bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversion of Anopheles gambiae from children to other hosts following exposure to permethrin‐treated bednets
Authors: Quiñones M. L. , Drakeley C. J. , Müller O. , Lines J. D. , Haywood M. , Greenwood B. M.
Published: March 2003

Permethrin‐treated bednets reduce mortality and morbidity from malaria in Gambian children. However, it is not certain how this effect is achieved, as neither mosquito numbers nor the human blood index of indoor‐resting female Anopheles gambiae Giles sensu lato (Diptera: Culicidae) mosquitoes have been reduced when treated bednets were introduced into a community. One possibility is that insecticide‐treated bednets divert mosquitoes from children to adults. To investigate this hypothesis, a cross‐over trial with insecticide‐treated bednets was undertaken in two small Gambian villages. To differentiate mosquitoes that had fed on children from those that had fed on adults, all children in the study villages were immunized with rabies vaccine before the trial. Using the detection of rabies antibody in a bloodmeal as an indicator that a mosquito had bitten a child, it was found that the percentage of blood‐fed mosquitoes caught indoors that had bitten a child fell significantly from 30.8% to 9.2% and from 28.0% to 6.9% in each village after insecticide‐treated bednets were introduced. To investigate the possibility that some diversion to animals had occurred, a PCR analysis for human β‐globin DNA was undertaken on selected samples. The results of this investigation were confusing, as some rabies‐antibody positive bloodmeals were negative for human DNA. This may have been due to cross‐reacting antibodies in animal sera and/or DNA degradation by digestion in the mosquito. Although good evidence for diversion of mosquitoes away from children was obtained, it remains uncertain whether diversion was mainly to adult humans, to animals or to both.
Abiotic factors influencing the ecology of wild rabbit fleas in north‐eastern Spain
Authors: Osacar‐Jimenez J. J. , Lucientes‐Curdi J. , Calvete‐Margolles C.
Published: March 2003

During 1992, the population dynamics of rabbit fleas were compared at two sites in north‐eastern Spain. The sites differed mainly in terms of annual rainfall and soil type. All flea species showed seasonal cycles of abundance, although peaks in numbers occurred at different times, reflecting their specific adaptations for coping with climatic variables. Adult Spilopsyllus cuniculi (Dale) (Siphonaptera: Pulicidae) were found largely parasitizing rabbits in spring and adult Caenopsylla laptevi (Beaucournu et al. ) (Siphonaptera: Ceratophyllidae) in the autumn. In contrast, monthly flea indices of Xenopsylla cunicularis (Smit) (Siphonaptera: Pulicidae) and Echidnophaga iberica (Ribeiro et al. ) (Siphonaptera: Pulicidae) peaked in summer. Spilopsyllus cuniculi was present at both sites, but was less common on the drier site, where monthly mean temperature and annual rainfall approached the flea's physiological limits. By contrast, E. iberica, X. cunicularis and C. laptevi, known to be better adapted for dryness, showed the opposite patterns of abundance. Nevertheless, even these arid‐adapted species took advantage of the milder and wetter spring (X. cunicularis and E. iberica) or autumn (C. laptevi) for breeding and larval development. Although environmental temperature, rainfall and soil texture will influence the microclimate of the burrows where the flea larvae develop, burrow humidity seems to be more dependent on soil characteristics and past rainfall rather than the humidity of the external air.
Completion of the sequence of the nuclear ribosomal DNA subunit of Simulium sanctipauli, with descriptions of the 18S, 28S genes and the IGS
Authors: Morales‐Hojas R. , Post R. J. , Wilson M. D. , Cheke R. A.
Published: March 2003

Abstract We describe the IGS‐ETS, 18S and 28S ribosomal gene sequences of Simulium sanctipauli Vajime & Dunbar, a member of the S. damnosum Theobald (Diptera: Simuliidae) complex of blackflies (Diptera: Simuliidae). These regions, together with the ITS‐1, ITS‐2 and 5.8S rDNA presented elsewhere (accession number U36206), constitute the composite sequence of the entire rDNA unit, making S. sanctipauli the second dipteran species of medical importance for which the entire rDNA has been sequenced. Despite the lack of sequence identity, the IGS of S. sanctipauli showed some structural similarities to other Diptera, i.e. the mosquito Aedes albopictus Skuse (Culicidae), the fruitfly Drosophila melanogaster Meigen (Drosophilidae) and the tsetse Glossina (Glossinidae). Two blocks of tandemly repeated subunits were present in the IGS of S. sanctipauli and, unlike other species of Diptera, they contained no duplications of promoter‐like sequences. However, two promoter‐like sequences were identified in the unique DNA stretches of the IGS by their sequence similarity to the promoter of Aedes aegypti L. (Diptera: Culicidae). The observed sequence variation can be explained, as in the case of Drosophila spp., by the occurrence of slippage‐like and point mutation processes, with unequal crossing‐over homogenizing (to a certain extent) the region throughout the gene family and blackfly population. The 18S and 28S rDNA genes show more intraspecific variability within the expansion segments than in the core regions. This is also the case in the interspecific comparison of these genes from S. sanctipauli with those of Simulium vittatum, Ae. albopictus and D. melanogaster. This pattern is typical of many eukaryotes and likely to be the result of a more relaxed functional selection in the expansion segments than on the core regions. The A + T content of the S. sanctipauli genes is high and similar to those of other Diptera. This could be the result of a change in the mutation pressure towards AT in the Diptera lineage.
Insecticide‐treated plastic tarpaulins for control of malaria vectors in refugee camps
Authors: Graham K. , Mohammad N. , Rehman H. , Nazari A. , Ahmad M. , Kamal M. , Skovmand O. , Guillet P. , Allan R. , Zaim M. , Yates A. , Lines J. , Rowland M.
Published: March 2003

Abstract Spraying of canvas tents with residual pyrethroid insecticide is an established method of malaria vector control in tented refugee camps. In recent years, plastic sheeting (polythene tarpaulins) has replaced canvas as the utilitarian shelter material for displaced populations in complex emergencies. Advances in technology enable polythene sheeting to be impregnated with pyrethroid during manufacture. The efficacy of such material against mosquitoes when erected as shelters under typical refugee camp conditions is unknown. Tests were undertaken with free‐flying mosquitoes on entomological study platforms in an Afghan refugee camp to compare the insecticidal efficacy of plastic tarpaulin sprayed with deltamethrin on its inner surface (target dose 30 mg/m2), tarpaulin impregnated with deltamethrin (initially ≥ 30 mg/m2) during manufacture, and a tent made from the factory impregnated tarpaulin material. Preliminary tests done in the laboratory with Anopheles stephensi Liston (Diptera: Culicidae) showed that 1‐min exposure to factory‐impregnated tarpaulins would give 100% mortality even after outdoor weathering in a temperate climate for 12 weeks. Outdoor platform tests with the erected materials (baited with human subjects) produced mosquito mortality rates between 86–100% for sprayed or factory‐impregnated tarpaulins and tents (average ˜40 anophelines and ˜200 culicines/per platform/night), whereas control mortality (with untreated tarpaulin) was no more than 5%. Fewer than 20% of mosquitoes blood‐fed on human subjects under either insecticide‐treated or non‐treated shelters. The tarpaulin shelter was a poor barrier to host‐seeking mosquitoes and treatment with insecticide did not reduce the proportion blood‐feeding. Even so, the deployment of insecticide‐impregnated tarpaulins in refugee camps, if used by the majority of refugees, has the potential to control malaria by killing high proportions of mosquitoes and so reducing the average life expectancy of vectors (greatly reducing vectorial capacity), rather than by directly protecting refugees from mosquito bites. Mass coverage with deltamethrin‐sprayed or impregnated tarpaulins or tents has strong potential for preventing malaria in displaced populations affected by conflict.
`When the talking starts': a framework for analysing tutorials
Authors: Thomas  , Snadden  , Carlisle
Published: March 2003

The drive towards learner‐centred learning which will equip doctors for the next century has encouraged the exploration of alternative ways of learning. A fundamental assumption is that a new learning strategy will either fit into existing patterns or trigger changes in the way that teachers and learners talk together. Despite the use of videotaped tutorials within re‐accreditation visits in parts of the UK, the literature reveals no currently existing frameworks to analyse these teaching/learning interactions in the general practice setting. In this qualitative study of tutorials in general practice vocational training, a new grounded theory was developed. This study was innovative in its use of audiotaped tutorials as opposed to espoused theories of interaction. The new theoretical framework of Trainer/GP Registrar interactions consists of five categories: `gaps to be filled', `listening in', `quick fix', `problem solving' and `talk on'. Each category illustrates whose agenda was met, who triggers the learning issue, time factors, the educational philosophy and the degree of reflection encouraged. The key principle underpinning this framework is that for learning to be effective a range of educational transactions may need to occur. If educational transactions occur exclusively around one point on the framework, the quality of training and opportunities for critical reflection may suffer. This framework may have implications for the analysis by Trainers of their teaching dialogues in the same way that consultation analysis has informed the development of consultation styles in general practice.
Working patterns and the quality of training of medical house officers: evaluating the effect of the `new deal'
Authors: Kapur Navneet , House Allan
Published: March 2003

The `new deal' on junior doctors' hours of work has led to the widespread introduction of working patterns such as full shifts and partial shifts in the United Kingdom. The impact of these changes on the training of medical staff is unclear. The subjects of the current study were 36 pre‐registration medical house officers working shift rotas and on‐call rotas at a teaching hospital in the north of England. They were studied over a 12‐month period using a self‐report questionnaire seeking their views on the quality of their training experience and their satisfaction with the in‐service training they received. Nursing staff, consultant and medical student opinion was also sought. Partial‐shift and full‐shift systems led to reduced hours of work when compared to on‐call rotas (mean hours: partial shift 65·0; full shift 59·8; on‐call 72·7), but they were associated with significantly lower training experience and training satisfaction scores for the house officers than were on‐call systems (P < 0·01). Shift systems were unpopular among consultants and medical students but not nursing staff. Despite reducing excessive hours of work, shifts may be detrimental to the training of medical house officers. The further imposition of shift working should be suspended until such time as the impact of new working patterns on the training of medical staff has been determined.
Faculty evaluation in Departments of Family Medicine: do our universities measure up?
Authors: Green Michael E , Ellis Connie L , Frémont Pierre , Batty Helen
Published: March 2003

Family medicine programmes at Canadian universities have expanded dramatically over the past several years. The development of effective means of faculty evaluation is a real concern for these departments as they strive to maintain the high quality of their teaching programmes in the face of rapid change. The literature on faculty evaluation, including reviews and articles discussing the application of faculty evaluations, is reviewed. The current state of faculty evaluation at three Canadian family medicine departments has also been surveyed. Student evaluations were found to be valid, accurate and well studied. They are not perfect, however, and require the use of additional methods such as peer review or video review in conjunction in order to provide a comprehensive evaluation of all areas of faculty activity. Faculty evaluation in family medicine teaching units and community‐based settings has not been well studied. Our survey of faculty evaluation at three Canadian universities shows much room for improvement, particularly in community‐based settings where evaluation is almost non‐existent. Expanding the use of faculty evaluations for formative means and linking evaluation to faculty development opportunities are essential if improvements to the currently used systems are to be successful and accepted by faculty. Special consideration must be given to community‐based settings where systems designed for use in larger university settings will need to be modified substantially before they can be used effectively. Further research is required in this area.
Attitudes to recertification measured over time using a validated semantic differential scale
Authors: Tracey  , Arroll  , Richmond
Published: March 2003

Objectives

This study was designed to measure the acceptability of the Royal New Zealand College of GPs' Recertification programme to the GPs in the programme.

Design

Questionaire study of a stratified random sample of members of the RNZCGP.

Method

A semantic differential attitude scale was developed and validated. The scale was administered to 300 GPs before the Recertification programme began and repeated with 100 of these GPs 18 months later. After 3 years of the programme the questionnaire was administered to the original 300 GPs.

Results

Baseline data showed reasonable acceptance of the concept of recertification but by 18 months there was a significant deterioration in the way the programme was perceived and this did not change over 3 years. Many GPs were not convinced of the value of the programme.
The performance of foreign medical graduates on the National Board of Medical Examiners (NBME) standardized patient examination prototype: a collaborative study of the NBME and the educational Commission for Foreign Medical Graduates (ECFMG)
Authors: Ben‐David  , Klass  , Boulet  , Champlain  , King  , Pohl  , Gary
Published: March 2003

Objectives

The purpose of the study was to explore foreign medical graduates’ (FMGs) performance on a clinical skills (SPX) examination. The National Board of Medical Examiners (NBME) is in the process of developing an SPX for potential use in the United States Medical Licensing Examination (USMLE). The Educational Commission for Foreign Medical Graduates (ECFMG) is developing the Clinical Skills Assessment (CSA) as an additional requirement for FMGs who wish to be certified by ECFMG.

Design

Thirty‐three FMGs and 151 United States medical students (USMSs) took the SPX during the winter of 1996 as part of the ongoing pilot studies conducted by the NBME. Four clinical skill areas were assessed: history‐taking, physical examination, communication and interpersonal skills. The examination used in this research consisted of 12 cases. The examination utilizes standardized patients (SPs) who are trained to document examinee behaviours and evaluate the communication component of the test. The SPs were also trained to evaluate the English proficiency of the candidates. Candidates were also administered the Test of Spoken English developed by the Educational Testing Services (ETS).

Setting

The examination was conducted in one medical school which served as an SPX centre for NBME pilot studies.

Subjects

Thirty‐three foreign medical students and 151 US medical students.

Results

The indications were that the majority of candidates in both groups felt the examination was moderately fair but 78% of FMGs felt moderately pressed for time, vs. 80% of the USMSs who did not feel pressed for time. Reliabilities obtained for the various SPX components were somewhat higher for the FMGs reflecting the heterogeneity of this group.

Conclusions

The NBME–ECFMG collaborative study yielded important information regarding the NBME SPX prototype as a performance measure for FMGs.
Comparative phylogeography and postglacial colonization routes in Europe
Authors: TABERLET PIERRE , FUMAGALLI LUCA , WUST‐SAUCY ANNE‐GABRIELLE , COSSON JEAN‐FRANÇOIS
Published: March 2003

The Quaternary cold periods in Europe are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in both animals and plants. The phylogeographies of 10 taxa, including mammals (Ursus arctos, Sorex spp., Crocidura suaveolens, Arvicola spp.), amphibians (Triturus spp.), arthropods (Chorthippus parallelus), and plants (Abies alba, Picea abies, Fagus sylvatica, Quercus spp.), were analysed to elucidate general trends across Europe. Only a small degree of congruence was found amongst the phylogeographies of the 10 taxa, but the likely postglacial colonization routes exhibit some similarities. A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier. The comparison of colonization routes highlighted four main suture‐zones where lineages from the different refugia meet. Some of the intraspecific genetic distances among lineages indicated a prequaternary divergence that cannot be connected to any particular cold period, but are probably related mainly to the date of arrival of each taxon in the European continent. As a consequence, molecular genetics so far appears to be of limited use in dating Quaternary events.
Genetic variation, its assessment and implications to the conservation of seagrasses
Authors: WAYCOTT MICHELLE
Published: March 2003

In a study of the widespread Australian endemic seagrass Posidonia australis, allozyme analysis identified a wide range in population genetic structure assessed using the multilocus genotype diversity statistic (DG). Values of DG between zero and one were obtained; however, RAPD analysis generally detected higher levels of diversity, where DG values were all greater than 0.5 (DG = 0.67 – 1). Some populations were allozymically monomorphic using allozyme analysis yet were highly polymorphic using RAPD analysis. The differences observed between methods, particularly among allozymically uniform populations, demonstrate the importance of choosing an appropriate method when assessing genotypic diversity. Different methods may reflect different historical aspects of population processes where allozymes reflect broader‐scale gene flow and population establishment and DNA fingerprinting methods such as RAPDs may reflect fine‐scale local recruitment events and shorter‐term population processes. Using either method alone, particularly in genotypically depauperate organisms such as seagrasses and other clonal organisms, will be problematic in assessing their population genetic potential, a parameter being used by conservation managers to decide upon management strategies in rare and endangered organisms. It is recommended that the impact of disturbance assessed using genotypic diversity measures requires more than one technique to provide the most appropriate information for designing subsequent conservation strategies.
Phylogeography of skinks (Chalcides) in the Canary Islands inferred from mitochondrial DNA sequences
Authors: BROWN R. P. , PESTANO J.
Published: March 2003

Mitochondrial DNA (mtDNA) evolution was investigated in skinks of the genus Chalcides found in the Canary Islands (Ch. sexlineatus, Ch. viridanus and Ch. simonyi), together with some North African congenerics (Ch. polylepis and Ch. mionecton). Several sites were included within islands to cover areas of known within‐island geographical variation in morphology. Skinks from the islands of El Hierro and La Gomera appear to be sister taxa. The relationships between this clade and the Tenerife and Gran Canarian skinks were not fully resolved, although the best working hypothesis indicated monophyly with the former, with the latter forming a closely related outgroup. Ch. simonyi from Fuerteventura was more distantly related to the Western Canary Island skinks and did not show close relationships with the North African species Ch. mionecton and Ch. polylepis. Possible colonization sequences for the four most Western Canary Islands were considered. El Hierro appears to have been colonized relatively recently from La Gomera, commensurate with the recent origin of this island, while dispersal between La Gomera and Tenerife and between Gran Canaria and Tenerife or La Gomera appears to have taken place considerably earlier. Substantial within‐island haplotype divergence was found in Gran Canaria and Tenerife. This may be a result of recent periods of intense volcanic activity found within these two islands. Lower levels of within‐island differentiation are found in La Gomera and El Hierro and may be explained by lower levels of volcanic activity during recent geological history and a more recent colonization, respectively.
Analysis of gene inheritance and expression in hybrids between transgenic sugar beet and wild beets
Authors: DIETZ‐PFEILSTETTER A. , KIRCHNER M.
Published: March 2003

Reciprocal gene exchange between cultivated sugar beet and wild beets in seed production areas is probably the reason for the occurence of weed beets in sugar beet production fields. Therefore, when releasing transgenic sugar beet plants into the environment, gene transfer to wild beets (Beta vulgaris ssp. maritima) has to be considered. In this study the transfer of BNYVV‐ (beet necrotic yellow vein virus) resistance and herbicide‐tolerance genes from two transgenic sugar beet lines that were released in field experiments in 1993 and 1994 in Germany to different wild beet accessions was investigated. In order to evaluate the consequences of outcrossing, manual pollinations of emasculated wild beet plants with homozygous transgenic sugar beet plants were performed. In the resulting hybrids the transgenes were stably inherited according to Mendelian law. Gene expression in leaves and roots of the hybrids was in the same range as in the original transgenic sugar beet plants. Moreover, it was found that in one of the wild beet accessions, transfer and expression of the BNYVV resistance gene did considerably increase the level of virus resistance.
Genetic evidence for a recent origin by hybridization of red wolves
Authors: Reich D. E. , Wayne R. K. , Goldstein D. B.
Published: March 2003

Genetic data suggest that red wolves (Canis rufus) resulted from a hybridization between coyotes (C. latrans) and grey wolves (C. lupus). The date of the hybridization, however, is uncertain. According to one hypothesis, the two species came into contact as coyotes increased their geographical range in conjunction with the advance of European settlers and as grey wolves were extirpated from the American south. Alternatively, the red wolves could have originated tens of thousands of years ago as a result of climate and habitat changes that disturbed the ecology of the two parent species. To obtain an upper limit on the date of hybridization that would help to distinguish the two scenarios, we compared microsatellite allele length distributions from red wolves, coyotes and grey wolves. Subject to the assumptions of our analysis, we conclude that the red wolves originated as a result of hybridizations that occurred during the past 12 800 years, and probably during the past 2500 years.
Genetic variation, population structure and cryptic species within the black mudfish, Neochanna diversus, an endemic galaxiid from New Zealand
Authors: Gleeson D. M. , Howitt R. L. J. , Ling N.
Published: March 2003

To investigate the phylogenetic relationships and geographical structure among landlocked populations of the black mudfish, Neochanna diversus, mitochondrial DNA nucleotide sequence data were sampled from seven populations from the Waikato and Northland regions of New Zealand. The complete D‐loop region was sequenced from 70 individuals, with 913 bp from the tRNA‐pro end used in population and phylogenetic analysis. A tandem repeat array, which ranged in size up to 200 bp, was found in most populations at the 3′ end of the D‐loop that was not able to be aligned for analysis. Of the seven sites sampled, two from Northland exhibited significant sequence divergence from all other sites. There was also a clear distinction among remaining Northland sites and those from the Waikato. An additional 518 bp segment of the 16S region was sequenced from all sites and compared with the other New Zealand mudfish species, N. apoda, N. burrowsius and the Tasmanian mudfish Galaxias (Neochanna) cleaveri using Galaxias maculatus as an outgroup. Both D‐loop and 16S sequence data provided strong evidence for a cryptic species of mudfish present in Northland. The significant genetic structure apparent in the black mudfish appears most probably to be attributed to geological conditions during the Pliocene, where peat wetlands became apparent in the Waikato while Northland consisted of disjunct ‘islands’. Conservation and management of these populations must take into account the historical processes that have shaped these patterns of genetic diversity.
Complete exclusion of nonsires in an analysis of paternity in a natural plant population using amplified fragment length polymorphism (AFLP)
Authors: KRAUSS SIEGFRIED L.
Published: March 2003

The utility of the new polymerase chain reaction (PCR)‐based multilocus DNA fingerprinting technique amplified fragment length polymorphism (AFLP) for paternity analysis in natural plant populations was assessed. In a natural population of 25 plants of Persoonia mollis (Proteaceae), three AFLP primer pairs generated 147 dominant loci. Of these, 125 (85%) were polymorphic, with a mean recessive allele frequency of 0.735. The theoretical expected percentage of offspring for which all males except the true father can be excluded (PET) was 99.9% for this population. The estimates of PET drop marginally to 99.6% and 97.6% for larger populations of 100 and 1000 individuals, respectively. A preliminary investigation confirmed the power of AFLP for paternity analysis by assigning paternity, or excluding all known potential sires, for 242 of 252 (96.0%) naturally pollinated seeds. Ambiguous paternity for the remaining 10 seeds was quickly resolved by utilizing two further AFLP primer pairs, ultimately generating over 200 polymorphic loci and resulting in the exclusion of all nonsires for all 252 (100%) seeds. This study highlights the utility of AFLP for paternity analysis because: (i) it generates sufficiently large numbers of highly reproducible polymorphic loci, that are (ii) quickly and accurately scored using an automated DNA sequencer and dedicated software, and (iii) unlike microsatellites, requires no sequence knowledge so it is more easily applied to new study species.
Reticulated and epidemic population genetic structure of Rhizobium etli biovar phaseoli in a traditionally managed locality in Mexico
Authors: SILVA C. , EGUIARTE L. E. , SOUZA V.
Published: March 2003

We conducted a multilocus enzyme electrophoresis (MLEE) study to assess the genetic structure of the nitrogen‐fixing bacteria Rhizobium etli bv. phaseoli. We analysed the genetic variation at 10 enzyme‐encoding chromosomal loci of 482 isolates from root nodules of Phaseolus vulgaris and P. coccineus bean plants. The isolates were obtained from six traditionally managed agricultural plots in two localities in the State of Puebla, in Central Mexico. The total mean genetic diversity (HE) for the six plots was 0.531. Among the 482 isolates collected, 126 distinctive multilocus genotypes (electrophoretic types [Ets]) were obtained, and approximately half of the isolates are represented by five widespread ETs. A significant degree of genetic differentiation among the six plots (GST = 0.072) and between the two localities (GST = 0.022) was detected. The main part of the observed variability (70%) was found among the isolates within the plants. The cluster analysis revealed two deeply diverging lineages, separated at a genetic distance of 0.7. When a multilocus linkage disequilibrium analysis was performed at different hierarchical levels, we found significant linkage disequilibrium, but when the analysis was performed for the genotypes within the two diverging lineages, we found evidence of recombination. We propose for R. etli bv. phaseoli a reticulated and epidemic genetic structure, in which few genotypes increase in frequency to produce numerically dominant clones, and genetic exchange occurs mainly among genotypes within each lineage.
Multiple paternity in social Hymenoptera: estimating the effective mate number in single–double mating populations
Authors: Pedersen J. S. , Boomsma J. J.
Published: March 2003

Several hypotheses have been advanced to explain the widespread occurrence of multiple mating by queens in eusocial bees, wasps and ants. In order to test competing hypotheses, it is essential to obtain an accurate description of the distribution of mate number and the mates’ respective contributions to the brood in populations under study. In this study we examine current methods for estimating the effective mate number and other paternity frequency parameters in populations dominated by single and double mating of queens, based on genetical data from parent–offspring combinations. Estimation errors are due to limited sample size of offspring (nonsampling error) and limited variation of genetic markers (nondetection error). We demonstrate that limited sample size of offspring leads to an underestimation of the paternity contribution from the majority male of double‐mated queens (the paternity skew or sperm bias), thus overestimating the effectiveness of double matings and underestimating the population frequency of double‐mated queens. We propose a calculation procedure which avoids this bias. Furthermore, we propose a general method to correct simultaneously for errors from nondetection and nonsampling when estimating the population frequency of double‐mated queens. The calculation procedures presented are designed for male‐haplodiploid social Hymenoptera but some can be applied directly to studies of diplo‐diploid mating systems where single and double mating prevail. This has particular relevance to vertebrate studies where the number of offspring studied per mother is invariably low. The remaining calculation procedures are conceptually widely applicable, but details would have to be modified for other than haplodiploid mating systems.
Population boundaries and genetic diversity in the endangered Mariana crow (Corvus kubaryi)
Authors: Tarr C. L. , Fleischer R. C.
Published: March 2003

The Mariana crow (Corvus kubaryi) is an endangered species that is restricted to the islands of Guam and Rota in the Mariana archipelago. Predation by the introduced brown tree snake (Boiga irregularis) has decimated bird populations on Guam, and the crow population there is the last wild remnant of the endemic forest avifauna. The population on Guam is critically endangered and, despite intensive management, the population has continued to decline. Additional management options include intermixing the Guam and Rota populations, but such options are best evaluated within a population genetics framework. We used three types of molecular markers to assay genetic variation in the Mariana crow: mitochondrial DNA (mtDNA) sequences, minisatellites and microsatellites. The two populations could be differentiated by mtDNA sequencing and they differed in allele frequencies at nuclear markers. Thus, the populations could be designated as evolutionarily significant units. However, the Guam population is genetically more diverse than the Rota population, and its survival probability if managed separately is very low. All markers did indicate that the two populations are closely related and separated by a shallow genealogical division. Intermixing the populations is justified by two rationales. First, the apparent population differences may result from recent human activities. Second, a greater amount of genetic information may be preserved by joint management. The translocation of birds from Rota to Guam has begun, but strategies that will ensure maintenance of the variation in the Guam population warrant further exploration.
Extensive intraspecific chloroplast DNA (cpDNA) variation in the alpine Draba aizoides L. (Brassicaceae): haplotype relationships and population structure
Authors: Widmer A. , Baltisberger M.
Published: March 2003

Chloroplast DNA (cpDNA) sequence variation is currently the most widely used tool for the inference of phylogenetic relationships among plants at all taxonomic levels. Generally, noncoding regions tend to evolve faster than coding sequences and have recently been applied to the study of phylogenetic relationships among closely related taxa. An implicit assumption of many of these studies is that intraspecific cpDNA variation is either absent or low and therefore will not interfere with the reconstruction of interspecific relationships. A survey of cpDNA sequence variation in the common alpine plant species Draba aizoides L. was undertaken to assess levels of intraspecific cpDNA sequence variation. These levels were compared to levels of interspecific sequence divergence between D. aizoides and related alpine Draba species. Intraspecific cpDNA sequence divergence was extensive in D. aizoides, and intraspecific differences were often larger than interspecific differences. cpDNA haplotype relationships were explored using a maximum parsimony approach and minimum‐spanning networks. Results from both methods were largely congruent but comparisons provided interesting insights into the presumed evolutionary history of cpDNA haplotypes. A combined effect of cpDNA introgression and complex lineage sorting was inferred to explain the pattern of cpDNA variation found in D. aizoides. Our results suggest that intraspecific cpDNA variation can be extensive and that intraspecific variation needs to be taken into account when inferring phylogenetic relationships among closely related taxa.
High genome‐wide mutation rates in vegetatively propagated bermudagrass
Authors: Caetano‐anollés G.
Published: March 2003

A cascade DNA amplification strategy that generates arbitrary signatures from amplification profiles (ASAP) was used to measure genome‐wide mutation rates in bermudagrass (Cynodon). ASAP quantified nucleotide changes that were induced by irradiation, genetic instabilities and normal vegetative growth of cultivars and accessions of sterile interspecific hybrids. DNA sequence divergence between cultivar ‘Tifway’ and its γ radiation‐induced mutant ‘Tifway II’ (0.70 ± 0.66%) was comparable to estimates in radiation‐induced mutants and spontaneous sports of chrysanthemum (Chrysanthemum morifolium Ramat.). A similar divergence in sequence (0.95 ± 0.20%) was observed in the pairwise comparison of 17 nondisjunctive ‘Tifgreen’ and ‘Tifdwarf’ accessions. Mutation during normal Tifdwarf vegetative growth was evaluated by planting sprigs and sampling their offspring. Somatic sequence divergence levels (0.004 ± 0.007%) resulted in a mutation rate of 1.05 × 10−8 per nucleotide per generation, assuming that a bermudagrass sprig constitutes a generation of growth. These rates were comparable to those found in germinal cells and individuals of either human or Drosophila melanogaster, supporting the notion that eukaryotic evolution is generation rather than time dependent. The high accumulation of somatic mutations (10 per triploid genome) is consistent with a model whereby mutation load in a population exhibiting obligate vegetative reproduction is substantially higher than in a population under sexual or asexual reproduction. These constraints could be the cause of reported genetic instabilities in the Tifgreen–Tifdwarf complex. Finally, a long‐term rate measured across accessions and indicative of the accumulation of mutations in 17 Tifgreen–Tifdwarf populations (µ = 1.02 × 10−8 per nucleotide per generation) was strikingly congruent with the bermudagrass vegetative mutation rate, suggesting absence of evolutionary constraints in the sampled genomic regions. Mutation rates calculated from across‐accesions divergence estimates (5.18 ± 0.53%) indicated that plant material was evolving 100 times faster (3.8 × 10−7 changes per nucleotide per year) than a molecular clock rate estimate for grasses, probably resulting from the compound effect of clonal growth and life span of the hybrid plant material.
Divergence in the chloroplast genome and nuclear rDNA of the rare Western Australian plantLambertia orbifoliaGardner (Proteaceae)
Authors: Byrne M. , Macdonald B. , Coates D.
Published: March 2003

The population genetic structure of the Australian plantLambertia orbifoliawas investigated for chloroplast DNA (cpDNA) and rDNA based on restriction fragment length polymorphism. Variation was assessed in 14–20 individuals from six populations with probes covering the majority of the chloroplast genome and the whole rRNA gene unit. For cpDNA, eight mutations were detected which were distributed over five haplotypes. Nucleotide diversity in the species was high and the majority of this diversity was distributed between populations with diversity within populations restricted to a single population. There was significant differentiation between the two regions in the species distribution with the Narrikup region being distinguished by a single haplotype that was characterized by six unique mutations. Variation in rDNA was detected with three gene length variants present in most individuals. However, the Narrikup region was characterized by homogenization of the gene unit to a single length variant in all individuals. The divergence of the Narrikup region suggests that the disjunction in the species distribution has been present for a long time and the two regions represent separate evolutionary lineages.
Genetic variation in an apomictic grass, Heteropogon contortus, in the Hawaiian Islands
Authors: Carino Debbie A. , Daehler Curtis C.
Published: March 2003

Random amplified polymorphic DNA (RAPD) markers were used to assess genetic variation within and among Hawaiian populations of an apomictic grass, Heterogopon contortus (pili grass). From among 56 individuals sampled from six populations on O’ahu and Hawai’i, 55 unique genotypes were detected using 33 polymorphic markers. This lack of uniformity among individuals may indicate frequent sexual reproduction in these populations. Analysis of molecular variance (amova) revealed significant variation among populations (30.2%), but higher levels of variation within populations (68.1%). Cluster analysis revealed a high degree of clustering for most populations, but populations from different islands did not cluster together. The presence of among‐population differentiation but lack of between‐island differentiation may suggest that H. contortus was an early Polynesian introduction to the Hawaiian Islands.
Genetic characterization of heather (Calluna vulgaris (L.) Hull) subject to different management regimes across Great Britain
Authors: Meikle A. , Paterson S. , Finch R. P. , Marshall G. , Waterhouse A.
Published: March 2003

Heather plants were collected from 34 populations in Great Britain, which differed according to their geographical location and associated management histories. Comparisons of differential grazing regimes were made across 10 sites in the first year of study, whereas the influence of differential burning regimes was considered at four sites during the second year. The extent of genetic variation, both within and between the selected heather populations, was examined using polymerase chain reaction (PCR)‐based DNA fingerprinting methodologies. Initially, high genetic variation within populations obscured differences between populations. Heather stands that were geographically close proved to be genetically similar. Site latitude and longitude were strongly associated with genetic differences between heather populations; however, a range of grazing and burning management treatments had no consistent effect upon genetic diversity. The results represent the first national survey of genetic variation at the DNA level within UK populations of this important heathland species. They provided insights into the genetic structure of heather‐dominated heathlands, revealing a lack of clonal dominance within populations, but rather a much more varied genetic makeup than might have been expected given the species’ ability to propagate vegetatively. The processes that influence genetic diversity in heather populations are discussed, and the potential role of molecular techniques in heathland conservation is considered.
Hypothesis testing with the similarity index
Authors: Leonard A. C. , Franson S. E. , Hertzberg V. S. , Smith M. K. , Toth G. P.
Published: March 2003

Multilocus DNA fingerprinting methods have been used extensively to address genetic issues in wildlife populations. Hypotheses concerning population subdivision and differing levels of diversity can be addressed through the use of the similarity index (S), a band‐sharing coefficient, and many researchers construct hypothesis tests with S based on the work of Lynch. It is shown in the present study, through mathematical analysis and through simulations, that estimates of the variance of a mean S based on Lynch’s work are downwardly biased. An unbiased alternative is presented and mathematically justified. It is shown further, however, that even when the bias in Lynch’s estimator is corrected, the estimator is highly imprecise compared with estimates based on an alternative approach such as ‘parametric bootstrapping’ of allele frequencies. Also discussed are permutation tests and their construction given the interdependence of Ss which share individuals. A simulation illustrates how some published misuses of these tests can lead to incorrect conclusions in hypothesis testing.
Molecular evidence for multiple infections of a new subgroup ofWolbachiain the European raspberry beetleByturus tomentosus
Authors: Malloch G. , Fenton B. , Butcher R. D. J.
Published: March 2003

Wolbachia, a group of maternally inherited intracellular parasitic bacteria, alter host reproduction, including the induction of thelytokous parthenogenesis, feminization of genetic males, son killing and, most commonly, the induction of cytoplasmic incompatibility (CI), in a diverse array of arthropods. CI can result in infertility and has attracted attention because of its potential in biological control and as an agent in speciation. Although there has been some analysis of overall infection rates in arthropods and within individual insect orders, there has been little exploration of within‐species variation. In this study, primers specific for theftsZgene ofWolbachiawere used to amplify it from different geographical samples of the European raspberry beetle (Byturus tomentosus), confirming the presence ofWolbachia. More than 99% of UK individuals were found to be infected withWolbachiaand 97% of theseB. tomentosusbeetles harboured multiple infections. Preliminary analysis ofB. tomentosusbeetles from continental European populations revealed a lower level of infection (24%) than those from the UK. Phylogenetic analysis using theftsZDNA sequences placesWolbachiafromB. tomentosusinto a new clade (Abt) within the A division, with some revisions to the existingWolbachiaphylogeny.
Mitochondrial DNA sequences support allozyme evidence for cryptic radiation of New Zealand Peripatoides (Onychophora)
Authors: Trewick S. A.
Published: March 2003

A combination of single‐strand conformation polymorphism analysis (SSCP) and sequencing were used to survey cytochrome oxidase I (COI) mitochondrial DNA (mtDNA) diversity among New Zealand ovoviviparous Onychophora. Most of the sites and individuals had previously been analysed using allozyme electrophoresis. A total of 157 peripatus collected at 54 sites throughout New Zealand were screened yielding 62 different haplotypes. Comparison of 540‐bp COI sequences from Peripatoides revealed mean among‐clade genetic distances of up to 11.4% using Kimura 2‐parameter (K2P) analysis or 17.5% using general time‐reversible (GTR + I + Γ) analysis. Phylogenetic analysis revealed eight well‐supported clades that were consistent with the allozyme analysis. Five of the six cryptic peripatus species distinguished by allozymes were confirmed by mtDNA analysis. The sixth taxon appeared to be paraphyletic, but genetic and geographical evidence suggested recent speciation. Two additional taxa were evident from the mtDNA data but neither occurred within the areas surveyed using allozymes. Among the peripatus surveyed with both mtDNA and allozymes, only one clear instance of recent introgression was evident, even though several taxa occurred in sympatry. This suggests well‐developed mate recognition despite minimal morphological variation and low overall genetic diversity.
Genetic subdivision, glacial refugia and postglacial recolonization in the golden‐striped salamander, Chioglossa lusitanica (Amphibia: Urodela)
Authors: Alexandrino J. , Froufe E. , Arntzen J. W. , Ferrand N.
Published: March 2003

The golden‐striped salamander (Chioglossa lusitanica) is an ecologically specialized species, endemic to north‐western Iberia. Patterns of genetic variation were assessed at seven polymorphic enzyme loci and one mitochondrial DNA (mtDNA) marker (cytochrome b) in 17 populations across its range. Estimates of enzyme genetic diversity revealed a high degree of genetic subdivision (FST = 0.68), mainly attributable to the existence of two groups of populations. The groups were located, respectively, north and south of the Mondego River, indicating that this river coincided with a major historical barrier to gene flow. A significant decrease in genetic variability from the Mondego northwards was associated with the Douro and Minho rivers. mtDNA sequence variation revealed a congruent pattern of two haplotype groups (d = 2.2%), with a geographical distribution resembling that of allozymes. The pattern and depth of genetic variation is consistent with the following hypotheses: (i) subdivision of an ancestral range of the species prior to the middle Pleistocene; (ii) secondary contact between populations representing historical refugia; (iii) relatively recent range expansion giving rise to the northern part of the species range; and (iv) loss of genetic variation through founder effects during range expansion across major rivers.
Clonal structure in a dwarf bamboo (Sasa senanensis) population inferred from amplified fragment length polymorphism (AFLP) fingerprints
Authors: Suyama Y. , Obayashi K. , Hayashi I.
Published: March 2003

Amplified fragment length polymorphism (AFLP) fingerprints were used to reveal clonal structure of a dense population of dwarf bamboo, Sasa senanensis, in a 10‐ha study plot at Sugadaira Montane Research Center, University of Tsukuba, Nagano, Japan. We generated AFLP fingerprints for 51 leaf samples, collected at 50 m intervals, using three selective primer pairs. A total of 135–166 fragments were detected per sample, and 22 different fingerprints were identified based on 24–83 differing fragments. Our results demonstrate that the S. senanensis population in our plot consists of at least 22 clones and that the largest single clone occurs over a distance of about 300 m. Furthermore, the clone distribution pattern implies a relationship between site quality and clonal structure.