Whose Needs Does Service Serve? Complicating the Citizen Soldier Narrative

The growth of conscript militaries was integral to the creation of civil rights in European nation-states, which established militaries as a key site of claims-making. However, the United States military has diverged from these models, and most cases of inclusion or integration of social groups are not directly connected with claims-making. What has influenced the U.S. military’s responsiveness to pressures, both internal and external, and how has this changed over time? I employ a comparative historical approach to three cases—African-Americans, women, and non-heterosexuals—to unpack the U.S. military as a state institution and a site of claims-making. By incorporating elements unique to American institutions into existing models of militaries, I find that the U.S. military has become increasingly vulnerable to domestic political, international political, internal economic, and internal and external cultural pressures since the World War period. Despite its enormous economic and physical strength, the U.S. military is more responsive now than ever before to internal and external demands

Whole genome surveys of rice, maize and sorghum reveal multiple horizontal transfers of the LTR-retrotransposon Route66 in Poaceae

<p>Abstract</p> <p>Background</p> <p>Horizontal transfers (HTs) refer to the transmission of genetic material between phylogenetically distant species. Although most of the cases of HTs described so far concern genes, there is increasing evidence that some involve transposable elements (TEs) in Eukaryotes. The availability of the full genome sequence of two cereal species, (<it>i.e</it>. rice and <it>Sorghum</it>), as well as the partial genome sequence of maize, provides the opportunity to carry out genome-wide searches for TE-HTs in <it>Poaceae</it>.</p> <p>Results</p> <p>We have identified an LTR-retrotransposon, that we named <it>Route66</it>, with more than 95% sequence identity between rice and <it>Sorghum</it>. Using a combination of <it>in silico </it>and molecular approaches, we are able to present a substantial phylogenetic evidence that <it>Route66 </it>has been transferred horizontally between Panicoideae and several species of the genus <it>Oryza</it>. In addition, we show that it has remained active after these transfers.</p> <p>Conclusion</p> <p>This study constitutes a new case of HTs for an LTR-retrotransposon and we strongly believe that this mechanism could play a major role in the life cycle of transposable elements. We therefore propose to integrate classe I elements into the previous model of transposable element evolution through horizontal transfers.</p

Nucleotide diversity of the ZmPox3 maize peroxidase gene: Relationships between a MITE insertion in exon 2 and variation in forage maize digestibility

BACKGROUND: Polymorphisms were investigated within the ZmPox3 maize peroxidase gene, possibly involved in lignin biosynthesis because of its colocalization with a cluster of QTL related to lignin content and cell wall digestibility. The purpose of this study was to identify, on the basis of 37 maize lines chosen for their varying degrees of cell wall digestibility and representative of temperate regions germplasm, ZmPox3 haplotypes or individual polymorphisms possibly associated with digestibility. RESULTS: Numerous haplotypes with high diversity were identified. Frequency of nucleotide changes was high with on average one SNP every 57 bp. Nucleotide diversity was not equally distributed among site categories: the estimated π was on average eight times higher for silent sites than for non-synonymous sites. Numerous sites were in linkage disequilibrium that decayed with increasing physical distance. A zmPox3 mutant allele, carrying an insertion of a transposable element in the second exon, was found in lines derived from the early flint inbred line, F7. This element possesses many structural features of miniature inverted-repeat transposable elements (MITE). The mutant allele encodes a truncated protein lacking important functional sites. An ANOVA performed with a subset of 31 maize lines indicated that the transposable element was significantly associated with cell wall digestibility. This association was confirmed using an additional set of 25 flint lines related to F7. Moreover, RT-PCR experiments revealed a decreased amount of corresponding mRNA in plants with the MITE insertion. CONCLUSION: These results showed that ZmPox3 could possibly be involved in monolignol polymerisation, and that a deficiency in ZmPox3 peroxidase activity seemingly has a negative effect on cell wall digestibility. Also, genetic diversity analyses of ZmPox3 indicated that this peroxidase could be a relevant target for grass digestibility improvement using specific allele introgressions

Sélection et coévolution de gènes paralogues impliqués dans la synthèse d'amidon au cours de la radiation des angiospermes et chez le maïs, depuis sa domestication

La duplication permet à un gène d'être présent en plusieurs copies dans un génome (gènes paralogues) et peut, à ce titre, conduire à des innovations génétiques. L ADPglucose pyrophosphorylase (AGPase), composée de deux petites sous-unités (SSU) et de deux grandes sous-unités (LSU), est codée par une famille multigénique chez les angiospermes. Elle catalyse une réaction limitante dans la voie de biosynthèse de l amidon et représente ainsi une cible potentielle de la sélection. L objectif de ma thèse a été d étudier l évolution de cette famille à l échelle de la radiation des Angiospermes d une part, et d autre part à une échelle intra-spécifique depuis la domestication du maïs. A l échelle des Angiospermes, les LSUs présentent des sites qui ont évolué sous sélection positive, certains d entre eux appartenant à des domaines fonctionnels importants (liaison au substrat, domaine d interaction entre sous-unités). Au contraire, les SSUs ont évolué sous forte contrainte sélective et montrent des traces de coévolution. Chez le maïs, l AGPase est majoritairement exprimée au niveau de l albumen (gènes SSUend et LSUend), l embryon (SSUemb et LSUemb) et les feuilles (SSUleaf et LSUleaf). La combinaison de plusieurs statistiques ainsi que la prise en compte de la démographie suggèrent des histoires évolutives contrastées, les paralogues ayant évolué sous sélection directionnelle (LSUleaf, LSUend, LSUemb), balancée (SSUemb) ou diversifiante (SSUleaf). Ces résultats illustrent le rôle important de la redondance génétique dans la réponse à la sélection et l évolution des espèces.Gene duplication allows the emergence of multiple copies of a gene in a genome (paralogs) and can ultimately trigger genetic innovation. The AGPase (ADPglucose pyrophosphorylase) encompasses two small subunits (SSU) and two large subunits (LSU). This enzyme is encoded by a multigenic family in Angiosperms. AGPase catalyses a limiting reaction of the starch synthesis pathway and has therefore been likely targeted by selection. During my PhD I studied the evolution of the AGPase multigenic family at an interspecific, during Angiosperm radiation, and at an intraspecific scale since maize domestication. In Angiosperms, a handful of sites in LSUs exhibited signs of positive selection, some of which belong to functional domains such as the interaction domain between subunits and the substrate-binding domain. In contrast, SSUs have evolved under strong selective constraints without convincing evidence of positive selection. Signs of coevolution however were detected within SSUs. In maize, AGPase is expressed mostly in the endosperm (genes SSUend and LSUend), the embryo (SSUemb and LSUemb) and the leaves (SSUleaf and LSUleaf). Using multiple neutrality statistics and accounting for demography, I have shown that the 6 paralogs have evolved under contrasted selective pressures during or after domestication including positive selection (LSUleaf, LSUend, LSUemb), balancing selection (SSUemb) and diversifying selection (SSUleaf). These results illustrate the importance of genetic redundancy in the response to selection and more generally, in species evolution.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Proteomics in Identifying New Regulatory Mechanisms Involved in Seed Development and Ultimately Seed Quality

International audienceMany changes in gene expression occur during maize kernel development. Most changes are associated with the three main developmental stages: lag phase, grain filling, and grain maturation. Proteomics approaches dedicated to non storage proteins coupled with measurements of enzyme activities and metabolite levels provide a way to get an overview of the main metabolic changes and to look at the coordinated variation of the enzymes involved in the main biosynthetic pathways. It also enables to single out specific variation, which may have been overlooked by targeted approaches. Identification of proteins during maize kernel development not only uncovers physiologically consistent protein patterns associated with each stage but also reveals the unexpected importance of some pathways. A major modification occurs at the transition from lag phase (establishment of potential grain size) to grain-filling phase, where starch and proteins are accumulated in the endosperm storage tissue. Although the expression of enzymes involved in the biosynthetic pathway for storage product is dominant in the accumulation phase, the proportion of protein destination (mainly, chaperonins) and protein synthesis machinery is still important. Detailed proteomics analysis of metabolism shows a surprising upsurge of the pyruvate-Pi-dikinase (PPDK) at the late grain-filling period (21 DAP onwards), and that is interpreted as a switch in the starch/protein balance. This hypothesis is based on biochemical arguments involving the negative effect of PPi generated by PPDK activity on the cytosolic ADP-glucose pyrophosphorylase, a key-enzyme in starch synthesis, and the role of phosphoenolpyruvate in aromatic amino acid synthesis. It is substantiated by the molecular genetic data on the O2 gene, which encodes a transcription factor with pleiotropic effects on lysine content, carbohydrate metabolism, and expression of the cyPPDK1 gene. One way to test this hypothesis is to use association genetics on a large panel covering most of the genetic variability in tropical, American, and European maize. After genotyping of 375 lines for O2 and cyPPDK1 genes, a polymorphism in the O2 coding sequence and several polymorphisms along the cyPPDK1 promoter have been identified which are associated in anon-additive way to both the lysine content and the protein versus starch balance. These and other findings are the subject of discussion of this chapter

Molecular evolution accompanying functional divergence of duplicated genes along the plant starch biosynthesis pathway

Background: Starch is the main source of carbon storage in theArchaeplastida. The Starch Biosynthesis Pathway(SBP) emerged from cytosolic glycogen metabolism shortly after plastid endosymbiosis and was redirected to theplastid stroma during the green lineage divergence. The SBP is a complex network of genes, most of which aremembers of large multigene families. While some gene duplications occurred in theArchaeplastidaancestor, mostwere generated during the SBP redirection process, and the remaining few paralogs were generated throughcompartmentalization or tissue specialization during the evolution of the land plants. In the present study, wetested models of duplicated gene evolution in order to understand the evolutionary forces that have led to thedevelopment of SBP in angiosperms. We combined phylogenetic analyses and tests on the rates of evolution alongbranches emerging from major duplication events in six gene families encoding SBP enzymes.Results: We found evidence of positive selection along branches following cytosolic or plastidial specialization intwo starch phosphorylases and identified numerous residues that exhibited changes in volume, polarity or charge.Starch synthases, branching and debranching enzymes functional specializations were also accompanied byaccelerated evolution. However, none of the sites targeted by selection corresponded to known functionaldomains, catalytic or regulatory. Interestingly, among the 13 duplications tested, 7 exhibited evidence of positiveselection in both branches emerging from the duplication, 2 in only one branch, and 4 in none of the branches.Conclusions: The majority of duplications were followed by accelerated evolution targeting specific residues alongboth branches. This pattern was consistent with the optimization of the two sub-functions originally fulfilled by theancestral gene before duplication. Our results thereby provide strong support to the so-called“Escape fromAdaptive Conflict”(EAC) model. Because none of the residues targeted by selection occurred in characterizedfunctional domains, we propose that enzyme specialization has occurred through subtle changes in affinity, activityor interaction with other enzymes in complex formation, while the basic function defined by the catalytic domainhas been maintained

Testing the link between genome size and growth rate in maize

Little is known about the factors driving within species Genome Size (GS) variation. GS may be shaped indirectly by natural selection on development and adaptative traits. Because GS variation is particularly pronounced in maize, we have sampled 83 maize inbred lines from three well described genetic groups adapted to contrasted climate conditions: inbreds of tropical origin, Flint inbreds grown in temperate climates, and Dent inbreds distributed in the Corn Belt. As a proxy for growth rate, we measured the Leaf Elongation Rate maximum during nighttime (LERmax) as well as GS in all inbred lines. In addition we combined available and new nucleotide polymorphism data at 29,090 sites to characterize the genetic structure of our panel. We found significant variation for both LERmax and GS among groups defined by our genetic structuring. Tropicals displayed larger GS than Flints while Dents exhibited intermediate values. LERmax followed the opposite trend with greater growth rate in Flints than in Tropicals. In other words, LERmax and GS exhibited a significantly negative correlation (r = − 0.27). However, this correlation was driven by among-group variation rather than within-group variation—it was no longer significant after controlling for structure and kinship among inbreds. Our results indicate that selection on GS may have accompanied ancient maize diffusion from its center of origin, with large DNA content excluded from temperate areas. Whether GS has been targeted by more intense selection during modern breeding within groups remains an open question

Distribution area of the two floral morphs of <i>Nigella damascena</i> L. (Ranunculaceae): a diachronic study using herbarium specimens collected in France

<p>Perianth dimorphism in <i>Nigella damascena</i> (Ranunculaceae) has been documented for four centuries, and its genetic basis started to be studied almost a century ago. Based on herbarium collections, we reconstructed the evolution of the distribution area of the wild-type (perianth composed of a calyx and nectariferous petals) and mutant (apetalous) floral morphs in mainland France over the last two centuries. We showed that the collection localities of the wild-type morph are mostly concentrated in the southern coastal areas of France, whereas the collection localities of the mutant morph were less numerous but more scattered in France. The collection effort of both morphs peaked in the second half of the nineteenth century and continuously decreased afterwards. Results are interpreted taking into account the biases in the constitution of a herbarium collection. Knowledge about the spatial distribution and the frequency of occurrence of wild-type and mutant populations through time will help botanists and evolutionary biologists investigate the origin and ecological grounds for the maintenance and propagation of the apetalous morph in the wild.</p