7,752 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)
Fine-scale spatial genetic structure of two red oak species, Quercus rubra and Quercus ellipsoidalis
No full textPeripheral populations located at their range edge, may be at risk due to geographical isolation, environmental changes, human disturbances or catastrophic events such as wildfires. Fine-scale spatial genetic structure (SGS) investigations provide a way to examine the spatial arrangement of genetic variation within populations. SGS can result from restricted seed and pollen dispersal and might be affected by geographic isolation and environmental changes and disturbances even in outcrossing wind-pollinated species like oaks. Studying the SGS of peripheral populations provides information that can be used to develop improved conservation and management plans at the species’ range edge. We assessed the level of genetic variation and SGS in twelve range edge populations in northern Wisconsin and the Upper Peninsula of Michigan (USA): eight Quercus rubra and four Quercus ellipsoidalis populations that were subject to different management regimes and natural disturbances. In contrast to Q. rubra populations, the drought tolerant Q. ellipsoidalis populations are isolated from the species’ main distribution range. These populations are not actively managed but are especially prone to recurring fire events. The four managed and four old growth (“unmanaged”) Q. rubra populations displayed similar levels of genetic variation. Likewise the Sp statistic showed similar SGS levels in managed and unmanaged Q. rubra populations (Sp = 0.005) comparable to other Quercus species (European Q. robur: Sp = 0.003). Q. ellipsoidalis populations showed similar or more pronounced SGS than neighboring Q. rubra populations extending up to 83 m in one population. A significant excess of homozygotes across markers in two of the Q. ellipsoidalis populations suggests potential inbreeding. In summary, diverse management activities combined with various natural disturbances are likely both influencing SGS patterns. Outcrossing forest trees like oaks hold large amounts of genetic diversity allowing adaptation to environmental changes over their long life spans. Reductions of these genetic stores, through inbreeding for example, can inhibit a species’ ability to adapt to changing environmental conditions
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
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)
Jennifer-Angoh/Pine-Marten-Rodent: v.1.0.0
No full text<p>Code for article "How do microtine rodent abundance, snow and landscape parameters influence pine marten Martes martes population dynamics?". Authors: Siow Yan Jennifer Angoh Affiliation: Inland Norway University of Applied Sciences, NO-2480, Koppang, Norway. Corresponding author: Siow Yan Jennifer Angoh, [email protected], ORCID: <a href="https://orcid.org/0000-0002-3791-0150">https://orcid.org/0000-0002-3791-0150</a></p>
<p><strong>Full Changelog</strong>: <a href="https://github.com/Jennifer-Angoh/Pine-Marten-Rodent/commits/Pine-Marten-Rodent">https://github.com/Jennifer-Angoh/Pine-Marten-Rodent/commits/Pine-Marten-Rodent</a></p>
Jennifer-Angoh/Pine-Marten-Rodent: v.1.0.1
No full text<p>Code for article "How do microtine rodent abundance, snow and landscape parameters influence pine marten Martes martes population dynamics?". Authors: Siow Yan Jennifer Angoh Affiliation: Inland Norway University of Applied Sciences, NO-2480, Koppang, Norway. Corresponding author: Siow Yan Jennifer Angoh, [email protected], ORCID: <a href="https://orcid.org/0000-0002-3791-0150">https://orcid.org/0000-0002-3791-0150</a></p>
<p><strong>Full Changelog</strong>: <a href="https://github.com/Jennifer-Angoh/Pine-Marten-Rodent/commits/Pine-Marten-Rodent">https://github.com/Jennifer-Angoh/Pine-Marten-Rodent/commits/Pine-Marten-Rodent</a></p>
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
Dr. Jennifer Bowie – Faculty Author Interview
No full textDr. Jennifer Bowie, Assistant Professor of Political Science, is the co-author of a new book, The View from the Bench and Chambers: Examining Judicial Process and Decision Making on the U.S. Courts of Appeals, published recently by the University of Virginia Press. This book presents a series of quantitative analyses of judicial decisions in the Courts of Appeals with the perspectives gained from in-depth interviews with the judges and their law clerks
Ep. #136 - Jennifer Gabrys
No full textThis recording and transcript form part of a collection of podcasts conducted by the Cultures of Energy at Rice University. Cultures of Energy brings writers, artists and scholars together to talk, think and feel their way into the Anthropocene. We cover serious issues like climate change, species extinction and energy transition. But we also try to confront seemingly huge and insurmountable problems with insight, creativity and laughter.Your cohosts discuss what sensory technologies they might wish for their own home and the kind of multispecies encounters Cymene might have had in a Tegucigalpa red light district hotel (trigger warning: there be cockroach stories ahead!) Then (20:29) we chat with the multitalented Jennifer Gabrys from Goldsmiths (https://www.jennifergabrys.net), author most recently of Program Earth (U Minnesota Press, 2016), and her fascinating work on the spread of environmental sensing technologies and the impacts they are having on our worlds. Jennifer explains to us why she became taken with Whitehead’s concept of the “superject” as a different, more distributed and relational way of thinking about sensation and experience. That gets us to talking about nonhuman modes of sensing, what humans want from all these sensors, the problem of environmentality in smart city designs, computational urbanism, and why the figure of the idiot interests her in terms of thinking about models of digital participation. Jennifer explains how we can be for a world (and for other worlds) rather than simply of the world and why the etho-ecological is thus such an interesting domain for her. In closing, we return to Jennifer’s pathbreaking work on digital waste and the need for electronic environmentalism and talk about the e-waste/energy nexus and the paradox of spending ever more energy to monitoring ourselves using more energy. Listen on
Author and poet Lily Brett at the National Library of Australia, Canberra, 18 October 2012 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author and poet Lily Brett at the National Library of Australia, Canberra, 18 October 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
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