrom 45 locations spanning the Great Plains and southwestern USA. Portions of this region were glaciated and/or desertified in the late Pleistocene and early Holocene, and hence uninhabitable for plains‐dwelling organisms. Although NCA inferences of isolation‐by‐distance and gradual range expansion inB. woodhousiiare compatible with expectations based on climatic data and toad biology, NCA also detected several instances of long‐distance movement. Such movement seems unlikely, given the low vagility of this species. We conclude that inferences of long‐distance colonization likely result from extinction of haplotypes in intervening areas. We suggest using additional methods to look for congruent inferences, and amending the NCA inference key, to help avoid misinterpretations resulting from haplotype extinction.
Early male reproductive advantage, multiple paternity and sperm storage in an amphibian aggregate breeder
Authors: Tennessen J. A. , Zamudio K. R. 
Published: May 2003

AbstractWe tested whether the order in which males encounter females affects reproductive fitness in spotted salamanders (Ambystoma maculatum). Using mating chambers in the field, we allowed one male access to a female before a second male. We then used four microsatellite markers in paternity analyses of the resulting larvae. First males sired a significantly larger number of offspring than second males, suggesting that male reproductive success is greatly enhanced by early arrival at breeding ponds. Multiple paternity was common among clutches, and frequently larvae were assigned to unidentified males that had not been in the chambers. Sperm from these males had either been stored by females for a year or obtained more recently at other breeding sites.
Estimation of pairwise relatedness between individuals and characterization of isolation‐by‐distance processes using dominant genetic markers
Authors: Hardy Olivier J. 
Published: May 2003

AbstractA new estimator of the pairwise relatedness coefficient between individuals adapted to dominant genetic markers is developed. This estimator does not assume genotypes to be in Hardy–Weinberg proportions but requires a knowledge of the departure from these proportions (i.e. the inbreeding coefficient). Simulations show that the estimator provides accurate estimates, except for some particular types of individual pairs such as full‐sibs, and performs better than a previously developed estimator. When comparing marker‐based relatedness estimates with pedigree expectations, a new approach to account for the change of the reference population is developed and shown to perform satisfactorily. Simulations also illustrate that this new relatedness estimator can be used to characterize isolation by distance within populations, leading to essentially unbiased estimates of the neighbourhood size. In this context, the estimator appears fairly robust to moderate errors made on the assumed inbreeding coefficient. The analysis of real data sets suggests that dominant markers (random amplified polymorphic DNA, amplified fragment length polymorphism) may be as valuable as co‐dominant markers (microsatellites) in studying microgeographic isolation‐by‐distance processes. It is argued that the estimators developed should find major applications, notably for conservation biology.
Checking the geographical origin of oak wood: molecular and statistical tools
Authors: Deguilloux M. F. , Pemonge M. H. , Bertel L. , Kremer A. , Petit R. J. 
Published: May 2003

AbstractNew methods for better identification of timber geographical origin would constitute an important technical element in the forest industry, for phytosanitary certification procedures or in the chain of custody developed for the certification of timber from sustainably managed forests. In the case of the European white oaks, a detailed reference map of chloroplast (cp) DNA variation across the range exists, and we propose here to use the strong geographical structure, characterized by a differentiation of western vs. eastern populations, for the purpose of oak wood traceability. We first developed cpDNA markers permitting the characterization of haplotype on degraded DNA obtained from wood samples. The techniques were subsequently validated by confirming the full correspondence between genotypes obtained from living tissues (buds) and from wood collected from the same individual oak. Finally, a statistical procedure was used to test if the haplotype composition of a lot of wood samples is consistent with its presumed geographical origin. Clearly, the technique cannot permit the unambiguous identification of wood products of unknown origin but can be used to check the conformity of genetic composition of wood samples with the region of alleged origin. This could lead to major applications not only in the forest industry but also in archaeology or in palaeobotany.
Characterization of Pacific golden chanterelle (Cantharellus formosus) genet size using co‐dominant microsatellite markers
Authors: Dunham S. M. , Kretzer A. , Pfrender M. E. 
Published: May 2003

AbstractWe characterized five co‐dominant microsatellite markers and used them to study Pacific golden chanterelle (Cantharellus formosus) genet size and its relation to forest age and disturbance. Fruit‐bodies were mapped in and collected from nine replicate study plots in old‐growth, recently thinned, and unthinned 40–60‐year‐old second‐growth stands dominated by Douglas fir (Pseudotsuga menziesii). Information from microsatellite loci, combined with random fragment length polymorphism analysis of the nuclear DNA internal transcribed spacer indicates that putative ‘C. formosus’ fruit‐body collections may include a cryptic chanterelle species. Small genets were characterized for both genetic types with mean maximum widths of 3.2 ± 3.6 m for C. formosus and 1.5 ± 1.7 m for the alternative genetic group. Variance in genet size was high and some multilocus genotypes were observed on multiple plots separated by 0.3 km or more, indicating that genets were not fully resolved by the loci described here. There was no evidence that genet size differed across the three disturbance treatments.
Queen control over reproductive decisions — no sexual deception in the ant Lasius niger
Authors: Jemielity Stephanie , Keller Laurent 
Published: May 2003

AbstractQueen–worker conflicts in social insect societies have received much attention in the past decade. In many species workers modify the colony sex ratio to their own advantage or produce their own male offspring. In some other species, however, queens seem to be able to prevent workers from making selfish reproductive decisions. So far, little effort has been made to find out how queens may keep control over sex ratio and male parentage. In this study we use a Lasius niger population under apparent queen control to show that sexual deception cannot explain queen dominance in this population. The sexual deception hypothesis postulates that queens should prevent workers from discriminating against males by disguising male brood as females. Contrary to the predictions of this hypothesis, we found that workers are able to distinguish male and female larvae early in their development: in early spring workers generally placed only either female or male larvae in the uppermost chambers of the nest, although both types of larvae must have been present. At this time males were only at 11% of their final dry weight, a developmental stage at which (according to two models) workers would still have benefited from replacing queen‐produced males by females or worker‐produced males. This study thus demonstrates that sexual deception cannot account for the apparent queen control over colony sex ratio and male parentage in L. niger.
The influence of the Miocene Mediterranean desiccation on the geographical expansion and genetic variation of Androcymbium gramineum (Cav.) McBride (Colchicaceae)
Authors: Caujapé‐Castells Juli , Jansen Robert K. 
Published: May 2003

AbstractChloroplast DNA (cpDNA) restriction site and isozyme data were combined to explore the spatial–temporal influence of the Messinian desiccation in the Mediterranean on the disjunct distribution of Androcymbium gramineum in Almería and Morocco (north and south of the straits of Gibraltar, respectively). Lack of evidence for different selective pressures, divergence time estimates based on the calibration of the isozyme molecular clock with the cpDNA data, the basal position of Almerian populations in the A. gramineum clade, and the much higher isozyme polymorphism in Almería suggest that (i) only a southern European range of A. gramineum existed before the Messinian [≈ 11.2 million years ago (Ma), in the middle Miocene] and (ii) the desiccation of the Mediterranean basin about 5.5–4.5 Ma induced the migration of A. gramineum from Almería to Morocco (between 4.9 and 4.6 Ma, according to our time estimates). After the split into two allopatric units following the refilling of the Mediterranean, the major influence of drift associated with Plio‐Pleistocene recurrent glaciation cycles and range expansions/contractions probably fostered the substantial interpopulation genetic differentiation observed within Almería (CGST = 0.41, average DNei = 0.185) and, to a lesser extent, within Morocco (CGST = 0.24, average DNei = 0.089), but did not hinder the maintenance of considerable levels of genetic variation in either geographical area (A = 2.14, HE = 0.230 and A = 1.90, HE = 0.213, respectively).
Queen‐controlled sex ratios and worker reproduction in the bumble bee Bombus hypnorum, as revealed by microsatellites
Authors: Brown M. J. F. , Schmid‐Hempel R. , Schmid‐Hempel P. 
Published: May 2003

AbstractSocial insect colonies provide model systems for the examination of conflicts among parties with different genetic interests. As such, they have provided the best tests of inclusive fitness theory. However, much remains unknown about in which party's favour such conflicts are resolved, partly as a result of the only recent advent of the molecular tools needed to examine the outcome of these conflicts. Two key conflicts in social insect colonies are over control of the reproductive sex ratio and the production of male offspring. Most studies have examined only one of these conflicts but in reality they occur in tandem and may influence each other. Using microsatellite analyses, the outcome of conflict over sex ratios and male production was examined in the bumble bee, Bombus hypnorum. The genotypes were determined for mother queens, their mates and males for each of 10 colonies. In contrast to other reports of mating frequency in this species, all of the queens were singly mated. The population sex ratio was consistent with queen control, suggesting that queens are winning this conflict. In contrast, workers produced over 20% of all males in queen‐right colonies, suggesting that they are more effective in competing over male‐production. Combining these results with previous work, it is suggested that worker reproduction is a labile trait that may well impose only small costs on queen fitness.
Was there a second adaptive radiation of giant tortoises in the Indian Ocean? Using mitochondrial DNA to investigate speciation and biogeography of Aldabrachelys (Reptilia, Testudinidae)
Authors: Austin Jeremy J. , Arnold E. Nicholas , Bour Roger 
Published: May 2003

AbstractA radiation of five species of giant tortoises (Cylindraspis) existed in the southwest Indian Ocean, on the Mascarene islands, and another (of Aldabrachelys) has been postulated on small islands north of Madagascar, from where at least eight nominal species have been named and up to five have been recently recognized. Of 37 specimens of Madagascan and small‐island Aldabrachelys investigated by us, 23 yielded significant portions of a 428‐base‐pair (bp) fragment of mitochondrial (cytochrome b and tRNA‐Glu), including type material of seven nominal species (A. arnoldi, A. dussumieri, A. hololissa, A. daudinii, A. sumierei, A. ponderosa and A. gouffei). These and nearly all the remaining specimens, including 15 additional captive individuals sequenced previously, show little variation. Thirty‐three exhibit no differences and the remainder diverge by only 1–4 bp (0.23–0.93%). This contrasts with more widely accepted tortoise species which show much greater inter‐ and intraspecific differences. The non‐Madagascan material examined may therefore only represent a single species and all specimens may come from Aldabra where the common haplotype is known to occur. The present study provides no evidence against the Madagascan origin for Aldabra tortoises suggested by a previous molecular phylogenetic analysis, the direction of marine currents and phylogeography of other reptiles in the area. Ancient mitochondrial DNA from the extinct subfossil A. grandidieri of Madagascar differs at 25 sites (5.8%) from all other Aldabrachelys samples examined here.
Edaphic races and phylogenetic taxa in the Lasthenia californica complex (Asteraceae: Heliantheae): an hypothesis of parallel evolution
Authors: Rajakaruna Nishanta , Baldwin Bruce G. , Chan Raymund , Desrochers Andrée M. , Bohm Bruce A. , Whitton Jeannette 
Published: May 2003

Abstract Lasthenia californica sensu Ornduff consists of two races that differ in their flavonoid pigments and edaphic tolerances. Recent phylogenetic studies of Lasthenia have revealed that members of L. californica sensu Ornduff belong to two phylogenetic species. The relationship of the edaphic races to these new species and to each other is the focus of this study. Characterization of flavonoid profiles and phylogenetic placement of 33 populations demonstrates that races and phylogenetic taxa are not concordant, suggesting that one or both edaphic races evolved in parallel in the two clades. We hypothesize an edaphically linked ecological role for flavonoid differences that first revealed the existence of two races.
High multiple paternity and low last‐male sperm precedence in a hermaphroditic planarian flatworm: consequences for reciprocity patterns
Authors: Pongratz N. , Michiels N. K. 
Published: May 2003

AbstractIt is difficult to predict a priori how mating success translates into fertilization success in simultaneous hermaphrodites with internal fertilization. Whereas insemination decisions will be determined by male interests, fertilization will depend on female interests, possibly leading to discrepancies between insemination and fertilization patterns. The planarian flatworm Schmidtea polychroa, a simultaneous hermaphrodite in which mating partners trade sperm was studied. Sperm can be stored for months yet individuals mate frequently. Using microsatellites, maternity and paternity data were obtained from 748 offspring produced in six groups of 10 individuals during four weeks. Adults produced young from four mates on average. Reciprocal fertilization between two mates was found in only 41 out of 110 registered mate combinations, which is clearly less than what is predicted from insemination patterns. Multiple paternity was high: > 80% of all cocoons had two to five fathers for only three to five offspring per cocoon. Because animals were collected from a natural population, 28% of all hatchlings were sired by unknown sperm donors in the field, despite a 10‐day period of acclimatization and within‐group mating. This percentage decreased only moderately throughout the experiment, showing that sperm can be stored and used for at least a month, despite frequent mating and sperm digestion. The immediate paternity a sperm donor could expect to obtain was only about 25%. Male reproductive success increased linearly with the number of female partners, providing support for Bateman's principle in hermaphrodites. Our results suggest that hermaphrodites do not trade fertilizations when trading sperm during insemination, lending support to the view that such conditional sperm exchange is driven by exchange of resources.
Measuring gene flow from two birdsfoot trefoil (Lotus corniculatus) field trials using transgenes as tracer markers
Authors: De Marchis F. , Bellucci M. , Arcioni S. 
Published: May 2003

AbstractGenetic engineering is becoming a useful tool in the improvement of plants but concern has been expressed about the potential environmental risks of releasing genetically modified (GM) organisms into the environment. Attention has focused on pollen dispersal as a major issue in the risk assessment of transgenic crop plants. In this study, pollen‐mediated dispersal of transgenes via cross‐fertilization was examined. Plants of Lotus corniculatus L. transformed with either the Escherichia coli asparagine synthetase gene asnA or the β‐glucuronidase gene uidA, were used as the pollen donor. Nontransgenic plants belonging to the species L. corniculatus L., L. tenuis Waldst. and Kit. ex Willd, and L. pedunculatus Cav., were utilized as recipients. Two experimental fields were established in two areas of central Italy. Plants carrying the uidA gene were partially sterile, therefore only the asnA gene was used as a tracer marker. No transgene flow between L. corniculatus transformants and the nontransgenic L. tenuis and L. pedunculatus plants was detected. As regards nontransgenic L. corniculatus plants, in one location flow of asnA transgene was detected up to 18 m from the 1.8 m2 donor plot. In the other location, pollen dispersal occurred up to 120 m from the 14 m2 pollinating plot.