bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phylogeny and biogeography of Croton alabamensis (Euphorbiaceae), a rare shrub from Texas and Alabama, using DNA sequence and AFLP data
Authors: VAN EE BENJAMIN W. , JELINSKI NICOLAS , BERRY PAUL E. , HIPP ANDREW L. 
Published: June 2006

Abstract Croton alabamensis (Euphorbiaceae s.s.) is a rare plant species known from several populations in Texas and Alabama that have been assigned to var. texensis and var. alabamensis, respectively. We performed maximum parsimony, maximum likelihood, and Bayesian analyses of DNA sequences from the nuclear ribosomal internal transcribed spacer (ITS) and 5.8S regions and chloroplast trnL‐trnF regions from collections of the two varieties of C. alabamensis and from outgroup taxa. C. alabamensis emerges alone on a long branch that is sister to Croton section Corylocroton and the Cuban endemic genus Moacroton. Molecular clock analysis estimates the split of C. alabamensis from its closest relatives in sect. Corylocroton at 41 million years ago, whereas the split of the two varieties of C. alabamensis occurred sometime in the Quaternary. Amplified fragment length polymorphism (AFLP) analyses were performed using two selective primer pairs on a larger sampling of accessions (22 from Texas, 17 from Alabama) to further discriminate phylogenetic structure and quantify genetic diversity. Using both neighbour joining and minimum evolution, the populations from the Cahaba and Black Warrior watersheds in Alabama form two well‐separated groups, and in Texas, geographically distinct populations are recovered from Fort Hood, Balcones Canyonlands, and Pace Bend Park. Most of the molecular variance is accounted for by variance within populations. Approximately equal variance is found among populations within states and between states (varieties). Genetic distance between the Texas populations is significantly less than genetic distance between the Alabama populations. Both sequence and AFLP data support the same relationships between the varieties of C. alabamensis and their outgroup, while the AFLP data provide better resolution among the different geographical regions where C. alabamensis occurs. The conservation implications of these findings are discussed.
Comparison of gene expression in segregating families identifies genes and genomic regions involved in a novel adaptation, zinc hyperaccumulation
Authors: FILATOV VICTOR , DOWDLE JOHN , SMIRNOFF NICHOLAS , FORD‐LLOYD BRIAN , NEWBURY H. JOHN , MACNAIR MARK R. 
Published: June 2006

AbstractOne of the challenges of comparative genomics is to identify specific genetic changes associated with the evolution of a novel adaptation or trait. We need to be able to disassociate the genes involved with a particular character from all the other genetic changes that take place as lineages diverge. Here we show that by comparing the transcriptional profile of segregating families with that of parent species differing in a novel trait, it is possible to narrow down substantially the list of potential target genes. In addition, by assuming synteny with a related model organism for which the complete genome sequence is available, it is possible to use the cosegregation of markers differing in transcription level to identify regions of the genome which probably contain quantitative trait loci (QTLs) for the character. This novel combination of genomics and classical genetics provides a very powerful tool to identify candidate genes. We use this methodology to investigate zinc hyperaccumulation in Arabidopsis halleri, the sister species to the model plant, Arabidopsis thaliana. We compare the transcriptional profile of A. halleri with that of its sister nonaccumulator species, Arabidopsis petraea, and between accumulator and nonaccumulator F3s derived from the cross between the two species. We identify eight genes which consistently show greater expression in accumulator phenotypes in both roots and shoots, including two metal transporter genes (NRAMP3 and ZIP6), and cytoplasmic aconitase, a gene involved in iron homeostasis in mammals. We also show that there appear to be two QTLs for zinc accumulation, on chromosomes 3 and 7.
Evolution of Mesobuthus gibbosus (Brullé, 1832) (Scorpiones: Buthidae) in the northeastern Mediterranean region
Authors: PARMAKELIS A. , STATHI I. , CHATZAKI M. , SIMAIAKIS S. , SPANOS L. , LOUIS C. , MYLONAS M. 
Published: June 2006

AbstractSequence data derived from two mitochondrial markers, 16S rRNA and COI genes, were used to infer the evolutionary history of 47 insular and mainland populations covering most of the distributional range of the northeastern Mediterranean scorpion species Mesobuthus gibbosus. Based on the estimated divergence times of Mesobuthus lineages, the temporal frame of the genus differentiation in the northeastern Mediterranean region is placed in middle Miocene (15 million years ago). The biogeographic affinities of M. gibbosus populations point towards a mainly vicariant pattern of differentiation of the species which is consistent with the geological events that transformed the Aegean region during the period from 12 to 5 million years ago. M. gibbosus is an old northeastern Mediterranean species that has retained valuable bits of genetic information, reflecting some of the oldest vicariant events that have occurred in the area. Most importantly, the history witnessed by M. gibbosus has not been obscured by more recent palaeoevents of the region. Therefore, the case of M. gibbosus is in favour of a taxon‐oriented ‘perception’ of the natural history of a given area.
Mating system and reproductive success in eastern Pacific harbour seals
Authors: HAYES SEAN A. , PEARSE DEVON E. , COSTA DANIEL P. , HARVEY JAMES T. , LE BOEUF BURNEY J. , GARZA JOHN CARLOS 
Published: June 2006

AbstractHarbour seals sometimes breed along inland travel corridors where females become clustered in space and time and males establish underwater acoustic display territories similar to terrestrial arenas known as resource‐based leks. Under these conditions, we predicted that higher levels of polygyny would be observed than has been previously reported for this species mating in open coast environments without travel corridors. Reproductive success (RS) of 70 males was measured using 20 microsatellite DNA loci and likelihood‐based paternity analysis of 136 offspring collected over 3 years. Most males were assigned either zero or one paternity with 80% confidence. The greatest number of pups assigned to one male in a season was two. Variance in RS was higher for males than females (which are biologically limited to one offspring per year) indicating low to mild polygyny. In addition, distributions of relatedness values among pups within year classes did not differ significantly from a simulated distribution with R = 0, indicating that half‐siblings were uncommon. Overall, polygyny levels were low relative to terrestrial pinniped mating systems and similar to observations from a harbour seal population along an open coast. Due to large confidence intervals associated with our results, we cannot rule out the hypothesis that a travel corridor might increase the degree of polygyny skew relative to that observed in open coast environments. Habitat appeared to influence male strategies as the most successful males in open coast environments patrolled offshore, while the most successful male in this study defended a territory along the travel corridor.
Restricted mating dispersal and strong breeding group structure in a mid‐sized marsupial mammal (Petrogale penicillata)
Authors: HAZLITT S. L. , SIGG D. P. , ELDRIDGE M.D.B. , GOLDIZEN A. W. 
Published: June 2006

AbstractEcological genetic studies have demonstrated that spatial patterns of mating dispersal, the dispersal of gametes through mating behaviour, can facilitate inbreeding avoidance and strongly influence the structure of populations, particularly in highly philopatric species. Elements of breeding group dynamics, such as strong structuring and sex‐biased dispersal among groups, can also minimize inbreeding and positively influence levels of genetic diversity within populations. Rock‐wallabies are highly philopatric mid‐sized mammals whose strong dependence on rocky terrain has resulted in series of discreet, small colonies in the landscape. Populations show no signs of inbreeding and maintain high levels of genetic diversity despite strong patterns of limited gene flow within and among colonies. We used this species to investigate the importance of mating dispersal and breeding group structure to inbreeding avoidance within a ‘small’ population. We examined the spatial patterns of mating dispersal, the extent of kinship within breeding groups, and the degree of relatedness among brush‐tailed rock‐wallaby breeding pairs within a colony in southeast Queensland. Parentage data revealed remarkably restricted mating dispersal and strong breeding group structuring for a mid‐sized mammal. Breeding groups showed significant levels of female kinship with evidence of male dispersal among groups. We found no evidence for inbreeding avoidance through mate choice; however, anecdotal data suggest the importance of life history traits to inbreeding avoidance between first‐degree relatives. We suggest that the restricted pattern of mating dispersal and strong breeding group structuring facilitates inbreeding avoidance within colonies. These results provide insight into the population structure and maintenance of genetic diversity within colonies of the threatened brush‐tailed rock‐wallaby.
Long‐term paternity skew and the opportunity for selection in a mammal with reversed sexual size dimorphism
Authors: ROSSITER STEPHEN J. , RANSOME ROGER D. , FAULKES CHRISTOPHER G. , DAWSON DEBORAH A. , JONES GARETH 
Published: June 2006

AbstractMost mammalian groups are characterized by male‐biased sexual size dimorphism, in which size‐dependent male–male competition and reproductive skew are tightly linked. By comparison, little is known about the opportunity for sexual selection in mammalian systems without male‐biased dimorphism, where the traits under sexual selection might be less obvious. We examined 10 years of parentage data in a colony of greater horseshoe bats (Rhinolophus ferrumequinum) to determine the magnitude of male reproductive skew and the opportunity for sexual selection in a mammal in which females are the larger sex. Annual paternity success was weakly skewed but consistent patterns led to strong longitudinal paternity skew among breeders. Just three males accounted for a third of all paternity assignments, representing at least a fifth of all colony offspring born in a decade. Paternity success was in part determined by age but was not influenced by dispersal status. Our results show that paternity skew and the opportunity for sexual selection in a species with reversed sexual size dimorphism can approach levels reported for classical examples of species with polygyny and male‐biased dimorphism, even where the traits under sexual selection are not known.
Divergence and diversity: lessons from an arctic–alpine distribution (Pardosa saltuaria group, Lycosidae)
Authors: MUSTER CHRISTOPH , BERENDONK THOMAS U. 
Published: June 2006

AbstractThe relationship of interpopulation genetic divergence and within‐population diversity has been studied for many temperate species in Europe, but not for the cold‐adapted fauna. Here we present the first European‐wide phylogeographical study of an arctic–alpine distribution in invertebrates, focusing on wolf spiders of the Pardosa saltuaria group. One hundred twenty‐seven (127) specimens from 14 populations were examined. Within Europe, these populations were distributed among six high mountain ranges and Scandinavia. We sequenced the whole 921 base pair mitochondrial (mt) ND1 gene. The resulting 55 unique haplotypes form three monophyletic phylogroups of deep divergence: a Pyrenean, a Balkan and a ‘northern’ clade. Genetic distances (3.6–4.0%) between the major clades indicate that the arctic–alpine range disjunction was initiated by vicariance events, which precede the four major Alpine glaciations. However, low divergence and incomplete lineage sorting within the ‘northern clade’ suggest a late Pleistocene separation of the Alpine, Scandinavian, Carpathian and Sudetian populations. Thus, we provide evidence for a multiglacial origin of arctic–alpine distributions in Europe, i.e. the current disjunction results from range fragmentation in several glacial cycles. The pattern of genetic diversity within populations seems predominantly determined by historical factors, but is modified by contemporary aspects. Overall, diversity and divergence are negatively correlated. We suggest that low diversity values might result from (i) ancient bottlenecking during warm interglacial periods, as seen in the Pyrenees and Balkans; (ii) recent bottlenecking in small modern areas, as seen in the Giant Mountains and Bohemian Forest; and (iii) dispersal bottlenecking in northern Scandinavia.
Sea‐level and tectonic control of middle to late Pleistocene turbidite systems in Santa Monica Basin, offshore California
Authors: NORMARK WILLIAM R. , PIPER DAVID J. W. , SLITER RAY 
Published: June 2006

AbstractSmall turbidite systems offshore from southern California provide an opportunity to track sediment from river source through the turbidity‐current initiation process to ultimate deposition, and to evaluate the impact of changing sea level and tectonics. The Santa Monica Basin is almost a closed system for terrigenous sediment input, and is supplied principally from the Santa Clara River. The Hueneme fan is supplied directly by the river, whereas the smaller Mugu and Dume fans are nourished by southward longshore drift. This study of the Late Quaternary turbidite fill of the Santa Monica Basin uses a dense grid of high‐resolution seismic‐reflection profiles tied to new radiocarbon ages for Ocean Drilling Program (ODP) Site 1015 back to 32 ka. Over the last glacial cycle, sedimentation rates in the distal part of Santa Monica Basin averaged 2–3 mm yr−1, with increases at times of extreme relative sea‐level lowstand. Coarser‐grained mid‐fan lobes prograded into the basin from the Hueneme, Mugu and Dume fans at times of rapid sea‐level fall. These pulses of coarse‐grained sediment resulted from river channel incision and delta cannibalization. During the extreme lowstand of the last glacial maximum, sediment delivery was concentrated on the Hueneme Fan, with mean depositional rates of up to 13 mm yr−1 on the mid‐ and upper fan. During the marine isotope stage (MIS) 2 transgression, enhanced rates of sedimentation of > 4 mm yr−1 occurred on the Mugu and Dume fans, as a result of distributary switching and southward littoral drift providing nourishment to these fan systems. Longer‐term sediment delivery to Santa Monica Basin was controlled by tectonics. Prior to MIS 10, the Anacapa ridge blocked the southward discharge of the Santa Clara River into the Santa Monica Basin. The pattern and distribution of turbidite sedimentation was strongly controlled by sea level through the rate of supply of coarse sediment and the style of initiation of turbidity currents. These two factors appear to have been more important than the absolute position of sea level.
Defining the rectum: surgically, radiologically and anatomically
Authors: Salerno G. , Sinnatamby C. , Branagan G. , Daniels I. R. , Heald R. J. , Moran B. J. 
Published: June 2006

AbstractThe terminology used in relation to the rectum varies considerably, added to this there is the subjective nature of clinical assessment and variability in the anatomy of the rectum and anus. It is imperative that definitions are clarified and standardized for use by all members of the multidisciplinary team involved in the care of patients with rectal cancer.
Developments in the use of chemoradiotherapy in rectal cancer
Authors: Sebag‐Montefiore D. 
Published: June 2006

AbstractThis paper reviews the current evidence available from phase III trials of combination pre‐operative chemoradiotherapy (CRT) in the treatment of rectal cancer. There is clear evidence that CRT is superior to long‐course radiotherapy (LRT). However, the end‐points and definitions used must be standardized for future clinical trials of combination CRT.
The need for future surgical low rectal cancer studies
Authors: Daniels I. R. , Strassburg J. , Moran B. J. 
Published: June 2006

AbstractOptimal surgery remains the mainstay of best outcome for rectal cancer. The demonstration, during the 3rd Annual Pelican Surgical Workshop Symposium, of an abdomino‐perineal excision (APE) performed in the ‘Berlin position’, further added to the debate on optimal surgical technique. Much interest was created at the 1st Pelican symposium with the demonstration, by the Swedish surgeon Dr Torbjorn Holm, of a prone APE and the delivery of a ‘cylindrical’ specimen and the potential to reduce local recurrence using this approach. The high rates of local recurrence following APE and the discussions as to optimal technique have led to the development of a proposed MERCURY Study Group study to assess the benefit of a radical APE, with careful assessment of the impact that this operation may have on morbidity. A German study has also been proposed adopting the UK's multidisciplinary team approach. It aims at targeting preoperative chemoradiotherapy at those patients in whom a radical APE or total mesorectal excision is likely to result in an involved surgical resection margin. In this article we review the evidence for improving the surgical technique for low rectal cancer. We believe improvements may be best achieved through continued European prospective, multi‐centre, multidisciplinary studies.
A personal view on laparoscopic rectal cancer surgery
Authors: Cecil T. D. , Taffinder N. , Gudgeon A. M. 
Published: June 2006

AbstractBenefits such as reduced morbidity and shorter length of stay have been demonstrated for laparoscopic colon cancer resection, Laparoscopic rectal cancer surgery is thought to be more challenging and it is not clear if it offers the same benefits. There are concerns about oncological outcome and anastomotic technique and complications. In this review we discuss the difficulties and challenges of laparoscopic rectal cancer surgery within the context of our own personal experience and with regard to some of the current literature. We propose that laparoscopic and open rectal cancer surgery both have a role and the challenge is selection of appropriate patients for each technique.
Quality of life and sexual function following surgery for rectal cancer
Authors: Fisher S. E. , Daniels I. R. 
Published: June 2006

AbstractThe last 20 years have seen enormous strides forward in the treatment of rectal cancer with the development of improved surgical technique, tumour staging, histopathological audit and multidisciplinary team (MDT) management with emphasis on improving survival and reducing local recurrence rates. However, each rectal cancer discussed at the MDT meeting involves an individual patient. The quality of life for each patient must be taken into account when making treatment decisions, which sometimes may not fit with ‘standard’ treatment guidelines as the individual patient does not have a ‘standard’ tumour. For one patient with a tumour 5 cm above the anal verge, a low anterior resection may maintain quality of life with no incontinence and preservation of urinary and sexual function. For another with a tumour at the same level, preoperative chemo‐radiotherapy may exacerbate mild incontinence and a low resection may result in a ‘perineal stoma’. A decision to perform an abdomino‐perineal excision (APE) must not be considered a failure of surgical treatment or be seen as a suboptimal centre by having a high APE rate. On the contrary, APE rates should represent sub‐specialization and patient selection. Indeed, good function from a permanent stoma may be better than bad function from a poorly functioning coloanal pouch. Having improved tumour staging, surgical technique, oncological treatment and histopathological assessment, quality of life must not be forgotten. Both quality and quantity of life are important to all patients.
A synthetic de‐greening gene circuit provides a reporting system that is remotely detectable and has a re‐set capacity
Authors: Antunes Mauricio S. , Ha Suk‐Bong , Tewari‐Singh Neera , Morey Kevin J. , Trofka Anna M. , Kugrens Paul , Deyholos Michael , Medford June I. 
Published: June 2006

SummaryPlants have evolved elegant mechanisms to continuously sense and respond to their environment, suggesting that these properties can be adapted to make inexpensive and widely used biological monitors, or sentinels, for human threats. For a plant to be a sentinel, a reporting system is needed for large areas and widespread monitoring. The reporter or readout mechanism must be easily detectable, allow remote monitoring and provide a re‐set capacity; all current gene reporting technologies fall short of these requirements. Chlorophyll is one of the best‐recognized plant pigments with an already well‐developed remote imaging technology. However, chlorophyll is very abundant, with levels regulated by both genetic and environmental factors. We designed a synthetic de‐greening circuit that produced rapid chlorophyll loss on perception of a specific input. With induction of the de‐greening circuit, changes were remotely detected within 2 h. Analyses of multiple de‐greening circuits suggested that the de‐greening circuit functioned, in part, via light‐dependent damage to photosystem cores and the production of reactive oxygen species. Within 24–48 h of induction, an easily recognized white phenotype resulted. Microarray analysis showed that the synthetic de‐greening initiated a process largely distinct from normal chlorophyll loss in senescence. Remarkably, synthetically de‐greened white plants re‐greened after removal of the inducer, providing the first easily re‐settable reporter system for plants and the capacity to make re‐settable biosensors. Our results showed that the de‐greening circuit allowed chlorophyll to be employed as a simple but powerful reporter system useful for widespread areas.
On sampling the upper crustal reservoir of the NE Pacific Ocean
Authors: JOHNSON H. P. , BAROSS J. A. , BJORKLUND T. A. 
Published: June 2006

AbstractThe oceanic upper crustal reservoir is a 600‐m thick layer of porous and permeable basaltic rock that forms the uppermost igneous basement underlying the global ocean. Pore spaces within this fluid aquifer contain a significant fraction of the global seawater, and active circulation through this reservoir has profound influence on the chemical composition of the ocean, strongly impacting the biological environment near the sea surface. Because of the relative inaccessibility of the deep seafloor, where hydrothermal fluid discharges and seawater re‐charges the oceanic crustal aquifer, our understanding of the dynamic physical, chemical and biological processes is strongly dependent on our ability to obtain uncontaminated samples from this challenging environment. Recent technological advances have addressed some, but certainly not all of these sampling problems, providing new data and samples that test our current hypotheses about the crustal fluid reservoir. Current scientific interest in the sub‐seafloor biosphere has focused on the uppermost igneous oceanic crust as likely to be one of the most habitable environments, because of its porosity and locus of hydrothermal circulation of chemical nutrients. Recent observations indicate that sub‐seafloor crustal environments harbor novel CO2‐utilizing bacteria (primary producers) that could be a significant source of carbon‐fixation in the ocean, thus broadening possible habitable zones both on Earth and elsewhere where microbial life could exist independent of nutrient input from photosynthesis.