bluuebunny/crossref_metadata_2025 huggingface dataset:
Process evaluation of two environmental nutrition programmes and an educational nutrition programme conducted at supermarkets and worksite cafeterias in the Netherlands
Authors: Steenhuis I. , van Assema P. , Reubsaet A. , Kok G.
Published: December 2004

Introduction  This article describes the process evaluation of two environmental programmes and an educational nutrition programme, implemented at supermarkets and worksite cafeterias. Studies conducted earlier, indicated that the programmes had no effect on consumers’ eating behaviour. Consequently, the more specific purpose of the present study was to identify explanations for the ineffectiveness of the programmes and to formulate recommendations for future programmes.

Materials and methods  The environmental programmes included labelling of healthy products and increasing the range of healthy foods on offer. The education programme consisted of several elements, such as brochures and a self‐help guide. Semi‐structured interviews were conducted with 21 managers of supermarkets and worksite cafeterias where the programmes were implemented.

Results  Although materials were not always entirely compatible with the different supermarkets and worksite cafeterias, the degree of implementation was satisfactory. According to the managers, the programmes were not striking enough, the labelling would have been more effective if it had discriminated between different brands of a product, and the number of new products was too small compared with the total range of foods on offer.

Conclusions  The findings suggest that programmes should be promoted intensively. Furthermore, the relevant manufacturers and wholesalers supplying worksite cafeterias should be encouraged to increase their range of suitable low‐fat products. Finally, the feasibility and possible effects of brand‐specific labelling should be investigated further.
Quality of lipid‐lowering therapy in patients with ischaemic heart disease: a register‐based study in 3477 patients
Authors: Kanstrup H. , Lassen J. F. , Heickendorff L. , Lauritzen T. , Larsen M. L.
Published: December 2004

Objective.  To develop a method to evaluate routine management practices concerning lipid‐lowering treatment in patients with ischaemic heart disease (IHD) in a large geographic area.

Design.  A register‐based study linking information on IHD with cholesterol levels and prescriptions on lipid‐lowering medications by personal registration number. Plasma cholesterol levels were collected from the electronic laboratory information system (LIS), and information on IHD from the Danish National Hospital Register (LPR). The extent of treatment was evaluated by information on prescriptions on lipid‐lowering medications from the Danish National Health Service.

Setting.  Evaluates treatment in both hospitals and primary care.

Subjects.  Patients with IHD.

Results.  In total 3477 patients <75 years were identified, and 43.7% had claimed prescriptions on lipid‐lowering medications (01.01.2000–31.07.2000). In the whole population, 42% reached the goal for total cholesterol lower than 5 mmol L−1 set by European guidelines. In the 1521 patients treated with lipid‐lowering medications 55% reached the goal.

Conclusion.  By use of registers it was possible to develop a method to evaluate and monitor current treatment practice for dyslipidaemia in a large geographic area. The method makes it possible to evaluate the impact of guidelines, changes in treatment procedures and to provide feedback to physicians. The study revealed that lipid‐lowering treatment is still not sufficiently implemented in clinical practice even in patients with known IHD, and the used doses of statins are lower than those used in randomized clinical trials.
Amphoterin as an extracellular regulator of cell motility: from discovery to disease
Authors: Huttunen H. J. , Rauvala H.
Published: December 2004

Amphoterin is a ubiquitous and highly conserved protein previously considered solely as a chromatin‐associated, nuclear molecule. Amphoterin is released into the extracellular space by various cell types, and plays an important role in the regulation of cell migration, differentiation, tumorigenesis and inflammation. This paper reviews recent research on the mechanistic background underlying the biology of secreted amphoterin, with an emphasis on the role of amphoterin as an autocrine/paracrine regulator of cell migration.
HMGB1 is a potent trigger of arthritis
Authors: Andersson U. , Erlandsson‐Harris H.
Published: December 2004

Rheumatoid arthritis is a chronic inflammatory disease characterized by synovial inflammation and structural damage of joints. Although the cause of rheumatoid arthritis (RA) remains unknown, the excessive production of proinflammatory cytokines such as tumour necrosis factor (TNF) and interleukin‐1 (IL‐1) by intra‐articular macrophages occupies a critical pathogenic role in the development and progression of the disease. High mobility group box chromosomal protein 1 (HMGB1) is a recently identified mediator of interest in human and experimental arthritides. HMGB1 can either be actively secreted from macrophages or passively released from necrotic cells of all kinds. Activated macrophages and unprogrammed cell death caused by ischaemia or activated complement are all prominent features of chronic arthritis, contributing to the persistent synovial inflammation. HMGB1 is cytoplasmically and extracellularly overexpressed in inflammatory synovial tissue in human RA as well as experimental collagen‐induced arthritis. Elevated levels of HMGB1 are also present in synovial fluid samples from RA patients. Synovial tissue from rats with experimental arthritis exhibits aberrant deposition of HMGB1 preceding the onset of clinical signs of arthritis, and the expression becomes prominent after the onset of clinical disease. The synovial levels of HMGB1 are comparable with those of TNF and IL‐1β at the peak of manifest disease. HMGB1‐targeted intervention with either neutralizing antibodies or the antagonistic A box domain of HMGB1 ameliorates collagen‐induced arthritis both in mice and rats, and inhibits the local overexpression of IL‐1β in the joints. It is thus conceivable that therapeutic HMGB1 blockade may contribute to future treatment of human chronic arthritis.
Prognostic impact of different regional referral practices for interventional investigation and coronary treatment after exercise testing: a population‐based 5‐year follow‐up study
Authors: Niemann T. , Labouriau R. , Sørensen H. Toft , Thorsgaard N. , Nielsen T. Toftegaard
Published: December 2004

Objective. To examine the association among different centres’ referral practices for coronary angiography (CAG) after exercise testing, with 1‐ and 5‐year outcomes.

Design. Observational population‐based cohort study.

Setting. All 10 hospitals and six private practising consultants in Aarhus and Ringkjoebing counties (900 000 inhabitants), Denmark.

Subjects. All patients who in 1996 had an abnormal bicycle exercise test (n = 736).

Measurements. Referral for CAG, coronary intervention, cardiovascular and all‐cause mortality, and myocardial infarction (MI).

Results. As an immediate consequence of the exercise test, 60.7% of subjects were referred for CAG. Based on the centres’ fraction of patients referred for CAG, three categories of centres were defined: low (<33%), intermediate (33–66%) and high (>66%). A low compared with a high referral fraction was associated with a similar 5‐year mortality and MI ratio [all‐cause/cardiovascular mortality rate ratio (RR) = 1.33, 95% confidence interval (CI): 0.45–3.92/RR = 0.62, 95% CI: 0.25–1.57; and MI RR = 0.92, 95% CI: 0.45–1.86]. The same was found for an intermediate compared with a high fraction (all‐cause/cardiovascular mortality RR = 0.92, 95% CI: 0.49–1.72/RR = 0.74, 95% CI: 0.42–1.33; and MI RR = 1.07, 95% CI: 0.68–1.70). Estimates were about the same after 1 year of follow‐up with no major differences among centres in mortality or MI.

Conclusions. Centres’ different referral practices for interventional investigation and treatment were not associated significantly with short‐term or long‐term mortality or MI among patients with an abnormal exercise test.
The 21‐year follow‐up of the Cardiovascular Risk in Young Finns Study: risk factor levels, secular trends and east–west difference
Authors: Juonala M. , Viikari J. S. A. , Hutri‐Kähönen N. , Pietikäinen M. , Jokinen E. , Taittonen L. , Marniemi J. , Rönnemaa T. , Raitakari O. T.
Published: December 2004

Objectives.  The Cardiovascular Risk in Young Finns Study is an on‐going multicentre study of atherosclerosis precursors in Finnish children and young adults. We have collected risk factor data in the 21‐year follow‐up performed in 2001. The aims of this analysis were to examine the levels, secular trends and east–west difference in risk factors amongst young adults.

Design.  Population based follow‐up study.

Subjects.  A total of 2283 participants aged 24–39 years in 2001 (63.5% of the original cohort).

Main outcome measures.  Levels of serum lipids, apolipoproteins, blood pressure and smoking.

Results.  The mean serum total cholesterol, low density lipoprotein cholesterol, high density lipoprotein (HDL) cholesterol and triglyceride concentrations in 24–39‐year‐old adults were 5.16, 3.27, 1.29 and 1.34 mmol L−1, respectively. Total cholesterol (5.21 vs. 5.12 mmol L−1, P = 0.046), HDL cholesterol (1.31 vs. 1.28 mmol L−1, P = 0.027), systolic blood pressure (118 vs. 115 mmHg, P < 0.0001) and diastolic blood pressure (72 vs. 70 mmHg, P < 0.0001) were higher in subjects originating from eastern Finland compared with those from western Finland. Significant secular trends between 1986 and 2001 in 24‐year‐old subjects (n = 783) included an increase in serum triglycerides and body mass index (BMI), a decrease in blood pressure and HDL cholesterol and a modest 5% decrease in total cholesterol levels.

Conclusions.  During the past 15 years, BMI and triglyceride levels have increased in young adults in Finland. At the same time, the reduction in cholesterol concentration has been slow. Consistent with persistent regional differences in cardiovascular morbidity within Finland, our data demonstrate significant differences in the levels of cardiovascular risk factors between subjects originating from eastern and western Finland.
Orthostatic hypotension and the risk of myocardial infarction in the home‐dwelling elderly
Authors: Luukinen H. , Koski K. , Laippala P. , Airaksinen K. E. J.
Published: December 2004

Objectives.  We investigated the prognostic significance of orthostatic hypotension on the risk of myocardial infarction (MI) amongst the elderly.

Design.  Prospective population‐based study. 

Setting.  Home‐dwelling population.

Subjects.  Orthostatic testing was performed between 8 a.m. and 2 p.m., irrespective of having had meals, on 792 persons, representing 82% of all home‐dwelling persons aged ≥70 years living in five municipalities around the city of Oulu.

Main outcome measures.  Occurrence of cases of MI were recorded during mean 3.58 (SD 1.09) years follow‐up period, from national mortality statistics and local hospital discharge registers.

Results.  Ninety cases of MI, of which 40 were fatal after initial hospitalization, occurred during the follow‐up period. Orthostatic diastolic blood pressure (BP) drop 1 min after standing up was associated with subsequent MI, but systolic BP reactions had no predictive value. According to the Cox regression model, the strongest predictor of the occurrence of subsequent MI was found in regard to ≥8 mmHg drop in diastolic BP 1 min after standing up; adjusted for history of MI, diabetes mellitus, chest pain, use of calcium antagonist, β‐blocker, nitrate and diuretic medication, hazard ratio of MI being 2.00 (1.11–3.59).

Conclusions.  Orthostatic testing offers a novel means to assess the risk of MI amongst elderly persons. Diastolic BP drop immediately after standing up identifies elderly subjects at a high risk of subsequent MI.
Depot‐specific differences in perilipin mRNA but not protein expression in obesity
Authors: Arvidsson E. , Blomqvist L. , Rydén M.
Published: December 2004

Background.  Perilipin (PLIN) is a lipid droplet‐associated protein, which regulates lipolysis in rodent adipocytes by modulating the access of hormone‐sensitive lipase to the lipid surface. Little is known regarding the expression and function of PLIN in man. Subcutaneous (s.c.) and omental fat tissue display marked differences in both basal and stimulated lipolysis.

Objective and subjects.  In order to assess whether this can be caused by differences in PLIN expression, we investigated the expression of PLIN mRNA and protein in s.c. and omental fat tissue samples from 16 obese women (n = 8) and men (n = 8).

Methods.  For mRNA detection a quantitative real‐time PCR was used. Protein was analysed by Western blot.

Results.  PLIN mRNA was significantly reduced in omental versus s.c. tissue (P = 0.022). In contrast, although PLIN protein levels were highly variable between the two depots when related to the reference protein β‐actin, no significant difference in PLIN protein expression was observed between the fat depots (P = 0.61). There were no gender‐specific differences in PLIN mRNA or protein.

Conclusion.  Our results suggest that post‐transcriptional mechanisms may influence PLIN protein expression and that PLIN expression per se is probably not a major factor in determining the lipolytic differences between the s.c. and omental fat depots.
Alendronate produces greater effects than raloxifene on bone density and bone turnover in postmenopausal women with low bone density: results of EFFECT (EFficacy of FOSAMAX® versus EVISTA®Comparison Trial) International1
Authors: Sambrook P. N. , Geusens P. , Ribot C. , Solimano J. A. , Ferrer‐Barriendos J. , Gaines K. , Verbruggen N. , Melton M. E.
Published: December 2004

Objectives.  Alendronate and raloxifene are antiresorptive agents with different mechanisms of action, each used to treat osteoporosis in postmenopausal women. This study was undertaken to compare the efficacy and tolerability of alendronate to raloxifene in postmenopausal women with low‐bone density.

Design.  Randomized, double‐masked, double‐dummy multicentre international study.

Setting.  Clinical trial centres in Europe, South America and Asia‐Pacific.

Subjects.  A total of 487 postmenopausal women with low bone density, based on bone mineral density (BMD) of the lumbar spine or hip (T‐score ≤−2.0).

Interventions.  Patients received either alendronate 70 mg once weekly and daily placebo identical to raloxifene or raloxifene 60 mg daily and weekly placebo identical to alendronate for 12 months.

Main outcome measures.  Evaluations included BMD of the lumbar spine and hip and markers of bone turnover at 6 and 12 months and adverse event reporting.

Results.  Alendronate demonstrated substantially greater increases in BMD than raloxifene at both lumbar spine and hip sites at 12 months. Lumbar spine BMD increased 4.8% with alendronate vs. 2.2% with raloxifene (P < 0.001). The increase in total hip BMD was 2.3% with alendronate vs. 0.8% with raloxifene (P < 0.001). Reductions in bone turnover were significantly larger with alendronate than raloxifene. Overall tolerability was similar, however, the proportion of patients reporting vasomotor events was significantly higher with raloxifene (9.5%) than with alendronate (3.7%, P = 0.010). The proportion of patients reporting gastrointestinal events was similar between groups.

Conclusion.  In postmenopausal women with low bone density, improvements in BMD and markers of bone turnover were substantially greater during treatment with alendronate compared to raloxifene.
Estimating admixture proportions with microsatellites: comparison of methods based on simulated data
Authors: Choisy M. , Franck P. , Cornuet J.‐M.
Published: December 2004

Several methods have been developed to estimate the parental contributions in the genetic pool of an admixed population. Some pair‐comparisons have been performed on real data but, to date, no systematic comparison of a large number of methods has been attempted. In this study, we performed a simulated data‐based comparison of six of the most cited methods in the literature of the last 20 years. Five of these methods use allele frequencies and differ in the statistical treatment of the data. The last one also considers the degree of molecular divergence by estimating the coalescence times. Comparisons are based on the frequency at which the method can be applied, the bias and the mean square error of the estimation, and the frequency at which the true value is within the confidence interval. Eventually, each method was applied to a real data set of variously introgressed honeybee populations. In optimal conditions (highly differentiated parental populations, recent hybridization event), all methods perform equally well. When conditions are not optimal, the methods perform differently, but no method is always better or worse than all others. Some guidelines are given for the choice of the method.
Using molecular markers with high mutation rates to obtain estimates of relative population size and to distinguish the effects of gene flow and mutation: a demonstration using data from endemic Mauritian skinks
Authors: Nichols R. A. , Freeman K. L. M.
Published: December 2004

We propose a method of analysing genetic data to obtain separate estimates of the size (Np) and migration rate (mp) for the sampled populations, without precise prior knowledge of mutation rates at each locus (µL). The effects of migration and mutation can be distinguished because high migration has the effect of reducing genetic differentiation across all loci, whereas a high mutation rate will only affect the locus in question. The method also takes account of any differences between the spectra of immigrant alleles and of new mutant alleles. If the genetic data come from a range of population sizes, and the loci have a range of mutation rates, it is possible to estimate the relative sizes of the different Np values, and likewise the mp and the µL. Microsatellite loci may also be particularly appropriate because loci with a high mutation rate can reach mutation–drift–migration equilibrium more quickly, and because the spectra of mutants arriving in a population can be particularly distinct from the immigrants. We demonstrate this principle using a microsatellite data set from Mauritian skinks. The method identifies low gene flow between a putative new species and populations of its sister species, whereas the differentiation of two other populations is attributed to small population size. These distinct interpretations were not readily apparent from conventional measures of genetic differentiation and gene diversity. When the method is evaluated using simulated data sets, it correctly distinguishes low gene flow from small population size. Loci that are not at mutation–migration–drift equilibrium can distort the parameter estimates slightly. We discuss strategies for detecting and overcoming this effect.
Population Graphs: the graph theoretic shape of genetic structure
Authors: Dyer Rodney J. , Nason John D.
Published: December 2004

Patterns of intraspecific genetic variation result from interactions among both historical and contemporary evolutionary processes. Traditionally, population geneticists have used methods such as F‐statistics, pairwise isolation by distance models, spatial autocorrelation and coalescent models to analyse this variation and to gain insight about causal evolutionary processes. Here we introduce a novel approach (Population Graphs) that focuses on the analysis of marker‐based population genetic data within a graph theoretic framework. This method can be used to estimate traditional population genetic summary statistics, but its primary focus is on characterizing the complex topology resulting from historical and contemporary genetic interactions among populations. We introduce the application of Population Graphs by examining the range‐wide population genetic structure of a Sonoran Desert cactus (Lophocereus schottii). With this data set, we evaluate hypotheses regarding historical vicariance, isolation by distance, population‐level assignment and the importance of specific populations to species‐wide genetic connectivity. We close by discussing the applicability of Population Graphs for addressing a wide range of population genetic and phylogeographical problems.
Predominance of genetic monogamy by females in a hammerhead shark, Sphyrna tiburo: implications for shark conservation
Authors: Chapman Demian D. , Prodöhl Paulo A. , Gelsleichter James , Manire Charles A. , Shivji Mahmood S.
Published: December 2004

There is growing interest in the mating systems of sharks and their relatives (Class Chondrichthyes) because these ancient fishes occupy a key position in vertebrate phylogeny and are increasingly in need of conservation due to widespread overexploitation. Based on precious few genetic and field observational studies, current speculation is that polyandrous mating strategies and multiple paternity may be common in sharks as they are in most other vertebrates. Here, we test this hypothesis by examining the genetic mating system of the bonnethead shark, Sphyrna tiburo, using microsatellite DNA profiling of 22 litters (22 mothers, 188 embryos genotyped at four polymorphic loci) obtained from multiple locations along the west coast of Florida. Contrary to expectations based on the ability of female S. tiburo to store sperm, the social nature of this species and the 100% multiple paternity observed in two other coastal shark species, over 81% of sampled bonnethead females produced litters sired by a single male (i.e. genetic monogamy). When multiple paternity occurred in S. tiburo, there was an indication of increased incidence in larger mothers with bigger litters. Our data suggest that sharks may exhibit complex genetic mating systems with a high degree of interspecific variability, and as a result some species may be more susceptible to loss of genetic variation in the face of escalating fishing pressure. Based on these findings, we suggest that knowledge of elasmobranch mating systems should be an important component of conservation and management programmes for these heavily exploited species.
Influence of volcanic activity on the population genetic structure of Hawaiian Tetragnatha spiders: fragmentation, rapid population growth and the potential for accelerated evolution
Authors: Vandergast Amy G. , Gillespie Rosemary G. , Roderick George K.
Published: December 2004

Volcanic activity on the island of Hawaii results in a cyclical pattern of habitat destruction and fragmentation by lava, followed by habitat regeneration on newly formed substrates. While this pattern has been hypothesized to promote the diversification of Hawaiian lineages, there have been few attempts to link geological processes to measurable changes in population structure. We investigated the genetic structure of three species of Hawaiian spiders in forests fragmented by a 150‐year‐old lava flow on Mauna Loa Volcano, island of Hawaii: Tetragnatha quasimodo (forest and lava flow generalist), T. anuenue and T. brevignatha (forest specialists). To estimate fragmentation effects on population subdivision in each species, we examined variation in mitochondrial and nuclear genomes (DNA sequences and allozymes, respectively). Population subdivision was higher for forest specialists than for the generalist in fragments separated by lava. Patterns of mtDNA sequence evolution also revealed that forest specialists have undergone rapid expansion, while the generalist has experienced more gradual population growth. Results confirm that patterns of neutral genetic variation reflect patterns of volcanic activity in some Tetragnatha species. Our study further suggests that population subdivision and expansion can occur across small spatial and temporal scales, which may facilitate the rapid spread of new character states, leading to speciation as hypothesized by H. L. Carson 30 years ago.
Spatio‐temporal variation in the genetic composition of wild populations of pearl oyster (Pinctada margaritifera cumingii) in French Polynesia following 10 years of juvenile translocation
Authors: Arnaud‐Haond S. , Vonau V. , Bonhomme F. , Boudry P. , Blanc F. , Prou J. , Seaman T. , Goyard E.
Published: December 2004

The genetic impact of the cultural practice of spat collection and translocation between genetically distinct stocks of black‐lipped pearl oyster, Pinctada margaritifera cumingii, was studied by comparing samples collected in the 1980s and 2000s from seven atolls in French Polynesia. An amova revealed homogenization of the previously genetically distinct wild stocks of Tuamotu‐Gambier and Society archipelagos (the indices of genetic differentiation among archipelagos and among populations within archipelagos, respectively, ΦCT and ΦST, decreased from 0.032* and 0.025*, respectively, to 0.006NS and 0.007NS). These results suggest high success of spontaneous reproduction in farms, probably due to the very high density of cultivated pearl oysters, and underline the importance of genetic monitoring of future hatchery produced stocks.
Limited phylogeographical structure across Eurasia in two red wood ant speciesFormica pratensisandF. lugubris(Hymenoptera, Formicidae)
Authors: Goropashnaya A. V. , Fedorov V. B. , Seifert B. , Pamilo P.
Published: December 2004

The phylogeography and demographic history of two closely related species of the red wood ant (Formica pratensisandF. lugubris) were examined across Eurasia. The phylogeny based on a 1.5‐kilobase mitochondrial DNA fragment, including the cytochromebgene and part of the ND6 gene, showed one phylogeographical division inF. pratensis.This division (0.7% of nucleotide divergence) suggests postglacial colonization of western Europe and of a wide area ranging from Sweden on the west to Lake Baikal on the east from separate forest refugia. In two localities, mitochondrial DNA has been transferred fromF. lugubristoF. pratensisand all the individuals ofF. pratensissampled from the Pyrenees had haplotypes clustering in thelugubrisclade. No phylogeographical divisions were detected inF. lugubris. Comparison of species‐wide phylogeography between the two sympatrically distributed species of ant demonstrates a difference in phylogeographical structure that implies different vicariant histories. However, over most of the species’ distribution ranges, similar signs of demographic expansion predating the last glaciation and the lack of phylogeographical structure were found in both the eastern phylogroup ofF. pratensisandF. lugubris.This finding is highly consistent with the results reported for all other boreal forest animal species studied to date in Eurasia. Contraction of the distribution range of each species to a single refugial area at different times during the late Pleistocene and a subsequent population expansion seem to be an explanation for the lack of phylogeographical structure across most of Eurasia in species that are ecologically associated with the boreal forest.
Population structure and phylogeography ofSolanum pimpinellifoliuminferred from a nuclear gene
Authors: Caicedo Ana Lucía , Schaal Barbara A.
Published: December 2004

Phylogeographical studies are emerging as a powerful tool for understanding the population structure and evolution of wild relatives of crop species. Because of their value as genetic resources, there is great interest in exploring the distribution of variation in wild relatives of cultivated plants. In this study, we use sequence variation from the nuclear gene, fruit vacuolar invertase (Vac), to investigate the population history ofSolanum pimpinellifolium.Solanum pimpinellifoliumis a close relative of the cultivated tomato and has repeatedly served as a source of valuable traits for crop improvement. We sequenced the second intron of theVacgene in 129 individuals, representing 16 populations from the northern half of Peru. Patterns of haplotype sharing among populations indicate that there is isolation by distance. However, there is no congruence between the geographical distribution of haplotypes and their genealogical relationships. Levels of outcrossing decrease towards the southernmost populations, as previously observed in an allozyme study. The geographical pattern ofVacvariation supports a centre of origin in northern Peru forS. pimpinellifoliumand a gradual colonization along the Pacific coast. This implies that inbreeding populations are derived from outcrossing ones and that variation present at theVaclocus predates the spread ofS. pimpinellifolium. The expansion of cities and human agricultural activity in the habitat ofS. pimpinellifoliumcurrently pose a threat to the species.
Genetic structure of nest aggregations and drone congregations of the southeast Asian stingless beeTrigona collina
Authors: CAMERON E. C. , FRANCK P. , OLDROYD B. P.
Published: December 2004

In stingless bees, sex is determined by a single complementary sex‐determining locus. This method of sex determination imposes a severe cost of inbreeding because an egg fertilized by sperm carrying the same sex allele as the egg results in a sterile diploid male. To explore how reproductive strategies may be used to avoid inbreeding in stingless bees, we studied the genetic structure of a population of 27 colonies and three drone congregations ofTrigona collinain Chanthaburi, Thailand. The colonies were distributed across six nest aggregations, each aggregation located in the base of a different fig tree. Genetic analysis at eight microsatellite loci showed that colonies within aggregations were not related. Samples taken from three drone congregations showed that the males were drawn from a large number of colonies (estimated to be 132 different colonies in our largest swarm). No drone had a genotype indicating that it could have originated from the colony that it was directly outside. Combined, these results suggest that movements of drones and possibly movements of reproductive swarms among colony aggregations provide two mechanisms of inbreeding avoidance.
Phylogeography of a parasitoid wasp (Diaeretiella rapae): no evidence of host‐associated lineages
Authors: BAER C. F. , TRIPP D. W. , BJORKSTEN T. A. , ANTOLIN M. F.
Published: December 2004

The exceptional diversity of insects is often attributed to the effects of specialized relationships between insects and their hosts. Parasite–host interactions are influenced by current natural selection and dispersal, in addition to historical effects that may include past selection, vicariance, and random genetic drift. Both current and historical events can lead to reduced fitness on some hosts. If trade‐offs in fitness on alternate hosts are common, adaptation to one host can prevent adaptation to another, giving rise to genetic differentiation among host‐associated lineages. Previous studies ofDiaeretiella rapae(Hymenoptera: Aphidiidae), a parasitoid of aphids, have revealed additive genetic differences in performance between populations that parasitize different aphid host species. To determine whetherD. rapaepopulations collected from different aphid hosts have diverged into genetically independent lineages, we constructed a haplotype network based on sequence variation in mitochondrial DNA (mtDNA). We used single strand conformation polymorphism (SSCP) analysis to examine 2041 base pairs of mtDNA and to identify nucleotide sequences of 42 unique SSCP haplotypes. We found no association between mtDNA haplotypes and host species in either the ancestral range (Europe, Mediterranean region, Middle East, Asia) or part of the introduced range (western North America). Haplotypes likely to be ancestral were geographically widespread and found on both hosts, suggesting that the ability to use both hosts evolved prior to the diversification of the mtDNA. Ongoing gene flow appears to prevent the formation of host races.
Clonal structure and flowering traits of a bamboo [Phyllostachys pubescens(Mazel) Ohwi] stand grown from a simultaneous flowering as revealed by AFLP analysis
Authors: Isagi Y. , Shimada K. , Kushima H. , Tanaka N. , Nagao A. , Ishikawa T. , OnoDera H. , Watanabe S.
Published: December 2004

Although many bamboo species are characterized by simultaneous flowering at long intervals of up to 120 years, few studies have revealed the length of the flowering interval for very‐long‐lived bamboo species by observing the whole life cycle of a single clone. The flowering interval ofPhyllostachys pubescenshad been determined to be 67 years by means of observation through the entire life cycle from 1912 to 1979. We observed and analysed the clonal structure and flowering traits of aP. pubescenscommunity which had regenerated from seed in 1930 and began to flower in 1997. Although this interval was again 67 years, flowering and nonflowering culms were mixed, and the flowering event lasted three years in the community. AFLP analysis of DNA samples showed distinct genets that originated from the previous flowering event and that each genet had its own flowering time. This is the first report to show that (i) different genets are mixed in a community of a large bamboo species with a leptomorphic rhizome system, and (ii) a community that originated from a single flowering event can have a range of flowering years.
Differential population structuring of two closely related fish species, the mackerel (Scomber scombrus) and the chub mackerel (Scomber japonicus), in the Mediterranean Sea
Authors: ZARDOYA R. , CASTILHO R. , GRANDE C. , FAVRE‐KREY L. , CAETANO S. , MARCATO S. , KREY G. , PATARNELLO T.
Published: December 2004

Population genetic structures of the mackerel (Scomber scombrus) and chub mackerel (Scomber japonicus) were studied in the Mediterranean Sea. Fragments of 272 bp (S. scomber) and 387 bp (S. japonicus) of the 5′‐end of the mitochondrial control region were sequenced from spawning individuals collected off the coasts of Greece, Italy, Spain, and Portugal. High levels of mitochondrial control region haplotypic diversity (> 0.98) were found for both Scomber species. Nucleotide diversity was higher in the mackerel (0.022) than in the chub mackerel (0.017). Global FST values were also higher and significant in the mackerel (0.024, P < 0.0001) as opposed to the chub mackerel (0.003, P > 0.05). Molecular variance analyses showed differential genetic structuring for these two closely related species. There is extensive gene flow between Mediterranean Sea and Atlantic Ocean populations of chub mackerel, which are organized into a larger panmictic unit. In contrast, Mediterranean Sea populations of mackerel show some degree of genetic differentiation and are structured along an east–west axis. The analysed eastern Mediterranean Sea mackerel populations (Greece, Italy) are clearly separated from that of the western Mediterranean Sea (Barcelona), which forms a panmictic unit with eastern Atlantic Ocean populations. The genetic structures of both species showed asymmetric migration patterns and indicated population expansion.
Population biology of the invasive freshwater snail Physa acuta approached through genetic markers, ecological characterization and demography
Authors: BOUSSET L. , HENRY P‐Y. , SOURROUILLE P. , JARNE P.
Published: December 2004

The respective role of factors acting on population functioning can be inferred from a variety of approaches, including population genetics and demography. We here investigated the role of four of these factors (mating systems, population size, bottlenecks and migration) in the hermaphroditic freshwater snail Physa acuta. Twenty‐four populations were sampled either around Montpellier (local scale), or at the scale of France (global scale). At local scale, eight populations were sampled twice, before and after summer drying out. The genetic structure of these populations was studied using microsatellite loci. Populations were classified according to openness (ponds vs. rivers) and water regime (permanent vs. temporary) allowing predictions on genetic patterns (e.g. diversity within populations and differentiation). At local scale, progeny‐arrays analysis of the selfing rate was conducted, and size distributions of individuals were followed over two years. Results with regard to the four factors mentioned above were: (i) Estimates of population selfing rates derived from inbreeding coefficients were only slightly higher than those from progeny‐arrays. (ii) More variation was detected in rivers than in ponds, but no influence of water regime was detected. One reason might be that permanent populations are not going less often through low densities than those from temporary habitats at the time scale studied. (iii) There was limited evidence for genetic bottlenecks which is compatible with the fact that even marked reduction in water availability was not necessarily associated with demographic bottlenecks. More generally, bottlenecks reducing genetic variation probably occur at population foundation. (iv) Lower genetic differentiation was detected among rivers than among ponds which might be related to limitations on gene flow. Demographic and temporal genetic data further indicates that flooding in rivers is unlikely to induce marked gene flow explaining the strong genetic differentiation at short geographical scale in such habitats. Finally, the demographic data suggest that some populations are transitory and subject to recurrent recolonization, a pattern that was also detected through genetic data.
Pronounced genetic population structure in a potentially vagile fish species (Pristipomoides multidens, Teleostei; Perciformes; Lutjanidae) from the East Indies triangle
Authors: OVENDEN JENNIFER R. , SALINI JOHN , O'CONNOR SALLY , STREET RAEWYN
Published: December 2004

The East Indies triangle, bordered by the Phillipines, Malay Peninsula and New Guinea, has a high level of tropical marine species biodiversity. Pristipomoides multidens is a large, long‐lived, fecund snapper species that is distributed throughout the East Indies and Indo‐Pacific. Samples were analysed from central and eastern Indonesia and northern Australia to test for genetic discontinuities in population structure. Fish (n = 377) were collected from the Indonesian islands of Bali, Sumbawa, Flores, West Timor, Tanimbar and Tual along with 131 fish from two northern Australian locations (Arafura and Timor Seas) from a previous study. Genetic variation in the control region of the mitochondrial genome was assayed using restriction fragment length polymorphism and direct sequencing. Haplotype diversity was high (0.67–0.82), as was intraspecific sequence divergence (range 0–5.8%). FST between pairs of populations ranged from 0 to 0.2753. Genetic subdivision was apparent on a small spatial scale; FST was 0.16 over 191 km (Bali/Sumbawa) and 0.17 over 491 km (Bali/Flores). Constraints to dispersal that contribute to, and maintain, the observed degree of genetic subdivision are experienced presumably by all life history stages of this tropical marine finfish. The constraints may include (1) little or no movement of eggs or larvae, (2) little or no home range or migratory movement of adults and (3) loss of larval cohorts due to transport of larvae away from suitable habitat by prevailing currents.
Reproductive effects and geographical distributions of twoWolbachiastrains infecting the Neotropical beetle,Chelymorpha alternansBoh. (Chrysomelidae, Cassidinae)
Authors: KELLER G. P. , WINDSOR D. M. , SAUCEDO J. M. , WERREN J. H.
Published: December 2004

Wolbachiaare maternally inherited endocellular bacteria known to alter insect host reproduction to facilitate their own transmission. MultipleWolbachiainfections are more common in tropical than temperate insects but few studies have investigated their dynamics in field populations. The beetle,Chelymorpha alternans, found throughout the Isthmus of Panama, is infected with two strains ofWolbachia,wCalt1 (99.2% of beetles) andwCalt2 (53%). Populations infected solely by thewCalt1 strain were limited to western Pacific Panama, whereas populations outside this region were either polymorphic for single (wCalt1) and double infections (wCalt1 +wCalt2) or consisted entirely of double infections. ThewCalt2 strain was not found as a single infection in the wild. Both strains caused cytoplasmic incompatibility (CI). ThewCalt1 strain caused weak CI (∼20%) and the double infection induced moderate CI (∼70–90%) in crosses with uninfected beetles. ThewCalt1 strain rescued about 75% of eggs fertilized by sperm fromwCalt2 males. Based on the relationships of beetle mtDNA and infection status, maternal transmission, and repeated population sampling we determined that the double infection invadedC.alternanspopulations about 100 000 years ago and that thewCalt2 strain appears to be declining in some populations, possibly due to environmental factors. This may be the first study to demonstrate an association between widespread strain loss and environmental factors in the field.
Differences in mycorrhizal preferences between two tropical orchids
Authors: OTERO J. TUPAC , ACKERMAN JAMES D. , BAYMAN PAUL
Published: December 2004

Orchids parasitize their mycorrhizal fungi and are dependent on them for seed germination. Controversy reigns over how specific the mycorrhizal association is in tropical species. Although there is little experimental evidence to support any viewpoint, some variation is known to exist. We compared mycorrhizal specificity and performance in two phylogenetically related epiphytic orchids from Puerto Rico, Tolumnia variegata and Ionopsis utricularioides (Oncidiinae) by integrating two techniques: phylogenetic analysis of mycorrhizal fungi based on nuclear ribosomal internal transcribed spacer (ITS) sequences, and symbiotic seed germination experiments. Most of the mycorrhizal isolates from T. variegata fell into four different clades of Ceratobasidium, while most of those from I. utricularioides were restricted to a single clade of the same genus. Seeds of T. variegata germinated equally well with fungi from both T. variegata and I. utricularioides, but seeds of I. utricularioides germinated significantly better with its own isolates. Seeds of I. utricularioides germinated and developed faster than those of T. variegata. Both the molecular phylogeny and the seed germination experiments showed that T. variegata is a generalist in its association with fungal symbionts. In contrast, I. utricularioides is more specialized and more effective at exploiting a specific fungal clade. Our data are consistent with the theoretical trade‐offs between specialized and generalized interactions.
Phylogeographical patterns in the American Pacific Northwest: lessons from the arionid slugProphysaon coeruleum
Authors: WILKE T. , DUNCAN N.
Published: December 2004

Some of the earliest studies of phylogenetic concordance involve native plants from the Pacific Northwest where many taxa showed clear genetic breaks between southern and northern populations. To test whether similar breaks also occur in invertebrate species with low dispersal capacities, genetic data from two mitochondrial genes are assembled for individuals of the arionid slugProphysaon coeruleumthroughout the species’ range. Bayesian inference revealed three major clades and a total of eight subclades. It is argued that the demographic and genealogical past ofP. coeruleumhas resulted in a deep and shallow phylogeographical structure. The deep structure is at least 2.6–5.9 million years old and therefore clearly predates the Pleistocene period. Superimposed on this structure is a shallow structure that is most likely less than 2 million years old and probably the result of Pleistocene perturbations. Molecular analyses revealed that the three known colour traits inP. coeruleumdo not represent monophyletic groups and that they do not match the patterns of genetic structure found. It is argued that the colour traits are perhaps a response to different levels of UV‐radiation. The study adds to the increasing evidence that the phylogeographical structure of some taxa is more complex than previously thought. Moreover, it shows that genealogical concordance should not be deduced from phylogeographical patterns alone but should be based on an understanding of timing and causes of historical processes that lead to those patterns.
Nest architecture and genetic differentiation in a species complex of Australian stingless bees
Authors: FRANCK P. , CAMERON E. , GOOD G. , RASPLUS J.‐Y. , OLDROYD B. P.
Published: December 2004

We investigated the taxonomic significance of nest shape and its putative role in speciation inTrigona(Heterotrigona)carbonariaandT.(H.)hockingsi, two sibling species of stingless bee species from eastern Australia. These species are primarily distinguished by their nest architecture, as in all other respects they are nearly identical. We genotyped 130 colonies from six locations in Queensland at 13 microsatellite loci together with 106 additional colonies from six other Indo‐PacificTrigonaspecies. Whether they were present in allopatry or in sympatry, colonies that displayed theT. carbonariaor theT. hockingsinest architecture could be unambiguously differentiated at the genetic level. However,T. hockingsicolonies were classifiable into two highly differentiated paraphyletic and geographically separate populations, one in northern and one in southern Queensland. These two populations probably belong to two distinct species,T. hockingsiandT. davenportinov. sp. Our results suggest that nest architecture characters are relevant but not sufficient criteria to identify species in this group. Consequently, modifications of nest architecture are probably not of prime importance in the speciation process of Australian stingless bees, although nest architecture differences probably result from relatively simple mechanisms. The rare interspecific hybrid colonies detected did not display a nest with an intermediate form betweenT. hockingsiandT. carbonaria.
Quantitative trait loci affecting knockdown resistance to high temperature in Drosophila melanogaster
Authors: NORRY F. M. , DAHLGAARD J. , LOESCHCKE V.
Published: December 2004

Knockdown resistance to high temperature is an ecologically important trait in small insects. A composite interval mapping was performed on the two major autosomes of Drosophila melanogaster to search for quantitative trait loci (QTL) affecting knockdown resistance to high temperature (KRHT). Two dramatically divergent lines from geographically different thermal environments were artificially selected on KRHT. These lines were crossed to produce two backcross (BC) populations. Each BC was analysed for 200 males with 18 marker loci on chromosomes 2 and 3. Three X‐linked markers were used to test for X‐linked QTL in an exploratory way. The largest estimate of autosome additive effects was found in the pericentromeric region of chromosome 2, accounting for 19.26% (BC to the low line) and 29.15% (BC to the high line) of the phenotypic variance in BC populations, but it could represent multiple closely linked QTL. Complete dominance was apparent for three QTL on chromosome 3, where heat‐shock genes are concentrated. Exploratory analysis of chromosome X indicated a substantial contribution of this chromosome to KRHT. The results show that a large‐effect QTL with dominant gene action maps on the right arm of chromosome 3. Further, the results confirm that QTL for heat resistance are not limited to chromosome 3.