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Evolutionary History (evolutionary + history)
Kinds of Evolutionary History Selected AbstractsTHE EVOLUTIONARY HISTORY OF MYCORRHIZAL SPECIFICITY AMONG LADY'S SLIPPER ORCHIDSEVOLUTION, Issue 6 2007Richard P. Shefferson Although coevolution is acknowledged to occur in nature, coevolutionary patterns in symbioses not involving species-to-species relationships are poorly understood. Mycorrhizal plants are thought to be too generalist to coevolve with their symbiotic fungi; yet some plants, including some orchids, exhibit strikingly narrow mycorrhizal specificity. Here, we assess the evolutionary history of mycorrhizal specificity in the lady's slipper orchid genus, Cypripedium. We sampled 90 populations of 15 taxa across three continents, using DNA methods to identify fungal symbionts and quantify mycorrhizal specificity. We assessed phylogenetic relationships among sampled Cypripedium taxa, onto which we mapped mycorrhizal specificity. Cypripedium taxa associated almost exclusively with fungi within family Tulasnellaceae. Ancestral specificity appears to have been narrow, followed by a broadening after the divergence of C. debile. Specificity then narrowed, resulting in strikingly narrow specificity in most of the taxa in this study, with no taxon rewidening to the same extant as basal members of the genus. Sympatric taxa generally associated with different sets of fungi, and most clades of Cypripedium -mycorrhizal fungi were found throughout much of the northern hemisphere, suggesting that these evolutionary patterns in specificity are not the result of biogeographic lack of opportunity to associate with potential partners. Mycorrhizal specificity in genus Cypripedium appears to be an evolvable trait, and associations with particular fungi are phylogenetically conserved. [source] DIATOMS: A COMPLEX EVOLUTIONARY HISTORY BECOMES EVEN MORE COMPLEXJOURNAL OF PHYCOLOGY, Issue 1 2003Klaus V. Kowallik No abstract is available for this article. [source] Different Evolutionary Histories of the Coagulation Factor VII Gene in Human Populations?ANNALS OF HUMAN GENETICS, Issue 1 2010Georgios Athanasiadis Summary Immoderate blood clotting constitutes a risk factor for cardiovascular disease in modern industrialised societies, but is believed to have conferred a survival advantage, i.e. faster recovery from bleeding, on our ancestors. Here, we investigate the evolutionary history of the Coagulation Factor VII gene (F7) by analysing five cardiovascular-risk-associated mutations from the F7 promoter and nine neutral polymorphisms (six SNPs and three microsatellites) from the flanking region in 16 populations from the broader Mediterranean region, South Saharan Africa and Bolivia (687 individuals in total). Population differentiation and selection tests were performed and linkage disequilibrium patterns were investigated. In all samples, no linkage disequilibrium between adjacent F7 promoter mutations ,402 and ,401 was observed. No selection signals were detected in any of the samples from the broader Mediterranean region and South Saharan Africa, while some of the data suggested a potential signal of positive selection for the F7 promoter in the Native American samples from Bolivia. In conclusion, our data suggest, although do not prove, different evolutionary histories in the F7 promoter region between Mediterraneans and Amerindians. [source] Discovery and Evolutionary History of Gonadotrophin-Inhibitory Hormone and Kisspeptin: New Key Neuropeptides Controlling ReproductionJOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2010K. Tsutsui Gonadotrophin-releasing hormone (GnRH) is the primary hypothalamic factor responsible for the control of gonadotrophin secretion in vertebrates. However, within the last decade, two other hypothalamic neuropeptides have been found to play key roles in the control of reproductive functions: gonadotrophin-inhibitory hormone (GnIH) and kisspeptin. In 2000, we discovered GnIH in the quail hypothalamus. GnIH inhibits gonadotrophin synthesis and release in birds through actions on GnRH neurones and gonadotrophs, mediated via GPR147. Subsequently, GnIH orthologues were identified in other vertebrate species from fish to humans. As in birds, mammalian and fish GnIH orthologues inhibit gonadotrophin release, indicating a conserved role for this neuropeptide in the control of the hypothalamic-pituitary-gonadal axis across species. Subsequent to the discovery of GnIH, kisspeptin, encoded by the KiSS-1 gene, was discovered in mammals. By contrast to GnIH, kisspeptin has a direct stimulatory effect on GnRH neurones via GPR54. GPR54 is also expressed in pituitary cells, but whether gonadotrophs are targets for kisspeptin remains unresolved. The KiSS-1 gene is also highly conserved and has been identified in mammals, amphibians and fish. We have recently found a second isoform of KiSS-1, designated KiSS-2, in several vertebrates, but not birds, rodents or primates. In this review, we highlight the discovery, mechanisms of action, and functional significance of these two chief regulators of the reproductive axis. [source] SYNTHESIS: Evolutionary history of Pacific salmon in dynamic environmentsEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 2 2008Robin S. Waples Abstract Contemporary evolution of Pacific salmon (Oncorhynchus spp.) is best viewed in the context of the evolutionary history of the species and the dynamic ecosystems they inhabit. Speciation was complete by the late Miocene, leaving c. six million years for intraspecific diversification. Following the most recent glacial maximum, large areas became available for recolonization. Current intraspecific diversity is thus the product of recent evolution overlaid onto divergent historical lineages forged during recurrent episodes of Pleistocene glaciation. In northwestern North America, dominant habitat features have been relatively stable for the past 5000 years, but salmon ecosystems remain dynamic because of disturbance regimes (volcanic eruptions, landslides, wildfires, floods, variations in marine and freshwater productivity) that occur on a variety of temporal and spatial scales. These disturbances both create selective pressures for adaptive responses by salmon and inhibit long-term divergence by periodically extirpating local populations and creating episodic dispersal events that erode emerging differences. Recent anthropogenic changes are replicated pervasively across the landscape and interrupt processes that allow natural habitat recovery. If anthropogenic changes can be shaped to produce disturbance regimes that more closely mimic (in both space and time) those under which the species evolved, Pacific salmon should be well-equipped to deal with future challenges, just as they have throughout their evolutionary history. [source] The Biological Path to ReunificationGERMAN RESEARCH, Issue 2-3 2002William Martin Prof. The familiar form of the family tree is not applicable to all living organisms. Evolutionary history entails not only the divergence of lineages, but also mergers of distinct unicellular organisms (prokaryotes and protists) to form new cell types [source] Evolutionary history shapes the association between developmental instability and population-level genetic variation in three-spined sticklebacksJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 8 2009S. VAN DONGEN Abstract Developmental instability (DI) is the sensitivity of a developing trait to random noise and can be measured by degrees of directionally random asymmetry [fluctuating asymmetry (FA)]. FA has been shown to increase with loss of genetic variation and inbreeding as measures of genetic stress, but associations vary among studies. Directional selection and evolutionary change of traits have been hypothesized to increase the average levels of FA of these traits and to increase the association strength between FA and population-level genetic variation. We test these two hypotheses in three-spined stickleback (Gasterosteus aculeatus L.) populations that recently colonized the freshwater habitat. Some traits, like lateral bone plates, length of the pelvic spine, frontal gill rakers and eye size, evolved in response to selection regimes during colonization. Other traits, like distal gill rakers and number of pelvic fin rays, did not show such phenotypic shifts. Contrary to a priori predictions, average FA did not systematically increase in traits that were under presumed directional selection, and the increases observed in a few traits were likely to be attributable to other factors. However, traits under directional selection did show a weak but significantly stronger negative association between FA and selectively neutral genetic variation at the population level compared with the traits that did not show an evolutionary change during colonization. These results support our second prediction, providing evidence that selection history can shape associations between DI and population-level genetic variation at neutral markers, which potentially reflect genetic stress. We argue that this might explain at least some of the observed heterogeneities in the patterns of asymmetry. [source] Evolutionary history of lamprey paired species Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) as inferred from mitochondrial DNA variationMOLECULAR ECOLOGY, Issue 9 2007RUTE ESPANHOL Abstract A remarkable trend in the evolution of lampreys is the occurrence in most genera of ,paired species', in which the parasitic anadromous lampreys are believed to have given rise to nonparasitic freshwater resident populations. The present work examines the phylogeography of the European paired species Lampetra fluviatilis and Lampetra planeri, in an attempt to elucidate species pair evolutionary history. We studied sequence variation in cytochrome b and ATPase 6, 8 mitochondrial genes in 63 individuals from 21 localities of the paired species throughout their distribution range. Results from the phylogenetic and nested clade analyses were largely consistent, suggesting the existence of three major evolutionary lineages: lineage I and possibly lineage II are widespread throughout Europe, while the most ancestral lineage III is apparently restricted to the Iberian Peninsula. The high genetic diversity observed in the Iberian Peninsula is probably the result of refugial persistence and subsequent accumulation of variation over several ice ages, whereas the low levels of genetic diversity observed in central and northern Europe should reflect a rapid postglacial colonization. Results suggest that L. planeri originated within at least two distinct evolutionary lineages, rejecting the single origin hypothesis. The observed lack of taxa monophyly within lineage I may be the result of ongoing gene flow if the two taxa are alternate life-history forms of a single species. However, structure within lineage I is also consistent with the hypothesis of divergence of taxa after postglacial dispersion (around 2000 generations ago) with incomplete lineage sorting. Further testing of the alternative hypotheses is warranted. [source] Evolutionary history of the European whitefish Coregonus lavaretus (L.) species complex as inferred from mtDNA phylogeography and gill-raker numbersMOLECULAR ECOLOGY, Issue 14 2005K. ØSTBYE Abstract We compared mitochondrial DNA and gill-raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on gill-raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500,5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of gill-raker variation. Whitefish designations based on gill-raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered. [source] Evolutionary history of the land snail Helix aspersa in the Western Mediterranean: preliminary results inferred from mitochondrial DNA sequencesMOLECULAR ECOLOGY, Issue 1 2001A. Guiller Abstract Intraspecific phylogeographic methods provide a means of examining the history of genetic exchange among populations. As part of a study of the history of Helixaspersa in the Western Mediterranean, we performed a phylogenetic analysis based on partial sequences of the mitochondrial large ribosomal subunit (16S) gene. Our samples include 31 H. a. aspersa populations from North Africa previously investigated for anatomical and biochemical characters. To clarify subspecific relationships, three individuals of the subspecies H. a. maxima were also studied. The molecular phylogeny inferred agrees largely with previous results, in splitting H. a. aspersa haplotypes into an eastern and a western group. H. a. maxima haplotypes form a third lineage arising before the H. a.aspersa groups. Divergence times estimated between the lineages suggest that dispersal during Pleistocene glaciation and vicariance events due to Pliocene geological changes in the western Mediterranean may both have played a significant part in the establishment of the present range of H. aspersa. [source] Evolutionary history of the ancient cutinase family in five filamentous Ascomycetes reveals differential gene duplications and losses and in Magnaporthe grisea shows evidence of sub- and neo-functionalizationNEW PHYTOLOGIST, Issue 3 2008Pari Skamnioti Summary ,,The cuticle is the first barrier for fungi that parasitize plants systematically or opportunistically. Here, the evolutionary history is reported of the multimembered cutinase families of the plant pathogenic Ascomycetes Magnaporthe grisea, Fusarium graminearum and Botrytis cinerea and the saprotrophic Ascomycetes Aspergillus nidulans and Neurospora crassa. ,,Molecular taxonomy of all fungal cutinases demonstrates a clear division into two ancient subfamilies. No evidence was found for lateral gene transfer from prokaryotes. The cutinases in the five Ascomycetes show significant copy number variation, they form six clades and their extreme sequence diversity is highlighted by the lack of consensus intron. The average ratio of gene duplication to loss is 2 : 3, with the exception of M. grisea and N. crassa, which exhibit extreme family expansion and contraction, respectively. ,,Detailed transcript profiling in vivo, categorizes the M. grisea cutinases into four regulatory patterns. Symmetric or asymmetric expression profiles of phylogenetically related cutinase genes suggest subfunctionalization and neofunctionalization, respectively. ,,The cutinase family-size per fungal species is discussed in relation to genome characteristics and lifestyle. The ancestry of the cutinase gene family, together with the expression divergence of its individual members provides a first insight into the drivers for niche differentiation in fungi. [source] Evolutionary history of vertebrate appendicular muscleBIOESSAYS, Issue 5 2001Frietson Galis The evolutionary history of muscle development in the paired fins of teleost fish and the limbs of tetrapod vertebrates is still, to a large extent, uncertain. There has been a consensus, however, that in the vertebrate clade the ancestral mechanism of fin and limb muscle development involves the extension of epithelial tissues from the somite into the fin/limb bud. This mechanism has been documented in chondrichthyan, dipnoan, chondrostean and teleost fishes. It has also been assumed that in amniotes, in contrast, individual progenitor cells of muscles migrate from the somites into the limb buds. Neyt et al.(1) now present the exciting finding that in zebrafishes this presumably derived mechanism involving individual cell migration, is present. They conclude, based on data on sharks, zebrafishes, chickens, quails and mice that the derived mechanism was present in the sarcopterygians. This conclusion, however, may be premature in the light of further data available in the literature, which show a highly mosaic distribution of this character in the vertebrate clade. Furthermore, a developmental mode exists that is intermediate between the supposed ancestral and derived modes in teleosts, reptiles and possibly amphibians. BioEssays 23:383,387, 2001. © 2001 John Wiley & Sons, Inc. [source] Evolutionary history of the bank vole Myodes glareolus: a morphometric perspectiveBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010RONAN LEDEVIN The bank vole experienced a complex history during the Quaternary. Repeated isolation in glacial refugia led to the differentiation of several lineages in less than 300 000 years. We investigated if such a recent differentiation led to a significant divergence of phenotypic characters between European lineages, which might provide insight into processes of intraspecific differentiation. The size and shape of the first and third upper molars, and first lower molar, of bank voles genetically attributed to different lineages were quantified using an outline analysis of their occlusal surface. The three teeth present similar trends of decreasing size towards high latitudes. This trend, the inverse of Bergmann's rule, is interpreted as the result of a balance between metabolic efficiency and food availability, favouring small body size in cold regions. Molar shape appeared to differ between lineages despite genetic evidence of suture zones. A mosaic pattern of evolution between the different teeth was evidenced. The analysis of such phenotypic features appears as a valuable complement to genetic analyses, providing a complementary insight into evolutionary processes, such as selective pressures, that have driven the differentiation of the lineages. It may further allow the integration of the paleontological dimension of the bank vole phylogeographic history. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 681,694. [source] Taxonomy, evolutionary History and Distribution of the middle to late Famennian Wocklumeriina (Ammonoidea, Clymeniida)FOSSIL RECORD-MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE, Issue 1 2000R. Thomas Becker Abstract Old collections, new records, and data from global literature are used for taxonomic revisions and for a new reconstruction of the evolutionary history of the triangularly coiled clymenids, the Wocklumeriaceae, and their ancestors. Epiwocklumeria applanata is first reported from the topmost Wocklum Limestone at Hasselbachtal and Drewer, and this supports the distinction of an applanata Subzone just prior to the global Hangenberg Event which wiped out the whole group. The Wocklumeriaceae and Glatziellidae record of the famous Oberrödinghausen Railway Cut and of other Rhenish sections is revised. The Maïder of Southern Morocco has yielded first Parawocklumeria patens, paprothae, Wocklumeria sphaeroides plana, Kielcensia ingeniens n. sp., and Synwocklumeria mapesi n. sp. Parawocklumeria distributa Czarnocki forms the type-species of Tardewocklumeria n. gen. Lecto- and neotypes for several taxa are designated. The variability and paedomorphic patterns of Wo. sphaeroides are discussed. The Wocklumeriaceae represent the terminal Famennian (Upper Devonian VI-C/D) radiation of a long-ranging lineage which evolved in parallel to other clymenid groups. They are characterized by sutural features and by longidomic and very slowly expanding whorls. The polyphyletic traditional Gonioclymeniina are divided into the suborder Wocklumeriina (with Wocklumeriaceae, Glatziellaceae n.superfam. and Biloclymeniaceae) and into the Gonioclymeniaceae of the Clymeniina. Gyroclymenia Czarnocki is regarded as a junior synonym of Pleuroclymenia Schindewolf which, however, does not include the ,Pleuro.' americana and eurylobica groups. Pleuroclymenia represents the ancestral form of the Wocklumeriina and also the phylogenetical link with Platyclymenia (Varioclymenia) of the Clymeniaceae. The Gonioclymeniaceae had their roots in advanced Platyclymeniidae. Alte Aufsammlungen, Neunachweise und globale Literaturdaten werden für taxonomische Revisionen und für eine neue Rekonstruktion der Evolution der Dreiecksclymenien (Wocklumeriaceae) und ihrer Vorfahren benutzt. Epiwocklumeria applanata wird zum ersten Mal im Hasselbachtal und bei Drewer nachgewiesen, und diese Funde bestätigen die Abtrennung einer applanata -Subzone im unmittelbar Liegenden des Hangenberg-Event, welcher zum Aussterben der gesamten Gruppe führte. Die Verbreitung von Wocklumeriaceae und Glatziellidae im klassischen Profil des Bahneinschnittes bei Oberrödinghausen und an anderen Fundorten im Rheinischen Schiefergebirge wird revidiert. Der Maïder in Süd-Marokko lieferte erstmalig Parawocklumeria patens, paprothae, Wocklumeria sphaeroides plana, Kielcensia ingeniens n. sp. und Synwocklumeria mapesi n. sp. Parawocklumeria distributa Czarnocki bildet die Typus-Art von Tardewocklumeria n.gen. Weiterhin werden die Variabilität und paedomorphe Erscheinungen bei Wo. sphaeroides diskutiert. Die Wocklumeriaceae repräsentieren im höchsten Famennium (UD VI-C/D) die Radiationsphase einer langlebigen phylogenetischen Linie, die sich parallel zu anderen Clymenien entwickelte. Sie ist durch Suturmerkmale und lange Wohnkammern bei niedrigmündigen Gehäusen charakterisiert. Die als polyphyletisch erkannten Gonioclymeniina werden in die Wocklumeriina (mit Wocklumeriaceae, Glatziellaceae n.superfam. und Biloclymeniaceae) und in die Gonioclymeniaceae der Clymeniina geteilt. Gyroclymenia Czarnocki ist ein jüngeres Synonym von Pleuroclymenia Schindewolf, umfasst jedoch nicht die ,Pleuro.' americana -und ,Pleuro.' eurylobica -Artgruppen. Die Gattung ist die ursprünglichste Form der Wocklumeriina und stellt gleichzeitig das Bindeglied zu Platyclymenia (Varioclymenia) der Clymeniaceae dar. Die Gonioclymeniaceae wurzeln in fortgeschrittenen Platyclymeniidae. [source] Quantitative analysis of InSAR digital elevation models for identification of areas with different tectonic activities in southern ItalyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 1 2009Claudio Martino Abstract This work presents the results of a quantitative analysis of an interferometric SAR (InSAR) digital elevation model (DEM), obtained by the Shuttle Radar Topography Mission (SRTM). The analysis aims to identify additional parameters to recognize areas in southern Italy with different tectonic activities and behaviours. The axial zone of the Campania-Lucania Apennine and the Sila Massif in Calabria, Italy, characterized by quite different evolutionary histories, have been chosen as test areas sufficiently wide to validate observations on a sub-regional scale at least. Geomorphological information on the shape of palaeosurfaces has been used to estimate uplift and/or erosion amounts and rates. Palaeosurfaces are identified on the DEM as regions with an altitude higher than 1000 m a.s.l. and sub-planar land surfaces dipping less than 6°. Information about the shape of palaeosurfaces during the first stage of uplift and before the tectonic-induced block fragmentation has been extracted. A fragmentation index has been computed for these erosional surfaces. The first stage of this landscape evolution has been studied in terms of the geometric characteristics of fragmented blocks. The last erosional stage has been recognized in terms of both geometric characteristics and fragmentation index of the sub-horizontal land surfaces. Altitude and age of the palaeosurfaces, referred to ancient base-levels of the erosion, have been used to estimate the erosional rate. Copyright © 2008 John Wiley and Sons, Ltd. [source] The island rule and a research agenda for studying ecogeographical patternsJOURNAL OF BIOGEOGRAPHY, Issue 9 2006Mark V. Lomolino Abstract We are currently experiencing a resurgence of interest in ecogeographical rules, which describe general trends in morphology and related traits along geographical gradients. In order to develop a more comprehensive understanding of the generality and underlying causal mechanisms for these patterns, we recommend a new, more integrated research agenda. In particular, we recommend studies that simultaneously consider different clines in morphology, geographical ranges and diversity as intricately related phenomena; all being ecological, evolutionary and biogeographical responses of organisms to selection regimes that vary non-randomly over space and time, and among species with different ecological and evolutionary histories. [source] Spatial analysis of taxonomic and genetic patterns and their potential for understanding evolutionary historiesJOURNAL OF BIOGEOGRAPHY, Issue 11 2004Sophia A. Bickford Abstract Aim, The aim of this research is to develop and investigate methods for the spatial analysis of diversity based on genetic and taxonomic units of difference. We use monophyletic groups of species to assess the potential for these diversity indices to elucidate the geographical components of macro-scaled evolutionary processes. Location, The range occupied by Pultenaea species in temperate and sub-tropical eastern Australia, extending from western South Australia (133° E,32° S) to Tasmania (146° E,43° S) to coastal central Queensland (148° E,20° S). Methods, We applied a series of both spatially explicit and spatially implicit analyses to explore the nature of diversity patterns in the genus Pultenaea, Fabaceae. We first analysed the eastern species as a whole and then the phylogenetic groups within them. We delineated patterns of endemism and biotic (taxon) regions that have been traditionally circumscribed in biogeographical studies of taxa. Centres of endemism were calculated using corrected weighted endemism at a range of spatial scales. Biotic regions were defined by comparing the similarity of species assemblages of grid cells using the Jaccard index and clustering similar cells using hierarchical clustering. On the basis that genetically coherent areas were likely to be more evolutionary informative than species patterns, genetic indices of similarity and difference were derived. A matrix of similarity distances between taxa was generated based on the number of shared informative characters of two sections of trnL-F and ndhF chloroplast nuclear regions. To identify genetically similar areas, we clustered cells using the mean genetic similarities of the species contained within each pair of cells. Measures of the mean genetic similarity of species in areas were delineated using a geographically local multi-scalar approach. Resultant patterns of genetic diversity are interpreted in relation to theories of the evolutionary relationships between species and species groups. Results, Centres of Pultenaea endemism were defined, those of clades 1 congruent with the spatially separated centres of clades 2 and 3. The taxonomic classification analysis defined cells with shared groups of species, which in some cases clustered when plotted in geographic space, defining biotic regions. In some instances the distribution of biotic regions was congruent with centres of endemism, however larger scale groupings were also apparent. In clade 1 one set of species was replaced by another along the extent of the range, with some connectivity between some geographically disjunct regions due to the presence of widespread species. In the combined analysis of clade 2 and 3 species the major biotic (taxonomic) groups with geographic coherence were defined by species in the respective clades, representing the geographic separation of these clades. However distinctive biotic regions within these main groupings of clades 2 and 3 were also apparent. Clustering cells using the mean genetic similarities of the species contained within each pair of cells indicated that some of the taxonomically defined biotic boundaries were the result of changes in composition of closely related species. This was most apparent in clades 1 and 2 where most cells were highly genetically similar. In clade 3 genetically distinct groups remained and were in part defined by sister taxa with disjunct distributions. Gradients in mean genetic similarity became more apparent from small to larger scales of analysis. At larger scales of analysis, regions of different levels of genetic diversity were delineated. Regions with highest diversity levels (lowest level of similarity) often represented regions where the ranges of phylogenetically distinctive species intergraded. Main conclusions, The combined analysis of diversity, phylogeny and geography has potential to reveal macro-scaled evolutionary patterns from which evolutionary processes may be inferred. The spatial genetic diversity indices developed in this study contribute new methods for identifying coherent evolutionary units in the landscape, which overcome some of the limitations of using taxonomic data, and from which the role of geography in evolutionary processes can be tested. We also conclude that a multiple-index approach to diversity pattern analysis is useful, especially where patterns may be the result of a long history of different environmental changes and related evolutionary events. The analysis contributes to the knowledge of large-scale diversity patterns of Pultenaea which has relevance for the assessment of the conservation status of the genus. [source] Limb morphogenesis in the branchiopod crustacean, Thamnocephalus platyurus, and the evolution of proximal limb lobes within AnostracaJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2007T. A. Williams Abstract Crustacean limbs exhibit highly diverse morphologies. One major route of diversification is in the number and position of branches arising from the proximal part of the limb. Here I describe development of larvae of the branchiopod crustacean, Thamnocephalus platyurus and describe in detail the development of the thoracic limbs. The thoracic limbs bear proximal branches both medially and laterally. The most proximal branches on either side (gnathobase and pre-epipod) show a similar developmental history: they develop via fusion of two rudiments into a single adult branch. However, phylogenetic analysis suggests that the developmental fusions have distinct evolutionary histories. In one case (gnathobase), the developmental rudiments reflect the ancestral adult morphology of two distinct branches. In the other (pre-epipod), the rudiments are an apparent novelty within the Anostraca and develop into two adult structures in only a single derived family. Zusammenfassung Die Extremitäten von Krebsen zeigen eine Vielfalt an unterschiedlichen Morphologien. Diversifikation findet zum Grossteil über Anzahl und Position der aus dem proximalen Anteil der Extremitäten entspringenden Äste statt. In dieser Studie wird die Larvalentwicklung von Thamnocephalus platyurus, einem branchiopoden Krebs, beschrieben, vor allem die Entwicklung der Extremitäten der Thoracalsegmente. Diese tragen proximale Äste, sowohl medial, als auch lateral. Die proximalsten Äste beider Seiten (Gnathobasis und Praeepipodit) zeigen ähnliche Entwicklungen: Beide entstehen durch Fusion zweier Rudimente zu einem einzigen Ast im Adultstadium. Phylogenetische Analysen lassen darauf schließen, dass diese Fusionen während der Entwicklung unabhängig entstanden sind. In einem Fall (Gnathobasis) spiegeln die Rudimente im Entwicklungsstadium die ancestrale adulte Morphologie zweier unterschiedlicher Äste wieder. Im anderen Fall (Praeepipodit) sind die Rudimente vermutlich Innovationen innerhalb der Anostraca und entwickeln sich zu zwei verschiedenen Strukturen in nur einer einzigen Familie. [source] Molluscan muscle systems in development and evolution,JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2000G. Haszprunar The evolutionary history of the various molluscan muscle systems reflects drastic modifications and reductions as well as true innovations. No less than eight main and independent muscle systems of the Mollusca are described and, based on the current understanding of molluscan phylogeny, their evolutionary histories are outlined.New data on the myogenesis of the Polyplacophora by means of fluorescence-staining and image analysis by confocal laser scanning microscopy show that the pre-oral region recapitulates a ,worm-grid', and that the dorso-ventral musculature passes a stage of multiple seriality as found in adult Solenogastres. Old and new data on bivalves and recent studies on primitive gastropods provide clear evidence that the larval musculature of both groups (and thus possibly of all conchiferans) is entirely independent from the adult condition. The growth of shell-inserted muscles always necessitates substantial renewal of myocytes which is still poorly understood. Although very promising for phylogenetic purposes, the understanding of the developmental genetics of the various molluscan muscle systems is still in its infancy. [source] Tutorial on Computational Linguistic PhylogenyLINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 5 2008Johanna Nichols Over the last 10 or more years, there has been a tremendous increase in the use of computational techniques (many of which come directly from biology) for estimating evolutionary histories (i.e., phylogenies) of languages. This tutorial surveys the different methods and different types of linguistic data that have been used to estimate phylogenies, explains the scientific and mathematical foundations of phylogenetic estimation, and presents methodologies for evaluating a phylogeny estimation method. [source] The discordance of diversification: evolution in the tropical-montane frogs of the Eastern Arc Mountains of TanzaniaMOLECULAR ECOLOGY, Issue 18 2010LUCINDA P. LAWSON Abstract Species with similar geographical distribution patterns are often assumed to have a shared biogeographical history, an assumption that can be tested with a combination of molecular, spatial, and environmental data. This study investigates three lineages of Hyperolius frogs with concordant ranges within the Eastern Afromontane Biodiversity Hotspot to determine whether allopatric populations of co-distributed lineages shared a parallel biogeographical response to their shared paleoclimatic histories. The roles of refugial distributions, isolation, and climate cycles in shaping their histories are examined through Hierarchical Approximate Bayesian Computation, comparative phylogeography, and comparisons of current and past geographical distributions using ecological niche models. Results from these analyses show these three lineages to have independent evolutionary histories, which current spatial configurations of sparsely available habitat (montane wetlands) have moulded into convergent geographical ranges. In spite of independent phylogeographical histories, diversification events are temporally concentrated, implying that past vicariant events were significant at the generic level. This mixture of apparently disparate histories is likely due to quantifiably different patterns of expansion and retreat among species in response to past climate cycles. Combining climate modelling and phylogeographical data can reveal unrecognized complexities in the evolution of co-distributed taxa. [source] Finding a (pine) needle in a haystack: chloroplast genome sequence divergence in rare and widespread pinesMOLECULAR ECOLOGY, Issue 2010J. B. WHITTALL Abstract Critical to conservation efforts and other investigations at low taxonomic levels, DNA sequence data offer important insights into the distinctiveness, biogeographic partitioning and evolutionary histories of species. The resolving power of DNA sequences is often limited by insufficient variability at the intraspecific level. This is particularly true of studies involving plant organelles, as the conservative mutation rate of chloroplasts and mitochondria makes it difficult to detect polymorphisms necessary to track genealogical relationships among individuals, populations and closely related taxa, through space and time. Massively parallel sequencing (MPS) makes it possible to acquire entire organelle genome sequences to identify cryptic variation that would be difficult to detect otherwise. We are using MPS to evaluate intraspecific chloroplast-level divergence across biogeographic boundaries in narrowly endemic and widespread species of Pinus. We focus on one of the world's rarest pines , Torrey pine (Pinus torreyana) , due to its conservation interest and because it provides a marked contrast to more widespread pine species. Detailed analysis of nearly 90% (,105 000 bp each) of these chloroplast genomes shows that mainland and island populations of Torrey pine differ at five sites in their plastome, with the differences fixed between populations. This is an exceptionally low level of divergence (1 polymorphism/,21 kb), yet it is comparable to intraspecific divergence present in widespread pine species and species complexes. Population-level organelle genome sequencing offers new vistas into the timing and magnitude of divergence within species, and is certain to provide greater insight into pollen dispersal, migration patterns and evolutionary dynamics in plants. [source] Extreme population subdivision throughout a continuous range: phylogeography of Batrachoseps attenuatus (Caudata: Plethodontidae) in western North AmericaMOLECULAR ECOLOGY, Issue 20 2007IÑIGO MARTÍNEZ, SOLANO Abstract Low-vagility species with deep evolutionary histories are key to our understanding of the biogeographical history of geologically complex areas, such as the west coast of North America. We present a detailed study of the phylogeography of the salamander Batrachoseps attenuatus (Caudata: Plethodontidae) using sequences of the mitochondrial gene cob from 178 individuals sampled from throughout the species' range. Sequences of three other mitochondrial genes (16S, cox1, nad4) and a nuclear gene (RAG-1) were used to investigate the deeper evolutionary history of the species. We found high levels of genetic diversity and deep divergences within a mostly continuous distribution, with five genetically well-differentiated and geographically structured mitochondrial DNA clades. Significant association between geographical and genetic distances within these clades suggests demographic stability, whereas Fu's FS tests suggest demographic expansions in three of them. Mantel tests identify two biogeographical barriers, the San Andreas Fault and the Sacramento,San Joaquin Delta, as important in the diversification of lineages. The timing of the main splitting events between intraspecific lineages was estimated by applying relaxed molecular clock methods combining several mutation rates and a fossil calibration. The earliest splitting events are old (Pliocene/Miocene), with more recent (Pleistocene) subdivisions in some clades. Disjunct populations distributed along the western foothills of the Sierra Nevada colonized this area relatively recently from a single refugium east of San Francisco Bay. The combination of fine-scale, comprehensive sampling with phylogenetic, historical demographic and hypothesis-based tests allowed delineation of a complex biogeographical scenario with general implications for the study of codistributed taxa. [source] A Signal for Independent Coastal and Continental histories among North American wolvesMOLECULAR ECOLOGY, Issue 4 2005BYRON V. WECKWORTH Abstract Relatively little genetic variation has been uncovered in surveys across North American wolf populations. Pacific Northwest coastal wolves, in particular, have never been analysed. With an emphasis on coastal Alaska wolf populations, variation at 11 microsatellite loci was assessed. Coastal wolf populations were distinctive from continental wolves and high levels of diversity were found within this isolated and relatively small geographical region. Significant genetic structure within southeast Alaska relative to other populations in the Pacific Northwest, and lack of significant correlation between genetic and geographical distances suggest that differentiation of southeast Alaska wolves may be caused by barriers to gene flow, rather than isolation by distance. Morphological research also suggests that coastal wolves differ from continental populations. A series of studies of other mammals in the region also has uncovered distinctive evolutionary histories and high levels of endemism along the Pacific coast. Divergence of these coastal wolves is consistent with the unique phylogeographical history of the biota of this region and re-emphasizes the need for continued exploration of this biota to lay a framework for thoughtful management of southeast Alaska. [source] Evolutionary and statistical properties of three genetic distancesMOLECULAR ECOLOGY, Issue 8 2002Steven T. Kalinowski Abstract Many genetic distances have been developed to summarize allele frequency differences between populations. I review the evolutionary and statistical properties of three popular genetic distances: DS, DA, and ,, using computer simulation of two simple evolutionary histories: an isolation model of population divergence and an equilibrium migration model. The effect of effective population size, mutation rate, and mutation mechanism upon the parametric value between pairs of populations in these models explored, and the unique properties of each distance are described. The effect of these evolutionary parameters on study design is also investigated and similar results are found for each genetic distance in each model of evolution: large sample sizes are warranted when populations are relatively genetically similar; and loci with more alleles produce better estimates of genetic distance. [source] Comparative phylogeography of sympatric sister species, Clevelandia ios and Eucyclogobius newberryi (Teleostei, Gobiidae), across the California Transition ZoneMOLECULAR ECOLOGY, Issue 6 2002M. N Dawson Abstract It is paradigmatic in marine species that greater dispersal ability often, but not always, results in greater gene flow and less population structure. Some of the exceptions may be attributable to studies confounded by comparison of species with dissimilar evolutionary histories, i.e. co-occurring species that are not closely related or species that are closely related but allopatric. Investigation of sympatric sister species, in contrast, should allow differences in phylogeographic structure to be attributed reliably to recently derived differences in dispersal ability. Here, using mitochondrial DNA control region sequence, we first confirm that Clevelandia ios and Eucyclogobius newberryi are sympatric sister taxa, then demonstrate considerably shallower phylogeographic structure in C. ios than in E. newberryi. This shallower phylogeographic structure is consistent with the higher dispersal ability of C. ios, which most likely results from the interaction of habitat and life-history differences between the species. We suggest that the paradigm will be investigated most rigorously by similar studies of other sympatric sister species, appended by thorough ecological studies, and by extending this sister-taxon approach to comparative phylogeographic studies of monophyletic clades of sympatric species. [source] Variability patterns and positively selected sites at the gametophytic self-incompatibility pollen SFB gene in a wild self-incompatible Prunus spinosa (Rosaceae) populationNEW PHYTOLOGIST, Issue 3 2006Maria D. S. Nunes Summary ,,Current models for the generation of new gametophytic self-incompatibility specificities require that neutral variability segregates within specificity classes. Furthermore, one of the models predicts greater ratios of nonsynonymous to synonymous substitutions in pollen than in pistil specificity genes. All models assume that new specificities arise by mutation only. ,,To test these models, 21 SFB (the pollen S -locus) alleles from a wild Prunus spinosa (Rosaceae) population were obtained. For seven of these, the corresponding S -haplotype was also characterized. The SFB data set was also used to identify positively selected sites. Those sites are likely to be the ones responsible for defining pollen specificities. ,,Of the 23 sites identified as being positively selected, 21 are located in the variable (including a new region described here) and hypervariable regions. Little variability is found within specificity classes. There is no evidence for selective sweeps being more frequent in pollen than in pistil specificity genes. The S-RNase and the SFB genes have only partially correlated evolutionary histories. ,,None of the models is compatible with the variability patterns found in the SFB and the S -haplotype data. [source] Different Evolutionary Histories of the Coagulation Factor VII Gene in Human Populations?ANNALS OF HUMAN GENETICS, Issue 1 2010Georgios Athanasiadis Summary Immoderate blood clotting constitutes a risk factor for cardiovascular disease in modern industrialised societies, but is believed to have conferred a survival advantage, i.e. faster recovery from bleeding, on our ancestors. Here, we investigate the evolutionary history of the Coagulation Factor VII gene (F7) by analysing five cardiovascular-risk-associated mutations from the F7 promoter and nine neutral polymorphisms (six SNPs and three microsatellites) from the flanking region in 16 populations from the broader Mediterranean region, South Saharan Africa and Bolivia (687 individuals in total). Population differentiation and selection tests were performed and linkage disequilibrium patterns were investigated. In all samples, no linkage disequilibrium between adjacent F7 promoter mutations ,402 and ,401 was observed. No selection signals were detected in any of the samples from the broader Mediterranean region and South Saharan Africa, while some of the data suggested a potential signal of positive selection for the F7 promoter in the Native American samples from Bolivia. In conclusion, our data suggest, although do not prove, different evolutionary histories in the F7 promoter region between Mediterraneans and Amerindians. [source] Complexity in small-scale dwarf spheroidal galaxies , Ludwig Biermann Award Lecture 2008ASTRONOMISCHE NACHRICHTEN, Issue 7 2009A. KochArticle first published online: 17 JUL 200 Abstract Our knowledge about the dynamics, the chemical abundances and the evolutionary histories of the more luminous dwarf spheroidal (dSph) galaxies is constantly growing. However, very little is known about the enrichment of the ultra-faint systems recently discovered in large numbers in large sky surveys. Current low-resolution spectroscopy and photometric data indicate that these galaxies are highly dark matter dominated and predominantly metal poor. On the other hand, recent high-resolution abundance analyses indicate that some dwarf galaxies experienced highly inhomogeneous chemical enrichment, where star formation proceeds locally on small scales. In this article, I will review the kinematic and chemical abundance information of the Milky Way satellite dSphs that is presently available from low- and high resolution spectroscopy. Moreover, some of the most peculiar element and inhomogeneous enrichment patterns will be discussed and related to the question of to what extent the faintest dSph candidates could have contributed to the Galactic halo, compared to more luminous systems (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ecological and evolutionary components of body size: geographic variation of venomous snakes at the global scaleBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009LEVI CARINA TERRIBILE Biogeographical patterns of animal body size and the environmental and evolutionary mechanisms that may be driving them have been broadly investigated in macroecology, although just barely in ectotherms. We separately studied two snake clades, Viperidae and Elapidae, and used phylogenetic eigenvector regression and ordinary least squares multiple regression methods to perform a global grid-based analysis of the extent at which the patterns of body size (measured for each species as its log10 -transformed maximum body length) of these groups are phylogenetically structured or driven by current environment trends. Phylogenetic relatedness explained 20% of the across-species size variation in Viperidae, and 59% of that of Elapidae, which is a more recent clade. Conversely, when we analysed spatial trends in mean body size values (calculated for each grid-cell as the average size of its extant species), an environmental model including temperature, precipitation, primary productivity (as indicated by the global vegetation index) and topography (range in elevation) explained 37.6% of the variation of Viperidae, but only 4.5% of that of Elapidae. These contrasted responses of body size patterns to current environment gradients are discussed, taking into consideration the dissimilar evolutionary histories of these closely-related groups. Additionally, the results obtained emphasize the importance of the need to start adopting deconstructive approaches in macroecology. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 94,109. [source] | ||||||||||||||||||||||||||||||||||||||||||||||