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https://www.readbyqxmd.com/read/28626938/role-of-parasite-transmission-in-promoting-inbreeding-i-infection-intensities-drive-individual-parasite-selfing-rates
#1
Jillian T Detwiler, Isabel C Caballero, Charles D Criscione
Among parasitic organisms, inbreeding has been implicated as a potential driver of host-parasite coevolution, drug-resistance evolution, and parasite diversification. Yet, fundamental topics about how parasite life histories impact inbreeding remain to be addressed. In particular, there are no direct selfing-rate estimates for hermaphroditic parasites in nature. Our objectives were to elucidate the mating system of a parasitic flatworm in nature and to understand how aspects of parasite transmission could influence the selfing rates of individual parasites...
June 19, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28617640/microhabitat-and-climatic-niche-change-explain-patterns-of-diversification-among-frog-families
#2
Daniel S Moen, John J Wiens
A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal)...
July 2017: American Naturalist
https://www.readbyqxmd.com/read/28616169/host-sympatry-and-body-size-influence-parasite-straggling-rate-in-a-highly-connected-multihost-multiparasite-system
#3
Jose L Rivera-Parra, Iris I Levin, Kevin P Johnson, Patricia G Parker
Parasite lineages commonly diverge when host lineages diverge. However, when large clades of hosts and parasites are analyzed, some cases suggest host switching as another major diversification mechanism. The first step in host switching is the appearance of a parasite on an atypical host, or "straggling." We analyze the conditions associated with straggling events. We use five species of colonially nesting seabirds from the Galapagos Archipelago and two genera of highly specific ectoparasitic lice to examine host switching...
June 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28615658/serotyping-dengue-virus-with-isothermal-amplification-and-a-portable-sequencer
#4
Junya Yamagishi, Lucky R Runtuwene, Kyoko Hayashida, Arthur E Mongan, Lan Anh Nguyen Thi, Linh Nguyen Thuy, Cam Nguyen Nhat, Kriengsak Limkittikul, Chukiat Sirivichayakul, Nuankanya Sathirapongsasuti, Martin Frith, Wojciech Makalowski, Yuki Eshita, Sumio Sugano, Yutaka Suzuki
The recent development of a nanopore-type portable DNA sequencer has changed the way we think about DNA sequencing. We can perform sequencing directly in the field, where we collect the samples. Here, we report the development of a novel method to detect and genotype tropical disease pathogens, using dengue fever as a model. By combining the sequencer with isothermal amplification that only requires a water bath, we were able to amplify and sequence target viral genomes with ease. Starting from a serum sample, the entire procedure could be finished in a single day...
June 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28598423/diversity-spurs-diversification-in-ecological-communities
#5
Vincent Calcagno, Philippe Jarne, Michel Loreau, Nicolas Mouquet, Patrice David
Diversity is a fundamental, yet threatened, property of ecological systems. The idea that diversity can itself favour diversification, in an autocatalytic process, is very appealing but remains controversial. Here, we study a generalized model of ecological communities and investigate how the level of initial diversity influences the possibility of evolutionary diversification. We show that even simple models of intra- and inter-specific ecological interactions can predict a positive effect of diversity on diversification: adaptive radiations may require a threshold number of species before kicking-off...
June 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28596419/intra-tumor-heterogeneity-novel-approaches-for-resolving-genomic-architecture-and-clonal-evolution
#6
Ravi G Gupta, Robert A Somer
High-throughput genomic technologies have revealed a remarkably complex portrait of intra-tumor heterogeneity in cancer and have shown that tumors evolve through a reiterative process of genetic diversification and clonal selection. This discovery has challenged the classical paradigm of clonal dominance and brought attention to subclonal tumor cell populations that contribute to the cancer phenotype. Dynamic evolutionary models may explain how these populations grow within the ecosystem of tissues, including linear, branching, neutral and punctuated patterns...
June 8, 2017: Molecular Cancer Research: MCR
https://www.readbyqxmd.com/read/28595308/pneumococcal-capsule-synthesis-locus-cps-as-evolutionary-hotspot-with-potential-to-generate-novel-serotypes-by-recombination
#7
Rafal J Mostowy, Nicholas J Croucher, Nicola De Maio, Claire Chewapreecha, Susannah J Salter, Paul Turner, David M Aanensen, Stephen D Bentley, Xavier Didelot, Christophe Fraser
Diversity of the polysaccharide capsule in Streptococcus pneumoniae -- main surface antigen and the target of the currently used pneumococcal vaccines -- constitutes a major obstacle in eliminating pneumococcal disease. Such diversity is genetically encoded by almost 100 variants of the capsule biosynthesis locus, cps. However, the evolutionary dynamics of the capsule remains not fully understood. Here, using genetic data from 4,519 bacterial isolates, we found cps to be an evolutionary hotspot with elevated substitution and recombination rates...
June 8, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28591189/shift-from-slow-to-fast-water-habitats-accelerates-lineage-and-phenotype-evolution-in-a-clade-of-neotropical-suckermouth-catfishes-loricariidae-hypoptopomatinae
#8
Fábio F Roxo, Nathan K Lujan, Victor A Tagliacollo, Brandon T Waltz, Gabriel S C Silva, Claudio Oliveira, James S Albert
Identifying habitat characteristics that accelerate organismal evolution is essential to understanding both the origins of life on Earth and the ecosystem properties that are most critical to maintaining life into the future. Searching for these characteristics on a large scale has only recently become possible via advances in phylogenetic reconstruction, time-calibration, and comparative analyses. In this study, we combine these tools with habitat and phenotype data for 105 species in a clade of Neotropical suckermouth catfishes commonly known as cascudinhos...
2017: PloS One
https://www.readbyqxmd.com/read/28590074/evolutionary-bottlenecks-in-brackish-water-habitats-drive-the-colonization-of-fresh-water-by-stingrays
#9
Kim Nadine Kirchhoff, Torsten Hauffe, Björn Stelbrink, Christian Albrecht, Thomas Wilke
Species richness in freshwater bony fishes depends on two main processes: the transition into and the diversification within freshwater habitats. In contrast to bony fishes, only few cartilaginous fishes, mostly stingrays (Myliobatoidei), were able to colonize fresh water. Respective transition processes have been mainly assessed from a physiological and morphological perspective, indicating that the freshwater lifestyle is strongly limited by the ability to perform osmoregulatory adaptations. However, the transition history and the effect of physiological constraints on the diversification in stingrays remain poorly understood...
June 7, 2017: Journal of Evolutionary Biology
https://www.readbyqxmd.com/read/28584090/paleogenomics-of-echinoids-reveals-an-ancient-origin-for-the-double-negative-specification-of-micromeres-in-sea-urchins
#10
Jeffrey R Thompson, Eric M Erkenbrack, Veronica F Hinman, Brenna S McCauley, Elizabeth Petsios, David J Bottjer
Establishing a timeline for the evolution of novelties is a common, unifying goal at the intersection of evolutionary and developmental biology. Analyses of gene regulatory networks (GRNs) provide the ability to understand the underlying genetic and developmental mechanisms responsible for the origin of morphological structures both in the development of an individual and across entire evolutionary lineages. Accurately dating GRN novelties, thereby establishing a timeline for GRN evolution, is necessary to answer questions about the rate at which GRNs and their subcircuits evolve, and to tie their evolution to paleoenvironmental and paleoecological changes...
June 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28579711/nutritional-status-and-effect-of-maternal-employment-among-children-aged-6-59-months-in-wolayta-sodo-town-southern-ethiopia-a-cross-sectional-study
#11
Hiwot Eshete, Yewelsew Abebe, Eskindir Loha, Teklemichael Gebru, Tesfalem Tesheme
BACKGROUND: Childhood malnutrition remains common in many parts of the world; the magnitude of worldwide stunting, underweight and wasting in children under five years of age were 24.7 %, 15.1 % and 7.8 %, respectively. More than 150 million children under the age of five years in the developing world are malnourished. Ethiopia is one of the countries in sub-Saharan Africa with the highest rates of malnutrition. In Ethiopia, 44.4% and 9.7% of children under-five years old were stunted and wasted, respectively...
March 2017: Ethiopian Journal of Health Sciences
https://www.readbyqxmd.com/read/28574479/r-loops-in-the-regulation-of-antibody-gene-diversification
#12
REVIEW
Rushad Pavri
For nearly three decades, R loops have been closely linked with class switch recombination (CSR), the process that generates antibody isotypes and that occurs via a complex cascade initiated by transcription-coupled mutagenesis in switch recombination sequences. R loops form during transcription of switch recombination sequences in vitro and in vivo, and there is solid evidence that R loops are required for efficient class switching. The classical model of R loops posits that they boost mutation rates by generating stable and long tracts of single-stranded DNA that serve as the substrate for activation induced deaminase (AID), the enzyme that initiates the CSR reaction cascade by co-transcriptionally mutating ssDNA in switch recombination sequences...
June 2, 2017: Genes
https://www.readbyqxmd.com/read/28566093/efficacy-and-short-term-outcomes-of-preoperative-chemoradiotherapy-with-intermittent-oral-tegafur-uracil-plus-leucovorin-in-japanese-rectal-cancer-patients-a-single-center-experience-retrospective-analysis
#13
Ryosuke Nakagawa, Yuji Inoue, Takeshi Ohki, Yuka Kaneko, Fumi Maeda, Masakazu Yamamoto
BACKGROUND: Various types of preoperative chemoradiotherapy (CRT) have been established for rectal cancer; thus, Physicians will need to refine the selection of appropriate preoperative CRT for different patients since there are various treatment regimens. Oral tegafur-uracil (UFT) plus leucovorin (LV) is commonly used to treat rectal cancer in Japan. Oral chemotherapy offers patients many potential advantages. Since 2008, we have been performing preoperative CRT with intermittent oral UFT plus LV in locally advanced rectal cancer patients to prevent postoperative local recurrence...
May 31, 2017: World Journal of Surgical Oncology
https://www.readbyqxmd.com/read/28559330/positive-association-between-population-genetic-differentiation-and-speciation-rates-in-new-world-birds
#14
Michael G Harvey, Glenn F Seeholzer, Brian Tilston Smith, Daniel L Rabosky, Andrés M Cuervo, Robb T Brumfield
An implicit assumption of speciation biology is that population differentiation is an important stage of evolutionary diversification, but its significance as a rate-limiting control on phylogenetic speciation dynamics remains largely untested. If population differentiation within a species is related to its speciation rate over evolutionary time, the causes of differentiation could also be driving dynamics of organismal diversity across time and space. Alternatively, geographic variants might be short-lived entities with rates of formation that are unlinked to speciation rates, in which case the causes of differentiation would have only ephemeral impacts...
May 30, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28545386/evolutionary-radiations-in-the-species-rich-mountain-genus-saxifraga-l
#15
J Ebersbach, J Schnitzler, A Favre, A N Muellner-Riehl
BACKGROUND: A large number of taxa have undergone evolutionary radiations in mountainous areas, rendering alpine systems particularly suitable to study the extrinsic and intrinsic factors that have shaped diversification patterns in plants. The species-rich genus Saxifraga L. is widely distributed throughout the Northern Hemisphere, with high species numbers in the regions adjacent to the Qinghai-Tibet Plateau (QTP) in particular the Hengduan Mountains and the Himalayas. Using a dataset of 297 taxa (representing at least 60% of extant Saxifraga species), we explored the variation of infrageneric diversification rates...
May 25, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28543226/interactions-within-and-between-clades-shaped-the-diversification-of-terrestrial-carnivores
#16
Mathias M Pires, Daniele Silvestro, Tiago B Quental
A longstanding debate in evolutionary biology and paleontology is whether ecological interactions such as competition impose diversity dependence on speciation and extinction rates. Here we analyze the fossil record of terrestrial mammalian carnivores in North America and Eurasia using a Bayesian framework to assess whether their diversity dynamics were affected by diversity dependence within and between families (12 in Eurasia, 10 in North America). We found eight instances of within-clade diversity dependence suppressing speciation rates and detected between-clade effects increasing extinction rates in six instances...
May 22, 2017: Evolution; International Journal of Organic Evolution
https://www.readbyqxmd.com/read/28539522/maintaining-mimicry-diversity-optimal-warning-colour-patterns-differ-among-microhabitats-in-amazonian-clearwing-butterflies
#17
Keith R Willmott, Julia C Robinson Willmott, Marianne Elias, Chris D Jiggins
Mimicry is one of the best-studied examples of adaptation, and recent studies have provided new insights into the role of mimicry in speciation and diversification. Classical Müllerian mimicry theory predicts convergence in warning signal among protected species, yet tropical butterflies are exuberantly diverse in warning colour patterns, even within communities. We tested the hypothesis that microhabitat partitioning in aposematic butterflies and insectivorous birds can lead to selection for different colour patterns in different microhabitats and thus help maintain mimicry diversity...
May 31, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28532532/global-phylogenetic-relationships-population-structure-and-gene-flow-estimation-of-trialeurodes-vaporariorum-greenhouse-whitefly
#18
J M Wainaina, P De Barro, L Kubatko, M A Kehoe, J Harvey, D Karanja, L M Boykin
Trialeurodes vaporariorum (Westwood, 1856) (Greenhouse whitefly) is an agricultural pest of global importance. It is associated with damage to plants during feeding and subsequent virus transmission. Yet, global phylogenetic relationships, population structure, and estimation of the rates of gene flow within this whitefly species remain largely unexplored. In this study, we obtained and filtered 227 GenBank records of mitochondrial cytochrome c oxidase I (mtCOI) sequences of T. vaporariorum, across various global locations to obtain a final set of 217 GenBank records...
May 23, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/28529152/coevolution-of-patch-type-dependent-emigration-and-patch-type-dependent-immigration
#19
Helene C Weigang
The three phases of dispersal - emigration, transfer and immigration - are affecting each other and the former and latter decisions may depend on patch types. Despite the inevitable fact of the complexity of the dispersal process, patch-type dependencies of dispersal decisions modelled as emigration and immigration are usually missing in theoretical dispersal models. Here, I investigate the coevolution of patch-type dependent emigration and patch-type dependent immigration in an extended Hamilton-May model...
May 18, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28528744/locked-in-the-icehouse-evolution-of-an-endemic-epimeria-amphipoda-crustacea-species-flock-on-the-antarctic-shelf
#20
Marie L Verheye, Thierry Backeljau, Cédric d'Udekem d'Acoz
The Antarctic shelf's marine biodiversity has been greatly influenced by the climatic and glacial history of the region. Extreme temperature changes led to the extinction of some lineages, while others adapted and flourished. The amphipod genus Epimeria is an example of the latter, being particularly diverse in the Antarctic region. By reconstructing a time-calibrated phylogeny based on mitochondrial (COI) and nuclear (28S and H3) markers and including Epimeria species from all oceans, this study provides a temporal and geographical framework for the evolution of Antarctic Epimeria...
May 18, 2017: Molecular Phylogenetics and Evolution
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