42,450 research outputs found
Adaptive variation and introgression of a CONSTANS-like gene in North American red oaks
No full textOaks provide a model system to study maintenance of species identity by divergent selection since they maintain morphological differences and ecological adaptations despite interspecific hybridization. The genome of closely related interfertile oak species was shown to be largely homogeneous, with a few genomic areas exhibiting high interspecific differentiation possibly as result of strong divergent selection. Previously, a genic microsatellite was identified as under strong divergent selection, being nearly fixed on alternative alleles in the two interfertile North American red oak species: Quercus rubra L. and Quercus ellipsoidalis E.J. Hill. Further genotyping in two other red oak species—Quercus velutina Lam. and Quercus coccinea Münchh.—revealed a similar bias for the Q. ellipsoidalis-specific allele. To further elucidate the basis of this differentiation, we sequenced the microsatellite in individuals from all four red oak species. Sequence variability was observed in the microsatellite motif which encodes a poly-Q repeat in a COL gene involved in phenology and growth. Furthermore, in neighboring (parapatric) Q. rubra/Q. ellipsoidalis populations, introgression of the Q. ellipsoidalis-specific allele into Q. rubra occurred at a lower rate than introgression of the Q. rubra-specific allele into Q. ellipsoidalis despite symmetric interspecific gene flow, indicating potential adaptive introgression. Introgression of adaptive alleles can be an important mechanism for rapid adaptation to new environmental conditions (e.g., climate change)
Evidence for selection on a CONSTANS-like gene between two red oak species
No full textBackground and Aims Hybridizing species such as oaks may provide a model to study the role of selection in speciation with gene flow. Discrete species\u27 identities and different adaptations are maintained among closely related oak species despite recurrent gene flow. This is probably due to ecologically mediated selection at a few key genes or genomic regions. Neutrality tests can be applied to identify so-called outlier loci, which demonstrate locus-specific signatures of divergent selection and are candidate genes for further study. Methods Thirty-six genic microsatellite markers, some with putative functions in flowering time and drought tolerance, and eight non-genic microsatellite markers were screened in two population pairs (n = 160) of the interfertile species Quercus rubra and Q. ellipsoidalis, which are characterized by contrasting adaptations to drought. Putative outliers were then tested in additional population pairs from two different geographic regions (n = 159) to support further their potential role in adaptive divergence. Key Results A marker located in the coding sequence of a putative CONSTANS-like (COL) gene was repeatedly identified as under strong divergent selection across all three geographically disjunct population pairs. COL genes are involved in the photoperiodic control of growth and development and are implicated in the regulation of flowering time. Conclusions The location of the polymorphism in the Quercus COL gene and given the potential role of COL genes in adaptive divergence and reproductive isolation makes this a promising candidate speciation gene. Further investigation of the phenological characteristics of both species and flowering time pathway genes is suggested in order to elucidate the importance of phenology genes for the maintenance of species integrity. Next-generation sequencing in multiple population pairs in combination with high-density genetic linkage maps could reveal the genome-wide distribution of outlier genes and their potential role in reproductive isolation between these species. © 2014 The Author
Hybridization, agency discretion, and implementation of the U.S. Endangered Species Act
No full textThe U.S. Endangered Species Act (ESA) requires that the “best available scientific and commercial data” be used to protect imperiled species from extinction and preserve biodiversity. However, it does not provide specific guidance on how to apply this mandate. Scientific data can be uncertain and controversial, particularly regarding species delineation and hybridization issues. The U.S. Fish and Wildlife Service (FWS) had an evolving hybrid policy to guide protection decisions for individuals of hybrid origin. Currently, this policy is in limbo because it resulted in several controversial conservation decisions in the past. Biologists from FWS must interpret and apply the best available science to their recommendations and likely use considerable discretion in making recommendations for what species to list, how to define those species, and how to recover them. We used semistructured interviews to collect data on FWS biologists’ use of discretion to make recommendations for listed species with hybridization issues. These biologists had a large amount of discretion to determine the best available science and how to interpret it but generally deferred to the scientific consensus on the taxonomic status of an organism. Respondents viewed hybridization primarily as a problem in the context of the ESA, although biologists who had experience with hybridization issues were more likely to describe it in more nuanced terms. Many interviewees expressed a desire to continue the current case-by-case approach for handling hybridization issues, but some wanted more guidance on procedures (i.e., a “flexible” hybrid policy). Field-level information can provide critical insight into which policies are working (or not working) and why. The FWS biologists’ we interviewed had a high level of discretion, which greatly influenced ESA implementation, particularly in the context of hybridization
GENETIC VARIATION, LOCAL ADAPTATION AND POPULATION STRUCTURE IN NORTH AMERICAN RED OAK SPECIES, QUERCUS RUBRA L. AND Q. ELLIPSOIDALIS E. J. HILL
No full textForest trees, like oaks, rely on high levels of genetic variation to adapt to varying environmental conditions. Thus, genetic variation and its distribution are important for the long-term survival and adaptability of oak populations. Climate change is projected to lead to increased drought and fire events as well as a northward migration of tree species, including oaks. Additionally, decline in oak regeneration has become increasingly concerning since it may lead to decreased gene flow and increased inbreeding levels. This will in turn lead to lowered levels of genetic diversity, negatively affecting the growth and survival of populations. At the same time, populations at the species’ distribution edge, like those in this study, could possess important stores of genetic diversity and adaptive potential, while also being vulnerable to climatic or anthropogenic changes. A survey of the level and distribution of genetic variation and identification of potentially adaptive genes is needed since adaptive genetic variation is essential for their long-term survival.
Oaks possess a remarkable characteristic in that they maintain their species identity and specific environmental adaptations despite their propensity to hybridize. Thus, in the face of interspecific gene flow, some areas of the genome remain differentiated due to selection. This characteristic allows the study of local environmental adaptation through genetic variation analyses. Furthermore, using genic markers with known putative functions makes it possible to link those differentiated markers to potential adaptive traits (e.g., flowering time, drought stress tolerance). Demographic processes like gene flow and genetic drift also play an important role in how genes (including adaptive genes) are maintained or spread. These processes are influenced by disturbances, both natural and anthropogenic. An examination of how genetic variation is geographically distributed can display how these genetic processes and geographical disturbances influence genetic variation patterns. For example, the spatial clustering of closely related trees could promote inbreeding with associated negative effects (inbreeding depression), if gene flow is limited. In turn this can have negative consequences for a species’ ability to adapt to changing environmental conditions. In contrast, interspecific hybridization may also allow the transfer of genes between species that increase their adaptive potential in a changing environment.
I have studied the ecologically divergent, interfertile red oaks, Quercus rubra and Q. ellipsoidalis, to identify genes with potential roles in adaptation to abiotic stress through traits such as drought tolerance and flowering time, and to assess the level and distribution of genetic variation. I found evidence for moderate gene flow between the two species and low interspecific genetic differences at most genetic markers (Lind and Gailing 2013). However, the screening of genic markers with potential roles in phenology and drought tolerance led to the identification of a CONSTANS-like (COL) gene, a candidate gene for flowering time and growth. This marker, located in the coding region of the gene, was highly differentiated between the two species in multiple geographical areas, despite interspecific gene flow, and may play a role in reproductive isolation and adaptive divergence between the two species (Lind-Riehl et al. 2014). Since climate change could result in a northward migration of trees species like oaks, this gene could be important in maintaining species identity despite increased contact zones between species (e.g., increased gene flow). Finally I examined differences in spatial genetic structure (SGS) and genetic variation between species and populations subjected to different management strategies and natural disturbances. Diverse management activities combined with various natural disturbances as well as species specific life history traits influenced SGS patterns and inbreeding levels (Lind-Riehl and Gailing submitted)
Genetic structure of Quercus rubra L. and Quercus ellipsoidalis E. J. Hill populations at gene-based EST-SSR and nuclear SSR markers
No full textSympatric hybridizing oak species provide a model system for studying local adaptation. Disjunct populations of Quercus rubra L. and Quercus ellipsoidalis E. J. Hill at the northern edge of their distribution may harbor important reservoirs of adaptive genetic variation. Genic (expressed sequence tag- simple sequence repeat = EST-SSR) and non-genic nuclear microsatellite (nuclear SSR = nSSR) markers were used to estimate neutral and potentially adaptive genetic variation in these two supposedly interfertile oak species showing different adaptations to drought. Eleven populations of putative Q. rubra and Q. ellipsoidalis located in the Western Upper Peninsula of Michigan were characterized using seven EST-SSRs and eight nSSRs. Bayesian cluster analysis revealed two distinct groups corresponding to each species with evidence of low levels of potential introgression. A comparison of the genetic structure of adult trees and seedlings revealed no evidence for selection against hybrids. Overall, similar levels of genetic variation and differentiation between populations and species were found at both EST-SSRs and nSSRs indicating that most EST-SSRs chosen reflect neutral variation. Two loci, 3A05 (nSSR) and GOT021 (EST-SSR, putative histidine kinase 4-like), were identified as putative outlier loci between species showing largely reduced variation in Q. ellipsoidalis. Future analyses of an increased number of EST-SSRs located in functional genes will allow the identification of genes involved in the reproductive isolation between both species
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Radiocarbon evidence for the early Bronze Age Levant: The site of tell Fadous-Kfarabida (Lebanon) and the end of the early bronze III period
No full textAbsolute dates for the end of the Early Bronze Age ancient Near East are of crucial importance for assessing the nature and extent of mid- to late 3rd millennium BC transitions in the Near East and their alleged link to the 4.2ka BP climatic event. This article presents a radiocarbon sequence for the Early Bronze Age site of Tell Fadous-Kfarabida (Lebanon) and argues that the end of the Early Bronze III period has to be dated considerably higher than previously estimated. There is no reason to assume that the 4.2ka BP event might have contributed to or even triggered the collapse of the first urban cities in the southern and central Levant. © 2014 by the Arizona Board of Regents on behalf of the University of Arizona.Badreshany K, 2005, B ARCHEOLOGIE ARCHIT, V9, P5; Badreshany K, 2009, B AM SCH ORIENT RES, V355, P51; Bar-Matthews M, 2011, HOLOCENE, V21, P163, DOI 10.1177-0959683610384165; Ramsey CB, 2009, RADIOCARBON, V51, P1023; Ramsey CB, 1995, RADIOCARBON, V37, P425; Bronk-Ramsey C., 2002, ARCHAEOMETRY, V44, P1; BUCK CE, 1992, J ARCHAEOL SCI, V19, P497, DOI 10.1016-0305-4403(92)90025-X; Callaway JA, 1978, ARCHAEOLOGY LEVANT, P46; de Miroschedji P, 2012, ALL WISDOM E STUDIES, P265; de Miroschedji P, 2001, B SOC FRANCAISE EGYP, V152, P28; Dever WG, 1970, NEAR E ARCHAEOLOGY, P132; Genz H, 2012, COMPANION ARCHAEOLOG, P607; Genz H, 2009, B ARCHEOLOGIE ARCHIT, VVI, P107; Genz H, 2009, B ARCHEOLOGIE ARCHIT, V13, P71; Genz H, 2008, B ARCHEOLOGIE ARCHIT, V12, P149; Genz H, 2010, B ARCHEOLOGIE ARCHIT, V14, P241; Genz H, 2007, B ARCHEOLOGIE ARCHIT, V11, P7; Genz H, 2010, REPORTS RECENT FIELD, V2, P205; Genz H, 2010, NEAR EAST ARCHAEOL, V73, P102; Genz H, OLD KINGDOM POTTERY, V2; Harrison TP, 2012, COMPANION ARCHAEOLOG, P629; Kenyon K. M., 1966, AMORITES CANAANITES; Knoblauch C, 2010, AGYPTEN LEVANTE, V20, P243; Kohler EC, 2014, ORIENT ARCHAOLOGIE; MAZAR B, 1968, ISRAEL EXPLOR J, V18, P65; Mazzoni S, ASS REGIONA IN PRESS; MIROSCHEDJI P. DE, 2009, SCI ANTICHITA STORIA, V15, P101; Moeller Nadine, 2005, AGYPTEN LEVANTE, VXV, P153; Parr P, 2009, PALESTINE EXPLORATIO, V9; Petrie WMF., 1898, MEMOIR EGYPT EXPLORA, V15; Pfalzner P., 2012, 7 GENERATIONS FALL A, P145; Ramsey CB, 2010, SCIENCE, V328, P1554, DOI 10.1126-science.1189395; Regev J, 2012, RADIOCARBON, V54, P505; Regev J, 2012, RADIOCARBON, V54, P525; Reimer PJ, 2009, RADIOCARBON, V51, P1111; Richards J., 2002, JARCE, V39, P75, DOI 10.2307-40001150; Riehl S, 2012, J ARID ENVIRON, V86, P113, DOI 10.1016-j.jaridenv.2011.09.014; Riehl S, 2007, VARIA ANATOLICA, V19, P523; Rosen A.M., 2007, CIVILIZING CLIMATE S; Sowada KN., 2009, ORBIS BIBLICUS ORIEN, V237; Staubwasser M, 2006, QUATERNARY RES, V66, P372, DOI 10.1016-j.yqres.2006.09.001; Thalmann J., 2006, BIBLIOTHEQUE ARCHEOL, V177; Ur J, 2012, LOOKING N SOCIOECONO; Weiss H., 2000, ENV DISASTER ARCHAEO, P75; WEISS H, 1993, SCIENCE, V261, P995, DOI 10.1126-science.261.5124.995; Weiss H., 2012, 7 GENERATIONS FALL A, P1; Weiss H., 2000, DJEZIRE EUPHRATE SYR, P207; Weiss H, 2001, SCIENCE, V291, P609, DOI 10.1126-science.1058775; Wright GE., 1961, BIBLE ANCIENT NEAR E, P7310
Figure 3 from: Pannell CM, Schnitzler J, Muellner-Riehl AN (2020) Two new species and a new species record of Aglaia (Meliaceae) from Indonesia. PhytoKeys 155: 33-51. https://doi.org/10.3897/phytokeys.155.53833
No full textFigure 3 Aglaia mackianaA leaf with attachment to twig B apex of shoot C detail of upper leaflet surface D detail of lower leaflet surface E immature inflorescence F flower buds G peltate scales H transverse section of immature fruit with three seeds I seed, with large hilum and intact aril (Drawn by Rosemary Wise, edited by Alexandra Muellner-Riehl)
The role of openness in collaborative innovation in industrial networks: historical and contemporary cases
No full textPurpose: This paper aims to explore the role and meaning of openness for the purpose of enhancing the understanding of collaborative innovation from an industrial network perspective. Design/methodology/approach: The theoretical framework is based on the Industrial Network Approach, and the concepts of activity links, resource ties and actor bonds are used as a starting point for capturing the content and dynamics of the interaction. The empirical part consists of five case studies: two historical and three contemporary cases dealing with collaborative innovation projects. The cases are analyzed with regard to openness in business relationships and their connections in the network. Findings: The main contribution is a conceptualization of openness in business relationships and relationship connections. The paper describes various forms and contents of openness – and closeness. It is postulated that the concept of openness can be used as an analytical tool for digging deeper into relationship and network-related issues of relevance to firms’ behavior in the context of collaborative innovation. Openness, as it is defined in this paper, is also put forward as an explanation of why (or why not) collaborative innovation projects become successful. Originality/value: The conceptualization of openness differs from openness as it is commonly described in the open innovation literature. There, openness is the opposite of closeness, that is, a pattern where the innovation activities take place internally within the company. In this paper, openness, instead, has to do with how firms interact with other network actors in the context of collaborative innovation
An other tongue: language and identity in translingual writing
No full textPhDAbandoning one‟s mother tongue for another language is one of the most profound aspects of exile experience, often fraught with feelings of loss and alienation. Yet the linguistic switch can also be viewed as an advantage: the adopted language becomes a refuge, affording the writer creative distance and perspective. This thesis examines the effects of this switch as reflected in the works of two translingual Jewish authors, Stefan Heym (1913-2001) and Jakov Lind (1927-2007). Both were forced into exile after their lives in Germany and Austria were shattered by the rise of Nazism, and both chose English as a medium of artistic expression at certain periods of their lives.
Reading these authors‟ works within their post-war historical context, the thesis argues that translingualism is associated with a psychic split as the self is divided between its languages. This schism manifests itself differently in the writing of each of these authors, according to their distinct perceptions of their identity and place in the world: in Lind‟s work, it is experienced as a schizophrenic existence, and in Heym‟s – as an advantageous doubling of perspective.
The first chapter focuses on autobiographical writing in a foreign language, exploring how self and language are bound together in Lind‟s English-language autobiographies. The second chapter draws on Bakhtin‟s notion of dialogism as it considers the relationship between narration, ideology and propaganda in Heym‟s war novel The Crusaders. The third chapter examines Lind‟s and Heym‟s representations of the writer in their fiction, and how their translingualism defines their perception of their own identity and role as writers. The final chapter shows how the two authors reinterpret the figure of the Wandering Jew to construct different visions of a humanistic Jewish identity that correspond to their own diasporic existence
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