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"Natural selection"

Adriana Suarez-Gonzalez, Christian Lexer, Quentin C B Cronk
Introgression is emerging as an important source of novel genetic variation, alongside standing variation and mutation. It is adaptive when such introgressed alleles are maintained by natural selection. Recently, there has been an explosion in the number of studies on adaptive introgression. In this review, we take a plant perspective centred on four lines of evidence: (i) introgression, (ii) selection, (iii) phenotype and (iv) fitness. While advances in genomics have contributed to our understanding of introgression and porous species boundaries (task 1), and the detection of signatures of selection in introgression (task 2), the investigation of adaptive introgression critically requires links to phenotypic variation and fitness (tasks 3 and 4)...
March 2018: Biology Letters
Md Atique Ahmed, Muh Fauzi, Eun-Taek Han
BACKGROUND: Human infections due to the monkey malaria parasite Plasmodium knowlesi is on the rise in most Southeast Asian countries specifically Malaysia. The C-terminal 19 kDa domain of PvMSP1P is a potential vaccine candidate, however, no study has been conducted in the orthologous gene of P. knowlesi. This study investigates level of polymorphisms, haplotypes and natural selection of full-length pkmsp1p in clinical samples from Malaysia. METHODS: A total of 36 full-length pkmsp1p sequences along with the reference H-strain and 40 C-terminal pkmsp1p sequences from clinical isolates of Malaysia were downloaded from published genomes...
March 14, 2018: Malaria Journal
Marco A Molina-Montenegro, Ian S Acuña-Rodríguez, Tomás S M Flores, Rasme Hereme, Alejandra Lafon, Cristian Atala, Cristian Torres-Díaz
It has been widely suggested that invasion success along broad environmental gradients may be partially due to phenotypic plasticity, but rapid evolution could also be a relevant factor for invasions. Seed and fruit traits can be relevant for plant invasiveness since they are related to dispersal, germination, and fitness. Some seed traits vary along environmental gradients and can be heritable, with the potential to evolve by means of natural selection. Utilizing cross-latitude and reciprocal-transplant experiments, we evaluated the adaptive value of seed thickness as assessed by survival and biomass accumulation in Taraxacum officinale plants...
2018: Frontiers in Plant Science
Joanne M Bennett, Piero Calosi, Susana Clusella-Trullas, Brezo Martínez, Jennifer Sunday, Adam C Algar, Miguel B Araújo, Bradford A Hawkins, Sally Keith, Ingolf Kühn, Carsten Rahbek, Laura Rodríguez, Alexander Singer, Fabricio Villalobos, Miguel Ángel Olalla-Tárraga, Ignacio Morales-Castilla
How climate affects species distributions is a longstanding question receiving renewed interest owing to the need to predict the impacts of global warming on biodiversity. Is climate change forcing species to live near their critical thermal limits? Are these limits likely to change through natural selection? These and other important questions can be addressed with models relating geographical distributions of species with climate data, but inferences made with these models are highly contingent on non-climatic factors such as biotic interactions...
March 13, 2018: Scientific Data
Anushree Sanyal, Jonathan Lenoir, Carmel O'Neill, Frederic Dubois, Guillaume Decocq
PREMISE OF THE STUDY: Nearly all seed plants rely on stored seed reserves before photosynthesis can commence. Natural selection for seed oil traits must have occurred over 319 million years of evolution since the first seed plant ancestor. Accounting for the biogeographic distribution of seed oil traits is fundamental to understanding the mechanisms of adaptive evolution in seed plants. However, the evolution of seed oils is poorly understood. We provide evidence of the adaptive nature of seed oil traits at the intraspecific and interspecific levels in Brassicaceae-an oilseed-rich and economically important plant family...
January 2018: American Journal of Botany
Sami Johan Taipale, Kimmo Kalevi Kahilainen, Gordon William Holtgrieve, Elina Talvikki Peltomaa
The first few months of life is the most vulnerable period for fish and their optimal hatching time with zooplankton prey is favored by natural selection. Traditionally, however, prey abundance (i.e., zooplankton density) has been considered important, whereas prey nutritional composition has been largely neglected in natural settings. High-quality zooplankton, rich in both essential amino acids (EAAs) and fatty acids (FAs), are required as starting prey to initiate development and fast juvenile growth. Prey quality is dependent on environmental conditions, and, for example, eutrophication and browning are two major factors defining primary producer community structures that will directly determine the nutritional quality of the basal food sources (algae, bacteria, terrestrial matter) for zooplankton...
March 2018: Ecology and Evolution
Katja Häkli, Kjartan Østbye, Kimmo K Kahilainen, Per-Arne Amundsen, Kim Præbel
Adaptive radiation is the evolution of ecological and phenotypical diversity. It arises via ecological opportunity that promotes the exploration of underutilized or novel niches mediating specialization and reproductive isolation. The assumed precondition for rapid local adaptation is diversifying natural selection, but random genetic drift could also be a major driver of this process. We used 27 populations of European whitefish ( Coregonus lavaretus ) from nine lakes distributed in three neighboring subarctic watercourses in northern Fennoscandia as a model to test the importance of random drift versus diversifying natural selection for parallel evolution of adaptive phenotypic traits...
March 2018: Ecology and Evolution
Amanda J Zellmer
Gene flow has historically been thought to constrain local adaptation; yet, recent research suggests that populations can diverge despite exchanging genes. Here I use a common garden experiment to assess the combined effects of gene flow and natural selection on morphological variation of 16 wood frog ( Rana sylvatica ) populations, a species known to experience divergent selection pressures in open- and closed-canopy ponds across relatively small geographic scales. Wood frog tadpoles from different ponds showed significant morphological variation associated with canopy type with a trade-off between tail length and body depth consistent with previous research...
March 2018: Ecology and Evolution
Yevgeniy Raynes, C Scott Wylie, Paul D Sniegowski, Daniel M Weinreich
The influence of population size ( N ) on natural selection acting on alleles that affect fitness has been understood for almost a century. As N declines, genetic drift overwhelms selection and alleles with direct fitness effects are rendered neutral. Often, however, alleles experience so-called indirect selection, meaning they affect not the fitness of an individual but the fitness distribution of its offspring. Some of the best-studied examples of indirect selection include alleles that modify aspects of the genetic system such as recombination and mutation rates...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
S-S Dong, Y-J Zhang, Y-X Chen, S Yao, R-H Hao, Y Rong, H-M Niu, J-B Chen, Y Guo, T-L Yang
We aimed to summarize the results of genetic association studies for obesity and provide a comprehensive annotation of all susceptibility single nucleotide polymorphisms (SNPs). A total of 72 studies were summarized, resulting in 90,361 susceptibility SNPs (738 index SNPs and 89,623 linkage disequilibrium SNPs). Over 90% of the susceptibility SNPs are located in non-coding regions, and it is challenging to understand their functional significance. Therefore, we annotated these SNPs by using various functional databases...
March 12, 2018: Obesity Reviews: An Official Journal of the International Association for the Study of Obesity
Jessica M de Souza, Bruno D C Goncalves, Marcus V Gomez, Luciene B Vieira, Fabiola M Ribeiro
Neurodegenerative diseases affect millions of individuals worldwide. So far, no disease-modifying drug is available to treat patients, making the search for effective drugs an urgent need. Neurodegeneration is triggered by the activation of several cellular processes, including oxidative stress, mitochondrial impairment, neuroinflammation, aging, aggregate formation, glutamatergic excitotoxicity, and apoptosis. Therefore, many research groups aim to identify drugs that may inhibit one or more of these events leading to neuronal cell death...
2018: Frontiers in Pharmacology
Maggie R Wagner, Thomas Mitchell-Olds
Phenotypic plasticity is thought to impact evolutionary trajectories by shifting trait values in a direction that is either favored by natural selection ("adaptive plasticity") or disfavored ("nonadaptive" plasticity). However, it is unclear how commonly each of these types of plasticity occurs in natural populations. To answer this question, we measured glucosinolate defensive chemistry and reproductive fitness in over 1,500 individuals of the wild perennial mustard Boechera stricta, planted in four common gardens across central Idaho, USA...
March 9, 2018: Evolution; International Journal of Organic Evolution
Darren C Hunter, Josephine M Pemberton, Jill G Pilkington, Michael B Morrissey
In nature, selection varies across time in most environments, but we lack an understanding of how specific ecological changes drive this variation. Ecological factors can alter phenotypic selection coefficients through changes in trait distributions or individual mean fitness, even when the trait-absolute fitness relationship remains constant. We apply and extend a regression-based approach in a population of Soay sheep (Ovis aries) and suggest metrics of environment-selection relationships that can be compared across studies...
March 8, 2018: Evolution; International Journal of Organic Evolution
Junjie Luo, Yirong Wang, Jian Yuan, Zhilei Zhao, Jian Lu
The repertoire of miRNAs has considerably expanded during metazoan evolution, and duplication is an important mechanism for generating new functional miRNAs. However, relatively little is known about the functional divergence between paralogous miRNAs and the possible co-evolution between duplicated miRNAs and the genomic contexts. By systematically examining small RNA expression profiles across various human tissues and interrogating the publicly available miRNA:mRNA pairing chimeras, we found that changes in expression patterns and targeting preferences are widespread for duplicated miRNAs in vertebrates...
March 6, 2018: RNA
Haiyun Jin, Wan Wang, Xueqin Yang, Hailong Su, Jiawen Fan, Rui Zhu, Shifeng Wang, Huoying Shi, Xiufan Liu
BACKGROUND: Vaccines constitute a unique selective pressure, different from natural selection, drives the evolution of influenza virus. In this study, A/Chicken/Shanghai/F/1998 (H9N2) was continually passaged in specific pathogen-free embryonated chicken eggs with or without selective pressures from antibodies induced by homologous maternal antibodies. Genetic mutations, antigenic drift, replication, and pathogenicity of the passaged virus were evaluated. RESULTS: Antigenic drift of the passaged viruses occurred in the 47th generation (vF47) under selective pressure on antibodies and in the 52nd generation (nF52) without selective pressure from antibodies...
March 6, 2018: BMC Veterinary Research
Timothy D Weaver, Philipp Gunz
Researchers studying extant and extinct taxa are often interested in identifying the evolutionary processes that have lead to the morphological differences among the taxa. Ideally, one could distinguish the influences of neutral evolutionary processes (genetic drift, mutation) from natural selection, and in situations for which selection is implicated, identify the targets of selection. The directional selection gradient is an effective tool for investigating evolutionary process, because it can relate form (size and shape) differences between taxa to the variation and covariation found within taxa...
March 6, 2018: Evolution; International Journal of Organic Evolution
Jérôme Salignon, Magali Richard, Etienne Fulcrand, Hélène Duplus-Bottin, Gaël Yvert
Living systems control cell growth dynamically by processing information from their environment. Although responses to a single environmental change have been intensively studied, little is known about how cells react to fluctuating conditions. Here, we address this question at the genomic scale by measuring the relative proliferation rate (fitness) of 3,568 yeast gene deletion mutants in out-of-equilibrium conditions: periodic oscillations between two environmental conditions. In periodic salt stress, fitness and its genetic variance largely depended on the oscillating period...
March 5, 2018: Molecular Systems Biology
Gamze Sinem Çağlar, Nicolas Garrido
Human papilloma virus (HPV) is one of the most common viral sexually-transmitted diseases worldwide. The prevalence of HPV is higher in infertile males when compared with fertile men and ranges between 10 and 35.7% in men affected by unexplained infertility. HPV can bind to spermatozoa and can potentially be transferred to fertilized oocytes. Viral detection in blastocysts and trophoblastic cells is associated with impaired embryo development and poor pregnancy outcomes. Nevertheless, attempts to eliminate HPV-DNA from sperm samples through routine washing techniques have failed...
March 1, 2018: Journal of the Turkish German Gynecological Association
Mingquan Ding, Z Jeffrey Chen
Polyploidy or whole genome duplication (WGD) is a prominent feature for genome evolution of some animals and all flowering plants, including many important crops such as wheat, cotton, and canola. In autopolyploids, genome duplication often perturbs dosage regulation on biological networks. In allopolyploids, interspecific hybridization could induce genetic and epigenetic changes, the effects of which could be amplified by genome doubling (ploidy changes). Albeit the importance of genetic changes, some epigenetic changes can be stabilized and transmitted as epialleles into the progeny, which are subject to natural selection, adaptation, and domestication...
March 1, 2018: Current Opinion in Plant Biology
Aleksandra V Bezmenova, Georgii A Bazykin, Alexey S Kondrashov
BACKGROUND: Natural selection is possible only because all species produce more offsprings than what is needed to maintain the population. Still, the lifetime number of offspring varies widely across species. One may expect natural selection to be stronger in high-fecundity species. Alternatively, natural selection could be stronger in species where a female invests more into an individual offspring. This issue needed to be addressed empirically. RESULTS: We analyzed the prevalence of loss-of-function alleles in 35 metazoan species and have found that the strength of negative selection does not correlate with lifetime fecundity or other life-history traits...
March 2, 2018: Biology Direct
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