424 research outputs found
The discipline and disciplining of Margaret Sanger: US birth control rhetoric in the early twentieth century
Margaret Sanger\u27s rhetoric in the US birth control movement demonstrates the social forces that act upon rhetors and women\u27s bodies, conforming both to established gender norms even as they attempt to violate those standards. This project studies Sanger\u27s birth control rhetoric to understand how her arguments for women\u27s right to contraception conformed women\u27s bodies to traditional feminine notions despite her early efforts to contradict such dictates of domesticity. Research on nineteenth-century feminist rhetors demonstrates a pattern of women challenging feminine ideals by speaking publicly but replicating the familiar themes that women must care for others. To explain such a pattern, this study combines the theories of interpretation and genealogy to analyze texts\u27 meanings with a respect for the ways that social forces conform speakers to already established norms and themes. This project follows genealogical demands for a complex history by discussing the discourses that challenge and support early twentieth century birth control rhetoric . Early themes in Sanger\u27s rhetoric focus on issues of class and women\u27s personal liberation. Analysis shows that Sanger begins by addressing the class oppression working class experience before engaging in class maternalism in which she condescends to lower class women setting upper class women as examples of bodily discipline. Sanger\u27s early themes of birth control as women\u27s liberation give way to an emphasis upon women using birth control to better serve their families, thereby fulfilling their maternal duties. Later themes in Sanger\u27s rhetoric emphasize birth control\u27s utility to the state for managing the rate and quality of women\u27s reproduction. The movement from earlier to later themes in Sanger\u27s rhetoric shifts from speaking about women as subject with control of their bodies to objects whose bodies must be controlled. Employing capitalistic themes, Sanger argues that women\u27s rate of reproduction must be controlled to safeguard national security. Using notions of social evolution, Sanger engages in eugenic discourse to demand the control of women\u27s bodies who produce unfit offspring. The sweep of Sanger\u27s rhetoric proves the utility of genealogical interpretation to understand the dynamics of power and discourse that conform feminist speakers to accepted gender definitions
Unexpected ancestry of Populus seedlings from a hybrid zone implies a large role for postzygotic selection in the maintenance of species
In the context of potential interspecific gene flow, the integrity of species will be maintained by reproductive barriers that reduce genetic exchange, including traits associated with prezygotic isolation or poor performance of hybrids. Hybrid zones can be used to study the importance of different reproductive barriers, particularly when both parental species and hybrids occur in close spatial proximity. We investigated the importance of barriers to gene flow that act early versus late in the life cycle of European Populus by quantifying the prevalence of homospecific and hybrid matings within a mosaic hybrid zone. We obtained genotypic data for 11,976 loci from progeny and their maternal parents and constructed a Bayesian model to estimate individual admixture proportions and hybrid classes for sampled trees, and for the unsampled pollen parent. Matings that included one or two hybrid parents were common, resulting in admixture proportions of progeny that spanned the whole range of potential ancestries between the two parental species. This result contrasts strongly with the distribution of admixture proportions in adult trees, where intermediate hybrids and each of the parental species are separated into three discrete ancestry clusters. The existence of the full range of hybrids in seedlings is consistent with weak reproductive isolation early in the life cycle of Populus. Instead, a considerable amount of selection must take place between the seedling stage and maturity to remove many hybrid seedlings. Our results highlight that high hybridization rates and appreciable hybrid fitness do not necessarily conflict with the maintenance of species integrity
THE VARIABLE GENOMIC ARCHITECTURE OF ISOLATION BETWEEN HYBRIDIZING SPECIES OF HOUSE MICE
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/1/EVO_846_sm_FigS3A.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/2/EVO_846_sm_legend.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/3/EVO_846_sm_FigS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/4/j.1558-5646.2009.00846.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/5/EVO_846_sm_FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/6/EVO_846_sm_FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75350/7/EVO_846_sm_FigS3B.pd
Transcriptome sequencing in an ecologically important tree species: assembly, annotation, and marker discovery
<p>Abstract</p> <p>Background</p> <p>Massively parallel sequencing of cDNA is now an efficient route for generating enormous sequence collections that represent expressed genes. This approach provides a valuable starting point for characterizing functional genetic variation in non-model organisms, especially where whole genome sequencing efforts are currently cost and time prohibitive. The large and complex genomes of pines (<it>Pinus </it>spp.) have hindered the development of genomic resources, despite the ecological and economical importance of the group. While most genomic studies have focused on a single species (<it>P. taeda</it>), genomic level resources for other pines are insufficiently developed to facilitate ecological genomic research. Lodgepole pine (<it>P. contorta</it>) is an ecologically important foundation species of montane forest ecosystems and exhibits substantial adaptive variation across its range in western North America. Here we describe a sequencing study of expressed genes from <it>P. contorta</it>, including their assembly and annotation, and their potential for molecular marker development to support population and association genetic studies.</p> <p>Results</p> <p>We obtained 586,732 sequencing reads from a 454 GS XLR70 Titanium pyrosequencer (mean length: 306 base pairs). A combination of reference-based and <it>de novo </it>assemblies yielded 63,657 contigs, with 239,793 reads remaining as singletons. Based on sequence similarity with known proteins, these sequences represent approximately 17,000 unique genes, many of which are well covered by contig sequences. This sequence collection also included a surprisingly large number of retrotransposon sequences, suggesting that they are highly transcriptionally active in the tissues we sampled. We located and characterized thousands of simple sequence repeats and single nucleotide polymorphisms as potential molecular markers in our assembled and annotated sequences. High quality PCR primers were designed for a substantial number of the SSR loci, and a large number of these were amplified successfully in initial screening.</p> <p>Conclusions</p> <p>This sequence collection represents a major genomic resource for <it>P. contorta</it>, and the large number of genetic markers characterized should contribute to future research in this and other pines. Our results illustrate the utility of next generation sequencing as a basis for marker development and population genomics in non-model species.</p
Recent Hybrids Recapitulate Ancient Hybrid Outcomes
Genomic outcomes of hybridization depend on selection and recombination in hybrids. Whether these processes have similar effects on hybrid genome composition in contemporary hybrid zones versus ancient hybrid lineages is unknown. Here we show that patterns of introgression in a contemporary hybrid zone in Lycaeides butterflies predict patterns of ancestry in geographically adjacent, older hybrid populations. We find a particularly striking lack of ancestry from one of the hybridizing taxa, Lycaeides melissa, on the Z chromosome in both the old and contemporary hybrids. The same pattern of reduced L. melissa ancestry on the Z chromosome is seen in two other ancient hybrid lineages. More generally, we find that patterns of ancestry in old or ancient hybrids are remarkably predictable from contemporary hybrids, which suggests selection and recombination affect hybrid genomes in a similar way across disparate time scales and during distinct stages of speciation and species breakdown
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Carbon Monoxide Abrogates Ischemic Insult to Neuronal Cells via the Soluble Guanylate Cyclase-cGMP Pathway
Purpose Carbon monoxide (CO) is an accepted cytoprotective molecule. The extent and mechanisms of protection in neuronal systems have not been well studied. We hypothesized that delivery of CO via a novel releasing molecule (CORM) would impart neuroprotection in vivo against ischemia-reperfusion injury (IRI)-induced apoptosis of retinal ganglion cells (RGC) and in vitro of neuronal SH-SY5Y-cells via activation of soluble guanylate-cyclase (sGC). Methods: To mimic ischemic respiratory arrest, SH-SY5Y-cells were incubated with rotenone (100 nmol/L, 4 h) ± CORM ALF186 (10–100 µmol/L) or inactivated ALF186 lacking the potential of releasing CO. Apoptosis and reactive oxygen species (ROS) production were analyzed using flow-cytometry (Annexin V, mitochondrial membrane potential, CM-H2DCFDA) and Western blot (Caspase-3). The impact of ALF186± respiratory arrest on cell signaling was assessed by measuring expression of nitric oxide synthase (NOS) and soluble guanylate-cyclase (sGC) and by analyzing cellular cGMP levels. The effect of ALF186 (10 mg/kg iv) on retinal IRI in Sprague-Dawley rats was assessed by measuring densities of fluorogold-labeled RGC after IRI and by analysis of apoptosis-related genes in retinal tissue. Results: ALF186 but not inactivated ALF186 inhibited rotenone-induced apoptosis (Annexin V positive cells: 25±2% rotenone vs. 14±1% ALF186+rotenone, p<0.001; relative mitochondrial membrane potential: 17±4% rotenone vs. 55±3% ALF186+rotenone, p<0.05). ALF186 increased cellular cGMP levels (33±5 nmol/L vs. 23±3 nmol/L; p<0.05) and sGC expression. sGC-inhibition attenuated ALF186-mediated protection (relative mitochondrial membrane potential: 55±3% ALF186+rotenone vs. 20±1% ODQ+ALF186+rotenone, p<0.05). ALF186 protected RGC in vivo (IRI 1255±327 RGC/mm2 vs. ALF186+IRI 2036±83; p<0.05) while sGC inhibition abolished the protective effects of ALF186 (ALF186+IRI 2036±83 RGC/mm2 vs. NS-2028+ALF186+IRI 1263±170, p<0.05). Conclusions: The CORM ALF186 inhibits IRI-induced neuronal cell death via activation of sGC and may be a useful treatment option for acute ischemic insults to the retina and the brain
The genetic architecture of divergence between threespine stickleback species.
The genetic and molecular basis of morphological evolution is poorly understood, particularly in vertebrates. Genetic studies of the differences between naturally occurring vertebrate species have been limited by the expense and difficulty of raising large numbers of animals and the absence of molecular linkage maps for all but a handful of laboratory and domesticated animals. We have developed a genome-wide linkage map for the three-spined stickleback (Gasterosteus aculeatus), an extensively studied teleost fish that has undergone rapid divergence and speciation since the melting of glaciers 15,000 years ago. Here we use this map to analyse the genetic basis of recently evolved changes in skeletal armour and feeding morphologies seen in the benthic and limnetic stickleback species from Priest Lake, British Columbia. Substantial alterations in spine length, armour plate number, and gill raker number are controlled by genetic factors that map to independent chromosome regions. Further study of these regions will help to define the number and type of genetic changes that underlie morphological diversification during vertebrate evolution
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Modelling road hazards and the effect on AV safety of hazardous failures
Autonomous vehicles (AV) are about to appear on our roads within the next few years. However, to achieve the final breakthrough, not only functional progress is required, but also fundamental safety questions must be solved. Among those, a question demanding special attention is the need to assess the overall safety of an AV and quantify that it is safe enough to take part in normal traffic despite its inherent imperfections. Therefore, this paper describes a probabilistic model, which allows to study how imperfections of an AV perception system and of mechanisms responsible for AV safety (e.g., Safety Monitors), can impact AV safety in the presence of road hazards. We also demonstrate how the model can be used to validate if the AV is safe enough, to understand the criticality of (perception) errors, and to identify areas/parameters that have more influence on safety than others
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Admixture mapping in interspecific Populus hybrids identifies classes of genomic architectures for phytochemical, morphological and growth traits
The genomic architecture of functionally important traits is key to understanding the maintenance of reproductive barriers and trait differences when divergent populations or species hybridize. We conducted a genome-wide association study (GWAS) to study trait architecture in natural hybrids of two ecologically divergent Populus species. We genotyped 472 seedlings from a natural hybrid zone of Populus alba and Populus tremula for genome-wide markers from reduced representation sequencing, phenotyped the plants in common gardens for 46 phytochemical (phenylpropanoid), morphological and growth traits, and used a Bayesian polygenic model for mapping. We detected three classes of genomic architectures: traits with finite, detectable associations of genetic loci with phenotypic variation in addition to highly polygenic heritability; traits with indications for polygenic heritability only; and traits with no detectable heritability. For the first class, we identified genome regions with plausible candidate genes for phenylpropanoid biosynthesis or its regulation, including MYB transcription factors and glycosyl transferases. GWAS in natural, recombinant hybrids represent a promising step towards resolving the genomic architecture of phenotypic traits in long-lived species. This facilitates the fine-mapping and subsequent functional characterization of genes and networks causing differences in hybrid performance and fitness
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