bluuebunny/crossref_metadata_2025_split huggingface dataset:
To what extent does living in a group mean living with kin?
Authors: LUKAS D. , REYNOLDS V. , BOESCH C. , VIGILANT L. 
Published: June 2005

AbstractChimpanzees live in large groups featuring remarkable levels of gregariousness and cooperation among the males. Because males stay in their natal communities their entire lives and are hence expected to be living with male relatives, cooperation is therefore assumed to occur within one large ‘family’ group. However, we found that the average relatedness among males within several chimpanzee groups as determined by microsatellite analysis is in fact rather low, and only rarely significantly higher than average relatedness of females in the groups or of males compared across groups. To explain these findings, mathematical predictions for average relatedness according to group size, reproductive skew and sex bias in dispersal were derived. The results show that high average relatedness among the philopatric sex is only expected in very small groups, which is confirmed by a comparison with published data. Our study therefore suggests that interactions among larger number of individuals may not be primarily driven by kin relationships.
How to use molecular marker data to measure evolutionary parameters in wild populations
Authors: GARANT DANY , KRUUK LOESKE E. B. 
Published: June 2005

AbstractEstimating the genetic basis of phenotypic traits and the selection pressures acting on them are central to our understanding of the evolution and conservation of wild populations. However, obtaining such evolutionary‐related parameters is not an easy task as it requires accurate information on both relatedness among individuals and their breeding success. Polymorphic molecular markers are very useful in estimating relatedness between individuals and parentage analyses are now extensively used in most taxa. The next step in the application of molecular data to wild populations is to use them to derive estimates of evolutionary‐related parameters for quantitative traits, such as quantitative genetic parameters (e.g. heritability, genetic correlations) and measures of selection (e.g. selection gradients). Despite their great appeal and potential, the optimal use of molecular tools is still debated and it remains unclear how they should best be used to obtain reliable estimates of evolutionary parameters in the wild. Here, we review the methods available for estimating quantitative genetic and selection parameters and discuss their merits and shortcomings, to provide a tool that summarizes the potential uses of molecular data to obtain such parameters in wild populations.
Potential refugia in Taiwan revealed by the phylogeographical study of Castanopsis carlesii Hayata (Fagaceae)
Authors: CHENG YU‐PIN , HWANG SHIH‐YING , LIN TSAN‐PIAO 
Published: June 2005

AbstractIn this study, we examined spatial patterns of chloroplast DNA (cpDNA) variation in a total of 30 populations of Castanopsis carlesii Hayata (Fagaceae), a subtropical and temperate tree species, including 201 individuals sampled throughout Taiwan. By sequencing two cpDNA fragments using universal primers (the trnL intron and the trnV‐trnM intergenic spacer), we found a total of 1663 bp and 21 polymorphic sites. These gave rise to a total of 28 cpDNA haplotypes. The level of differentiation among the populations studied was relatively high (GST = 0.723). Two ancestral haplotypes are widely distributed. The Central Mountain Ridge (CMR) of Taiwan represents an insurmountable barrier to the east–west gene flow of C. carlesii. Among the populations studied, three separated populations, at Lienhuachih, Fushan and Lichia, have high nucleotide diversity. Estimates of NST–GST for populations on both sides of the CMR indicate that no phylogeographical structure exists. According to the genealogical tree, number of rare haplotype and population genetic divergence, this study suggests that two potential refugia existed during the last glaciation: the first refugium was located in a region to the north of Hsuehshan Range (HR) and west of the CMR; the second refugium was located in south, especially southeastern Taiwan. In fact, the second refugium happens to be the same as that reported for Quercus glauca. A ‘star‐like’ genealogy is characteristic when all haplotypes rapidly coalesce and is a general outcome of population expansion. The neutrality test and mismatch distribution also suggest demographic expansion recovering from a bottleneck.
Phylogeography of the cyprinid Squalius aradensis and implications for conservation of the endemic freshwater fauna of southern Portugal
Authors: MESQUITA N. , HÄNFLING B. , CARVALHO G. R. , COELHO M. M. 
Published: June 2005

AbstractThe Iberian cyprinid fauna, characterized by the presence of numerous endemic species, has suffered from significant habitat degradation. The critically endangered Squalius aradensis is restricted to small drainages of southern Portugal, habitats that typically exhibit a characteristic Mediterranean‐type heterogeneous hydrological system throughout the year, including alternation of flooding events during winter and complete drought in large river sections during summer. To assess the effect of historical and recent processes on genetic diversity in S. aradensis we examined within‐ and among‐population variability in cytochrome b and six polymorphic microsatellite loci. Estimates of genetic diversity in time and space through the combined use of traditional Φ‐/F‐statistics, phylogenetic trees, ordination methods and nested clade analysis indicated significant and congruent structuring among populations. Data suggest that the Arade drainage represent the evolutionary centre of the species, with subsequent allopatric fragmentation across drainages. Factors other than isolation by distance strongly affected the within‐drainage genetic differentiation observed in these Mediterranean‐type drainages, including recent population expansion from a bottleneck event and restricted gene flow imposed by a long‐term barrier (brackish water area). Significant correlation was found between S. aradensis allelic diversity and upstream drainage area. The relevance of findings for conservation issues is discussed in relation to local intermittent hydrological conditions, the highly restricted distribution and the critically endangered status of the species.
Habitat barriers limit gene flow and illuminate historical events in a wide‐ranging carnivore, the American puma
Authors: MCRAE B. H. , BEIER P. , DEWALD L. E. , HUYNH L. Y. , KEIM P. 
Published: June 2005

AbstractWe examined the effects of habitat discontinuities on gene flow among puma (Puma concolor) populations across the southwestern USA. Using 16 microsatellite loci, we genotyped 540 pumas sampled throughout the states of Utah, Colorado, Arizona, and New Mexico, where a high degree of habitat heterogeneity provides for a wide range of connective habitat configurations between subpopulations. We investigated genetic structuring using complementary individual‐ and population‐based analyses, the latter employing a novel technique to geographically cluster individuals without introducing investigator bias. The analyses revealed genetic structuring at two distinct scales. First, strikingly strong differentiation between northern and southern regions within the study area suggests little migration between them. Second, within each region, gene flow appears to be strongly limited by distance, particularly in the presence of habitat barriers such as open desert and grasslands. Northern pumas showed both reduced genetic diversity and greater divergence from a hypothetical ancestral population based on Bayesian clustering analyses, possibly reflecting a post‐Pleistocene range expansion. Bayesian clustering results were sensitive to sampling density, which may complicate inference of numbers of populations when using this method. The results presented here build on those of previous studies, and begin to complete a picture of how different habitat types facilitate or impede gene flow among puma populations.
Transgene escape: what potential for crop–wild hybridization?
Authors: ARMSTRONG T. T. , FITZJOHN R. G. , NEWSTROM L. E. , WILTON A. D. , LEE W. G. 
Published: June 2005

AbstractTo date, regional surveys assessing the risk of transgene escape from GM crops have focused on records of spontaneous hybridization to infer the likelihood of crop transgene escape. However, reliable observations of spontaneous hybridization are lacking for most floras, particularly outside Europe. Here, we argue that evidence of interspecific reproductive compatibility derived from experimental crosses is an important component of risk assessment, and a useful first step especially where data from field observations are unavailable. We used this approach to assess the potential for transgene escape via hybridization for 123 widely grown temperate crops and their indigenous and naturalized relatives present in the New Zealand flora. We found that 66 crops (54%) are reproductively compatible with at least one other indigenous or naturalized species in the flora. Limited reproductive compatibility with wild relatives was evident for a further 12 crops (10%). Twenty‐five crops (20%) were found to be reproductively isolated from all their wild relatives in New Zealand. For the remaining 20 crops (16%), insufficient information was available to determine levels of reproductive compatibility with wild relatives. Our approach may be useful in other regions where spontaneous crop–wild hybridization has yet to be well documented.
A new method for estimating the size of small populations from genetic mark–recapture data
Authors: MILLER CRAIG R. , JOYCE PAUL , WAITS LISETTE P. 
Published: June 2005

AbstractThe use of non‐invasive genetic sampling to estimate population size in elusive or rare species is increasing. The data generated from this sampling differ from traditional mark–recapture data in that individuals may be captured multiple times within a session or there may only be a single sampling event. To accommodate this type of data, we develop a method, named capwire, based on a simple urn model containing individuals of two capture probabilities. The method is evaluated using simulations of an urn and of a more biologically realistic system where individuals occupy space, and display heterogeneous movement and DNA deposition patterns. We also analyse a small number of real data sets. The results indicate that when the data contain capture heterogeneity the method provides estimates with small bias and good coverage, along with high accuracy and precision. Performance is not as consistent when capture rates are homogeneous and when dealing with populations substantially larger than 100. For the few real data sets where N is approximately known, capwire's estimates are very good. We compare capwire's performance to commonly used rarefaction methods and to two heterogeneity estimators in program capture: Mh‐Chao and Mh‐jackknife. No method works best in all situations. While less precise, the Chao estimator is very robust. We also examine how large samples should be to achieve a given level of accuracy using capwire. We conclude that capwire provides an improved way to estimate N for some DNA‐based data sets. Capwire is available at http://www.cnr.uidaho.edu/lecg/.
Identification and characterization of QTL underlying whole‐plant physiology in Arabidopsis thaliana: δ13C, stomatal conductance and transpiration efficiency
Authors: JUENGER THOMAS E. , MCKAY JOHN K. , HAUSMANN NEIL , KEURENTJES JOOST J. B. , SEN SÁUNAK , STOWE KIRK A. , DAWSON TODD E. , SIMMS ELLEN L. , RICHARDS JAMES H. 
Published: June 2005

ABSTRACTWater limitation is one of the most important factors limiting crop productivity world‐wide and has likely been an important selective regime influencing the evolution of plant physiology. Understanding the genetic and physiological basis of drought adaptation is therefore important for improving crops as well as for understanding the evolution of wild species. Here, results are presented from quantitative trait loci (QTL) mapping of flowering time (a drought escape mechanism) and carbon stable isotope ratio (δ13C) (a drought‐avoidance mechanism) in Arabidopsis thaliana. Whole‐genome scans were performed using multiple‐QTL models for both additive and epistatic QTL effects. We mapped five QTL affecting flowering time and five QTL affecting δ13C, but two genomic regions contained QTL with effects on both traits, suggesting a potential pleiotropic relationship. In addition, we observed QTL–QTL interaction for both traits. Two δ13C QTL were captured in near‐isogenic lines to further characterize their physiological basis. These experiments revealed allelic effects on δ13C through the upstream trait of stomatal conductance with subsequent consequences for whole plant transpiration efficiency and water loss. Our findings document considerable natural genetic variation in whole‐plant, drought resistance physiology of Arabidopsis and highlight the value of quantitative genetic approaches for exploring functional relationships regulating physiology.
Auxin and ethylene interactions control mitotic activity of the quiescent centre, root cap size, and pattern of cap cell differentiation in maize
Authors: PONCE GEORGINA , BARLOW PETER W. , FELDMAN LEWIS J. , CASSAB GLADYS I. 
Published: June 2005

ABSTRACTRoot caps (RCs) are the terminal tissues of higher plant roots. In the present study the factors controlling RC size, shape and structure were examined. It was found that this control involves interactions between the RC and an adjacent population of slowly dividing cells, the quiescent centre, QC. Using the polar auxin transport inhibitor 1‐N‐naphthylphthalamic acid (NPA), the effects of QC activation on RC gene expression and border cell release was characterized. Ethylene was found to regulate RC size and cell differentiation, since its addition, or the inhibition of its synthesis, affected RC development. The stimulation of cell division in the QC following NPA treatment was reversed by ethylene, and quiescence was re‐established. Moreover, inhibition of both ethylene synthesis and auxin polar transport triggered a new pattern of cell division in the root epidermis and led to the appearance of supernumerary epidermal cell files with cap‐like characteristics. The data suggest that the QC ensures an ordered internal distribution of auxin, and thereby regulates not only the planes of growth and division in both the root apex proper and the RC meristem, but also regulates cell fate in the RC. Ethylene appears to regulate the auxin redistribution system that resides in the RC. Experiments with Arabidopsis roots also reveal that ethylene plays an important role in regulating the auxin sink, and consequently cell fate in the RC.
Circadian regulation of leaf hydraulic conductance in sunflower (Helianthus annuus L. cv Margot)
Authors: NARDINI ANDREA , SALLEO SEBASTIANO , ANDRI SERGIO 
Published: June 2005

ABSTRACTThe circadian regulation of leaf hydraulic conductance (Kleaf) was investigated in Helianthus annuus L. (sunflower). Kleaf was measured with an high pressure flow meter during the light and dark period from plants growing at a photoperiod of 12 h. Kleaf was 4.0 e−4 kg s−1 m−2 MPa−1 during the light period (LL) and 30–40% less during the dark period (DL). When photoperiod was inverted and leaves were measured for Kleaf at their subjective light or dark periods, Kleaf adjusted to the new conditions requiring 48 h for increasing from dark to light values and 4 d for the opposite transition. Plants put in continuous dark showed Kleaf oscillating from light to dark values in phase with their subjective photoperiod indicating that Kleaf changes were induced by the circadian clock. Several cuts through the minor veins reduced leaf hydraulic resistance (Rleaf) of both LL and DL to the same value (1.0 e + 3 MPa m2 s kg−1) that equalled the vascular resistance (Rv). The contribution of the non‐vascular leaf resistance (Rnv) to Rleaf was of 71.9% in DL and of 58.4% in LL. The dominant Rnv was shown to be reversibly modulated by mercurials, suggesting that aquaporins play a role in diurnal changes of Kleaf.
Uptake and assimilation of nitrogen from solutions containing multiple N sources
Authors: THORNTON BARRY , ROBINSON DAVID 
Published: June 2005

ABSTRACTWe assessed the extent to which plants can acquire amino acids when supplied as single N‐sources or when plants have access to a mixture of amino‐ and inorganic N sources. Because the uptake of different N‐sources is temperature‐dependent, the effects of temperature on amino‐N uptake were also tested. Lolium perenne (perennial rye‐grass) was grown hydroponically at 11 °C or 21 °C. Uptake of N was determined using 15N tracers at the growth temperature from solutions containing either nitrate, ammonium or glycine as single N sources and from a mixture containing all three N‐forms. Estimates of the relative importance of amino acids such as glycine to the total N budget of plants will have been underestimated in studies where uptake was determined in single source solutions compared with those from solutions containing a mixture of N‐forms. The proportion of total N acquired from the mixed N source as ammonium increased as temperature was reduced. Regarding the uptake and initial metabolism of glycine, uptake was probably the rate limiting step at 11 °C whilst it was the metabolism of glycine to serine at 21 °C. Although 15N incorporation into the plant amino‐N pool was generally in proportion to the abundance of individual amino acids, its incorporation into the glycine pool was sometimes significantly less than predicted.
Contact Between Good Friends: What Limiting Dilution Analysis Taught Us
Authors: Waldmann H. 
Published: June 2005

AbstractThe demonstration in the 1960s that T cells collaborated with B cells in enabling antibody responses to simple protein antigens opened up the challenge of how to investigate the interactions of two rare antigen‐specific lymphocytes within a vast population. One idea was that T cells made soluble factors that could activate B cells at a distance; the other was that rare T cells and B cells came into contact. Using limiting dilution analysis, we asked the question ‘How many B cells could a single T cell collaborate with in the short term?’ Unequivocally, the answer was just one. This implied a need for cell contact, and coupled with the observation for genetic restriction in T‐cell/B‐cell co‐operation, seemed to make a watertight case for direct coupling. Claims of diffusible antigen‐specific factors undermined the importance of our findings at that time. Remarkably, those claims have not yet been retracted and our original findings that collaborating T cells and B cells must come into contact have never achieved the recognition that they deserved.
IgM Accelerates Affinity Maturation
Authors: Corley R. B. , Morehouse E. M. , Ferguson A. R. 
Published: June 2005

AbstractSecreted IgM is a potent adjuvant that concentrates antigen into secondary lymphoid organs and initiates antibody responses, germinal centre formation and is crucial in resolving infections. The current studies investigated the influence of specific IgM on both the quantity and quality of antibody produced in response to T‐dependent and T‐independent antigens. The addition of IgM to either antigen had no significant effect on the titre or duration of antibody responses. However, the presence of specific IgM led to accelerated affinity maturation when mice were challenged with low doses of IgM‐containing immune complexes (IgM‐IC) of T‐dependent antigens compared with antigen alone. Interestingly, the administration of higher concentrations of IgM‐IC increased follicular deposition of antigen but did not result in accelerated affinity maturation or in higher antibody affinities. The administration of IgM complexed with T‐independent antigens had no effect on antibody titre, duration or affinity maturation, despite increased antigen deposition in lymphoid follicles. Together, these results demonstrate that IgM accelerates affinity maturation in immune responses to T‐dependent antigens and implies an antigen optimum exists for the generation of high affinity antibodies. The data also suggest IgM plays an important role in the induction of CD4 T cells, facilitating germinal centre formation and function.
Household pit latrines as a potential source of the fly Musca sorbens– a one year longitudinal study from The Gambia
Authors: Emerson Paul M. , Simms Victoria M. , Makalo Pateh , Bailey Robin L. 
Published: June 2005

SummaryObjectives  To assess whether the trachoma vector Musca sorbens was breeding in household latrines in a trachoma‐endemic part of The Gambia.Methods  Longitudinal study of flies emerging from 16 sentinel household latrines selected at random from a list of all latrines present in four Gambian villages. Latrines were surveyed and fly traps were set over the drop hole for 24 h once per month for a year.Results  All the sentinel latrines were of the ‘Gambian improved household latrine’ design, which has a cement slab but is not ventilated or fly‐proofed. The latrines were all in regular use by a family, mean number of users per latrine 14.8 (SD 8.0, range 2–29). Of 55 351 flies caught in 192 catches 54 130 (97.8%) were Chrysomya albiceps, 690 (1.2%) Musca domestica, 466 (0.8%) Chrysomya regalis and 65 (0.1%) M. sorbens. Of the M. sorbens caught 61 (93.8%) were female.Conclusions  Gambian improved household pit latrines cannot be considered a source of the trachoma vector M. sorbens, and the promotion of pit latrines as a method to reduce M. sorbens is warranted. A large number of C. albiceps were caught emerging from the latrines, but this species is not considered to be of medical importance.
Predictors of compliance with community‐directed ivermectin treatment in Uganda: quantitative results
Authors: Nuwaha Fred , Okware Joseph , Ndyomugyenyi Richard 
Published: June 2005

SummaryIn order to identify the factors influencing compliance with mass ivermectin treatment for onchocerciasis control, a cross‐sectional study was carried out in Bushenyi District, Uganda. Data were collected by interviewing 839 individuals who were randomly selected from 30 clusters where onchocerciasis is endemic. Information was collected on compliance with ivermectin treatment, socio‐demographic characteristics, perception of personal susceptibility to onchocerciasis, knowledge about cause/transmission of onchocerciasis, knowledge of signs and symptoms of onchocerciasis, treatment of onchocerciasis, benefits and dangers of taking ivermectin, organization of distribution of ivermectin, work and selections of community drug distributors (CDDs), social influence and support to take ivermectin and on barriers and supports towards compliance with ivermectin treatment. The major factors favouring compliance were: perceiving CDDs as doing their work well, believing that measuring height is the best way to determine one's dose of ivermectin, having social support from one's family, saying that ivermectin treatment costs nothing, perceiving personal risk of onchocerciasis, believing that ivermectin prevents onchocerciasis and perceiving radios as supporting treatment with ivermectin. The strongest predictor of compliance with ivermectin treatment is perceiving CDDs as doing their work well with adjusted odds ratios of 5.54 (95% CI: 3.19–9.62). In order to improve compliance with ivermectin treatment, CDDs need to be well‐facilitated and ivermectin distribution should be free. Health education is necessary so that people perceive themselves to be at risk of onchocerciasis and to understand the rationale of using height for dose determination. The health education should target the family and use radios.