bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population structure in the endangered Mauna Loa silversword,Argyroxiphium kauense(Asteraceae), and its bearing on reintroduction
Authors: Friar E. A. , Boose D. L. , Ladoux T. , Roalson E. H. , Robichaux R. H. 
Published: March 2003

AbstractReintroduction of populations of endangered species is a challenging task, involving a number of environmental, demographic and genetic factors. Genetic parameters of interest include historical patterns of genetic structure and gene flow. Care must be taken during reintroduction to balance the contrasting risks of inbreeding and outbreeding depression. The Mauna Loa silversword,Argyroxiphium kauense, has experienced a severe decline in population size and distribution in the recent past. Currently, three populations with a total of fewer than 1000 individuals remain. We measured genetic variation within and among the remnant populations using seven microsatellite loci. We found significant genetic variation remaining within all populations, probably related to the recent nature of the population impact, the longevity of the plants, and their apparent self‐incompatibility. We also found significant genetic differentiation among the populations, reinforcing previous observations of ecological and morphological differentiation. With respect to reintroduction, the results suggest that, in the absence of additional data to the contrary, inbreeding depression may not be a substantial risk as long as propagules for the founding of new populations are adequately sampled from within each source population before additional inbreeding takes place. The results further suggest that if mixing of propagules from different source populations is not required to increase within‐population genetic variation in the reintroduced populations, it may best be avoided.
PCR‐based gut content analysis of insect predators: using ribosomal ITS‐1 fragments from prey to estimate predation frequency
Authors: Hoogendoorn Marlijn , Heimpel George E. 
Published: March 2003

AbstractWe used polymerase chain reaction to determine whether Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) DNA was present in the guts of larvae and adult males and females of the generalist predator Coleomegilla maculata De Geer (Coleoptera: Coccinellidae). The predators were fed Ostrinia nubilalis egg masses and allowed to digest at either 20 °C or 27 °C for time spans ranging from 0 to 12 h. Four primer pairs, specific for O. nubilalis were developed, using a nuclear ribosomal RNA sequence including part of the 18S gene, the complete internal transcribed spacer (ITS‐1) region and part of the 5.8S gene. These primers amplified four sequences that were 492, 369, 256 and 150 base pairs long. We found a significant negative effect of time since feeding on the number of bands that could be detected. The shortest fragment was detected for the longest time after feeding (up to 12 h). We found no effect of predator weight, sex, developmental stage, or meal size on the time course over which bands of varying lengths could be detected.
Diversity, genetic structure and evidence of outcrossing in British populations of the rock fern Adiantum capillus‐veneris using microsatellites
Authors: Pryor K. V. , Young J. E. , Rumsey F. J. , Edwards K. J. , Bruford M. W. , Rogers H. J. 
Published: March 2003

AbstractMicrosatellites were isolated and a marker system was developed in the fern Adiantum capillus‐veneris. Polymorphic markers were then used to study the genetic diversity and structure of populations within the UK and Ireland where this species grows at the northern edge of its range, requiring a specific rock habitat and limited to a few scattered populations. Three dinucleotide loci detected a high level of diversity (23 alleles and 28 multilocus genotypes) across the UK and Ireland, with nearly all variation partitioned among rather than within populations. Of 17 populations represented by multiple samples, all except four were monomorphic. Heterozygosity was detected in three populations, all within Glamorgan, Wales (UK), showing evidence of outcrossing. We make inferences on the factors determining the observed levels and patterns of genetic variation and the possible evolutionary history of the populations.
Provenance of a New Zealand brush‐tailed rock‐wallaby (Petrogale penicillata) population determined by mitochondrial DNA sequence analysis
Authors: Eldridge Mark D. B. , Browning Teena L. , Close Robert L. 
Published: March 2003

AbstractModern molecular genetic techniques provide a valuable means to address questions concerning the origins of naturalized populations. Brush‐tailed rock‐wallabies (Petrogale penicillata), of unknown provenance, were introduced to New Zealand from Australia in the early 1870s. While the introduced wallabies prospered in New Zealand, their antecedents in Australia experienced widespread local population extinctions as part of a drastic, widespread and ongoing decline. In this study, a polymerase chain reaction–single‐strand conformation polymorphism analysis was undertaken of mitochondrial DNA (mtDNA) control region sequences from P. penicillata in New Zealand (n = 18) and throughout the species’ native range in southeastern Australia (n = 54). A single mtDNA haplotype was identified in New Zealand, while 17 haplotypes were found in sampled Australian populations. Phylogenetic analysis (583 bp sequence) revealed the presence of three divergent mtDNA groups within Australian P. penicillata, with each group showing distinct geographical circumscription. The New Zealand haplotype consistently clustered within the central New South Wales group and was most similar (0.55% sequence divergence) to a haplotype from Winmalee, just west of Sydney. It seems likely then, that the New Zealand population of P. penicillata was founded by animals captured near Sydney in the late 19th century. Since P. penicillata in this region have experienced widespread population declines and extinctions, the naturalized New Zealand population represents a potentially valuable conservation resource for Australia. However, the unusual history of New Zealand’s P. penicillata presents unique challenges to Australian wildlife managers.
Multiple paternity in loggerhead turtle (Caretta caretta) nests on Melbourne Beach, Florida: a microsatellite analysis
Authors: Moore M. K. , Ball R. M. 
Published: March 2003

AbstractMany aspects of sea turtle biology are difficult to measure in these enigmatic migratory species, and this lack of knowledge continues to hamper conservation efforts. The first study of paternity in a sea turtle species used allozyme analysis to suggest multiple paternity in loggerhead turtle (Caretta caretta) clutches in Australia. Subsequent studies indicated that the frequency of multiple paternity varies from species to species and perhaps location to location. This study examined fine‐scale population structure and paternal contribution to loggerhead clutches on Melbourne Beach, FL, USA using microsatellite markers. Mothers and offspring from 70 nests collected at two locations were analysed using two to four polymorphic microsatellite loci. Fine‐scale population differentiation was not evident between the sampled locations, separated by 8 km. Multiple paternity was common in loggerhead nests on Melbourne Beach; 22 of 70 clutches had more than one father, and six had more than two fathers. This is the first time that more than two fathers have been detected for offspring in individual sea turtle nests. Paternal genotypes could not be assigned with confidence in clutches with more than two fathers, leaving the question of male philopatry unanswered. Given the high incidence of multiple paternity, we conclude that males are not a limiting resource for this central Florida nesting aggregate.
Estimating the long‐term effects of stocking domesticated trout into wild brown trout (Salmo trutta) populations: an approach using microsatellite DNA analysis of historical and contemporary samples
Authors: Hansen Michael M. 
Published: March 2003

AbstractIndigenous salmonid fish gene pools are affected by domesticated conspecifics, derived from aquaculture escapes and deliberate releases. Variability was examined at nine microsatellite loci in order to assess the long‐term impact of stocking domesticated trout in two brown trout populations. The study was based on analysis of two historical samples (1945–56), represented by old scale collections, and seven contemporary samples (1986–2000). In one population historical and contemporary samples were remarkably genetically similar despite more than a decade of intense stocking. Estimation of admixture proportions showed a small genetic contribution from domesticated trout (approximately 6%), and individual admixture analysis demonstrated a majority of nonadmixed individuals. The expected genetic contribution by domesticated trout was 64%, assessed from the number of stocked trout and assuming equal survival and reproductive performance of wild and domesticated trout. This demonstrates poor performance and low fitness of domesticated trout in the wild. In another population there was a strong genetic contribution from domesticated trout (between 57% and 88% in different samples), both in samples from a broodstock thought to represent the indigenous population and in a sample of wild spawners. Survival of domesticated trout and admixture with indigenous fish in the broodstock and subsequent stocking into the river, combined with a low population size of native trout relative to the number of stocked trout, could explain the observed introgression. Few nonadmixed individuals remained in the introgressed population, and I discuss how individual admixture analysis can be used to identify and conserve nonintrogressed remains of the population.
The impact of stocking on the genetic integrity of Arctic charr (Salvelinus) populations from the Alpine region
Authors: Englbrecht Claudia C. , Schliewen Ulrich , Tautz Diethard 
Published: March 2003

AbstractThere is a long tradition of artificially stocking lakes and rivers with fish in the hope to increase the quality and amount of fish that can be harvested. The animals used for stocking often originate in distant hatcheries or hatcheries that breed fish from remote regions. This stocking practice could have effects on the genetic integrity of resident populations. We have analysed here a case of the influence of stocking on Alpine populations of the Arctic charr (usually included into Salvelinus alpinus, but revised to Salvelinus umblaKottelat 1997) within a unique geographical and historical setting. The Königssee in the Bavarian Alps (Berchtesgaden) was heavily stocked several times during the last century. However, a sample of the ancestral Königssee population still exists in the Grünsee, which lies close to Königssee, but 1000 m higher. To trace the influence of stocking in Königssee we have analysed more than 300 individuals from 10 lake populations, including the source populations of the fish used for stocking. From these we have sequenced a part of the mitochodrial control region and have typed them at six microsatellite loci. The differential distribution of haplotypes, as well as assignment tests, show that the influence of stocking on the genetic integrity of the Königssee population has been negligible. However, our data reveal that in another lake included in our study (Starnberger See), the ancestral population was apparently replaced completely by the populations used for stocking. The major difference between the lakes is the relative preservation of ecological integrity. Königssee was ecologically stable in the past, whereas Starnberger See was heavily polluted at one point, with charr approaching extinction. Interestingly, in a lake neighbouring Starnberger See, the Ammersee, which was also subject to strong pollution but not stocked, the ancestral population has recovered. Our data suggest that the practice of artificial stocking should be reconsidered, or at least monitored for effectiveness.
A distinct Bemisia tabaci (Gennadius) (Hemiptera: Sternorrhyncha: Aleyrodidae) genotype cluster is associated with the epidemic of severe cassava mosaic virus disease in Uganda
Authors: Legg J. P. , French R. , Rogan D. , Okao‐Okuja G. , Brown J. K. 
Published: March 2003

AbstractDuring the 1990s, an epidemic of cassava mosaic virus disease caused major losses to cassava production in Uganda. Two factors associated with the epidemic were the occurrence of a novel recombinant begomovirus, EACMV‐Ug, and unusually high populations of the whitefly vector, Bemisia tabaci. Here we present molecular evidence for the occurrence of two cassava‐colonizing B. tabaci genotype clusters, Ug1 and Ug2, one of which, Ug2, can be consistently associated with the CMD epidemic in Uganda at the time of collection in 1997. By contrast, a second genotype cluster, Ug1, only occurred ‘at’ or ‘ahead of’ the epidemic ‘front’, sometimes in mixtures with Ug2. Comparison of mitochondrial cytochrome oxidase I gene sequences for Ug1 and Ug2 and well‐studied B. tabaci reference populations indicated that the two Ugandan populations exhibited ≈ 8% divergence, suggesting they represent distinct sub‐Saharan African lineages. Neither Ugandan genotype cluster was identified as the widely distributed, polyphagous, and highly fecund B biotype of Old World origin, with which they both diverged by ≈ 8%. Within genotype cluster divergence of Ug1 at 0.61 ± 0.1% was twice that of Ug2 at 0.35 ± 0.1%. Mismatch analysis suggested that Ug2 has undergone a recent population expansion and may be of nonUgandan origin, whereas Ug1 has diverged more slowly, and is likely to be an indigenous genotype cluster.
Speciation and the establishment of zonation in an intertidal barnacle: specific settlement vs. selection*
Authors: Appelbaum L. , Achituv Y. , Mokady O. 
Published: March 2003

AbstractThe tropical barnacle Tetraclita forms a belt on hard substrates in the intertidal zone of the Red Sea. Based on morphological data, three distinct species were suggested to exist, occupying different vertical levels — T. barnesorum, T. rufotincta and T. achituvi. In this study we used molecular (12S mitochondrial ribosomal DNA) and ecological data to examine whether this morphological variability reflects genetic differences, or is a result of environmental factors. Adults and spats, collected from settlement plates, were censused and screened genotypically using single strand conformation polymorphism (SSCP) analysis, and settlement dynamics was recorded. We provide evidence for the existence of only two distinct species, and point out both phenotypic plasticity and convergence within and between the proposed species. Cyprids of T. achituvi settle specifically at the lower part of the Tetraclita belt, and feature one phenotype. In contrast, T. rufotincta, occupying the upper and middle portions of the Tetraclita belt, settles throughout the range, shows phenotypic plasticity (three variants), and presumably undergoes selection at the lower part. Thus, the vertical zonation of Tetraclita is produced by the combination of pre‐settlement and post‐settlement factors, in T. achituvi and T. rufotincta, respectively. The examined system may offer a model in which to study the mechanisms underlying sympatric speciation.
DNA sequence and RFLP data reflect geographical spread and relationships of Amylostereum areolatum and its insect vectors
Authors: Slippers B. , Wingfield B. D. , Coutinho T. A. , Wingfield M. J. 
Published: March 2003

AbstractThe white rot fungus, Amylostereum areolatum (Basidiomycetes), is best known for its symbiotic relationship with various siricid wood wasp species. In this study, the relationship between isolates of A. areolatum associated with two wood wasp species, Sirex noctilio and S. juvencus, are considered to identify possible intraspecific groups. Isolates from the northern (native) and southern (exotic) hemispheres are included to determine patterns of geographical spread and origin of introductions into the southern hemisphere. The phylogenetic relationships of these isolates to authentic isolates of A. chailletii, A. laevigatum and A. ferreum were also investigated. Sequence and restriction fragment length polymorphism (RFLP) analyses of the variable nuc‐IGS‐rDNA region provided markers to distinguish intraspecific groups within A. areolatum. Isolates of A. areolatum associated with S. noctilio and S. juvencus contained four heterogenic sequences in the DNA region analysed. These sequences occurred in one of five combinations in each isolate. Some of these sequences were unique to isolates of A. areolatum from either wasp species, while others were present in both groups. This shows the ancient and specialized evolutionary relationship that exists between these insects and fungi. Isolates from the southern hemisphere all share the same sequence group. This supports previous hypotheses that S. noctilio has spread between countries and continents of this region. At the interspecific level, the IGS‐rDNA sequence analysis showed that A. ferreum and A. laevigatum are closely related to each other, and they in turn are related to A. chailletii. Amylostereum areolatum was the most distinctly defined species in the genus. This can be attributed to the obligate relationship between A. areolatum and its insect vectors. Polymerase chain reaction‐RFLP analysis was also shown to be an effective tool to distinguish between the different species of Amylostereum.
Pollen movement in declining populations of California Valley oak, Quercus lobata: where have all the fathers gone?
Authors: Sork V. L. , Davis F. W. , Smouse P. E. , Apsit V. J. , Dyer R. J. , Fernandez‐M J. F. , Kuhn B. 
Published: March 2003

AbstractThe fragmented populations and reduced population densities that result from human disturbance are issues of growing importance in evolutionary and conservation biology. A key issue is whether remnant individuals become reproductively isolated. California Valley oak (Quercus lobata) is a widely distributed, endemic species in California, increasingly jeopardized by anthropogenic changes in biota and land use. We studied pollen movement in a savannah population of Valley oak at Sedgwick Reserve, Santa Barbara County, to estimate effective number of pollen donors (Nep) and average distance of effective pollen movement (δ). Usingtwogener, our recently developed hybrid model of paternity and genetic structure treatments that analyses maternal and progeny multilocus genotypes, we found that currentNep = 3.68 individuals. Based on an average adult density ofd= 1.19 stems/ha, we assumed a bivariate normal distribution to model current average pollen dispersal distance (δ) and estimated δ= 64.8 m. We then deployed our parameter estimates in spatially explicit models of the Sedgwick population to evaluate the extent to whichNepmay have changed, as a consequence of progressive stand thinning between 1944 and 1999. Assuming that pollen dispersal distance has not changed, we estimateNepwas 4.57 individuals in 1944, when stand density was 1.48. Both estimates indicate fewer effective fathers than one might expect for wind‐pollinated species and fewer than observed elsewhere. The results presented here provide a basis for further refinements on modelling pollen movement. If the trends continue, then ongoing demographic attrition could further reduce neighbourhood size in Valley oak resulting in increased risk of reproductive failure and genetic isolation.
Confirmation of low genetic diversity and multiple breeding females in a social group of Eurasian badgers from microsatellite and field data
Authors: Domingo‐Roura X. , Macdonald D. W. , Roy M. S. , Marmi J. , Terradas J. , Woodroffe R. , Burke T. , Wayne R. K. 
Published: March 2003

AbstractThe Eurasian badger (Meles meles) is a facultatively social carnivore that shows only rudimentary co‐operative behaviour and a poorly defined social hierarchy. Behavioural evidence and limited genetic data have suggested that more than one female may breed in a social group. We combine pregnancy detection by ultrasound and microsatellite locus scores from a well‐studied badger population from Wytham Woods, Oxfordshire, UK, to demonstrate that multiple females reproduce within a social group. We found that at least three of seven potential mothers reproduced in a group that contained 11 reproductive age females and nine offspring. Twelve primers showed variability across the species range and only five of these were variable in Wytham. The microsatellites showed a reduced repeat number, a significantly higher number of nonperfect repeats, and moderate heterozygosity levels in Wytham. The high frequency of imperfect repeats and demographic phenomena might be responsible for the reduced levels of variability observed in the badger.
Widespread occurrence of a domestic dog mitochondrial DNA haplotype in southeastern US coyotes
Authors: Adams J. R. , Leonard J. A. , Waits L. P. 
Published: March 2003

AbstractSequence analysis of the mitochondrial DNA control region from 112 southeastern US coyotes (Canis latrans) revealed 12 individuals with a haplotype closely related to those in domestic dogs. Phylogenetic analyses grouped this new haplotype in the dog/grey wolf (Canis familiaris/Canis lupus) clade with 98% bootstrap support. These results demonstrate that a male coyote hybridized with a female dog, and female hybrid offspring successfully integrated into the coyote population. The widespread distribution of this haplotype from Florida to West Virginia suggests that the hybridization event occurred long ago before the southeastern USA was colonized by coyotes. However, it could have occurred in the southeastern USA before the main front of coyotes arrived in the area between male coyotes released for sport and a local domestic dog. The introgression of domestic dog genes into the southeastern coyote population does not appear to have substantially affected the coyote's genetic, morphological, or behavioural integrity. However, our results suggest that, contrary to previous reports, hybridization can occur between domestic and wild canids, even when the latter is relatively abundant. Therefore, hybridization may be a greater threat to the persistence of wild canid populations than previously thought.
Mitochondrial haplotype distribution, seed dispersal and patterns of postglacial expansion of ponderosa pine
Authors: Johansen A. D. , Latta R. G. 
Published: March 2003

AbstractMaternally inherited mtDNA in a secondary contact zone of ponderosa pine revealed a cline less than 10 km wide — much narrower than previously described. A survey of 76 populations gave no evidence either of intermixing or of a mosaic contact zone. Such sharp contact zones are consistent with diffusive range expansion, rather than long distance colonization. However, evidence for long distance seed dispersal events was found in two populations where haplotypes were observed far from their main area of occurrence. The results suggest a small number of long distance colonists with diffusive dispersal from these centres.