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evolutionary genetics

Katrin Ehlers, Amey S Bhide, Dawit G Tekleyohans, Benjamin Wittkop, Rod J Snowdon, Annette Becker
Seed formation is a pivotal process in plant reproduction and dispersal. It begins with megagametophyte development in the ovule, followed by fertilization and subsequently coordinated development of embryo, endosperm, and maternal seed coat. Two closely related MADS-box genes, SHATTERPROOF 1 and 2 (SHP1 and SHP2) are involved in specifying ovule integument identity in Arabidopsis thaliana. The MADS box gene ARABIDOPSIS BSISTER (ABS or TT16) is required, together with SEEDSTICK (STK) for the formation of endothelium, part of the seed coat and innermost tissue layer formed by the maternal plant...
2016: PloS One
Lize Cuypers, Guangdi Li, Christoph Neumann-Haefelin, Supinya Piampongsant, Pieter Libin, Kristel Van Laethem, Anne-Mieke Vandamme, Kristof Theys
Despite significant progress in hepatitis C (HCV) treatment, global viral eradication remains a challenge. An in-depth map of its genome diversity within the context of structural and immunological constraints could contribute to the design of pan-genotypic antivirals and preventive vaccines. For such analyses, extensive information is only available for the highly prevalent HCV genotypes (GT) 1a and 1b. Using 647 GT1a and 408 GT1b full-genome sequences obtained from the Los Alamos database, we found that respectively 3 per cent and 82 per cent of all codon positions are under positive and negative selective pressure, suggesting variation mainly accumulates due to random genetic drift...
July 2016: Virus Evolution
Filip Bielejec, Guy Baele, Allen G Rodrigo, Marc A Suchard, Philippe Lemey
Various factors determine the rate at which mutations are generated and fixed in viral genomes. Viral evolutionary rates may vary over the course of a single persistent infection and can reflect changes in replication rates and selective dynamics. Dedicated statistical inference approaches are required to understand how the complex interplay of these processes shapes the genetic diversity and divergence in viral populations. Although evolutionary models accommodating a high degree of complexity can now be formalized, adequately informing these models by potentially sparse data, and assessing the association of the resulting estimates with external predictors, remains a major challenge...
July 2016: Virus Evolution
Truc T Pham, Shengli Meng, Yan Sun, Wenli Lv, Justin Bahl
A comprehensive monitoring strategy is vital for tracking the spread of mosquito-borne Japanese encephalitis virus (JEV), the leading cause of viral encephalitis in Asia. Virus detection consists of passive surveillance of primarily humans and swine, and/or active surveillance in mosquitoes, which may be a valuable proxy in providing insights into ecological processes underlying the spread and persistence of JEV. However, it has not been well characterized whether passive surveillance alone can capture the circulating genetic diversity to make reasonable inferences...
January 2016: Virus Evolution
Andrew Rambaut, Tommy T Lam, Luiz Max Carvalho, Oliver G Pybus
Gene sequences sampled at different points in time can be used to infer molecular phylogenies on a natural timescale of months or years, provided that the sequences in question undergo measurable amounts of evolutionary change between sampling times. Data sets with this property are termed heterochronous and have become increasingly common in several fields of biology, most notably the molecular epidemiology of rapidly evolving viruses. Here we introduce the cross-platform software tool, TempEst (formerly known as Path-O-Gen), for the visualization and analysis of temporally sampled sequence data...
January 2016: Virus Evolution
Héctor Cervera, Santiago F Elena
A long-standing observation in evolutionary virology is that RNA virus populations are highly polymorphic, composed by a mixture of genotypes whose abundances in the population depend on complex interaction between fitness differences, mutational coupling and genetic drift. It was shown long ago, though in cell cultures, that most of these genotypes had lower fitness than the population they belong, an observation that explained why single-virion passages turned on Muller's ratchet while very large population passages resulted in fitness increases in novel environments...
January 2016: Virus Evolution
Christina Kratsch, Thorsten R Klingen, Linda Mümken, Lars Steinbrück, Alice C McHardy
Human influenza viruses are rapidly evolving RNA viruses that cause short-term respiratory infections with substantial morbidity and mortality in annual epidemics. Uncovering the general principles of viral coevolution with human hosts is important for pathogen surveillance and vaccine design. Protein regions are an appropriate model for the interactions between two macromolecules, but the currently used epitope definition for the major antigen of influenza viruses, namely hemagglutinin, is very broad. Here, we combined genetic, evolutionary, antigenic, and structural information to determine the most relevant regions of the hemagglutinin of human influenza A/H3N2 viruses for interaction with human immunoglobulins...
January 2016: Virus Evolution
Gytis Dudas, Andrew Rambaut
Recombination is a process that unlinks neighboring loci allowing for independent evolutionary trajectories within genomes of many organisms. If not properly accounted for, recombination can compromise many evolutionary analyses. In addition, when dealing with organisms that are not obligately sexually reproducing, recombination gives insight into the rate at which distinct genetic lineages come into contact. Since June 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) has caused 1,106 laboratory-confirmed infections, with 421 MERS-CoV-associated deaths as of 16 April 2015...
January 2016: Virus Evolution
Satoshi Komoto, Yaowapa Pongsuwanna, Ratana Tacharoenmuang, Ratigorn Guntapong, Tomihiko Ide, Kyoko Higo-Moriguchi, Takao Tsuji, Tetsushi Yoshikawa, Koki Taniguchi
Bovine group A rotavirus (RVA) is an important cause of acute diarrhea in calves worldwide. In order to obtain precise information on the origin and evolutionary dynamics of bovine RVA strains, we determined and analyzed the complete nucleotide sequences of the whole genomes of six archival bovine RVA strains; four Thai strains (RVA/Cow-tc/THA/A5-10/1988/G8P[1], RVA/Cow-tc/THA/A5-13/1988/G8P[1], RVA/Cow-tc/THA/61A/1989/G10P[5], and RVA/Cow-tc/THA/A44/1989/G10P[11]), one American strain (RVA/Cow-tc/USA/B223/1983/G10P[11]), and one Japanese strain (RVA/Cow-tc/JPN/KK3/1983/G10P[11])...
November 15, 2016: Veterinary Microbiology
M C Fontaine
The harbour porpoise, Phocoena phocoena, is one of the best studied cetacean species owing to its common distribution along the coastal waters of the Northern Hemisphere. In European waters, strandings are common and bycatch mortalities in commercial fisheries reach alarming numbers. Lethal interactions resulting from human activities together with ongoing environmental changes raise serious concerns about population viability throughout the species' range. These concerns foster the need to fill critical gaps in knowledge of harbour porpoise biology, including population structure, feeding ecology, habitat preference and evolutionary history, that are critical information for planning effective management and conservation efforts...
2016: Advances in Marine Biology
Daniel Nichol, Mark Robertson-Tessi, Peter Jeavons, Alexander R A Anderson
Non-genetic variation in phenotypes, or bet-hedging, has been observed as a driver of drug resistance in both bacterial infections and cancers. Here, we study how bet-hedging emerges in the genotype-phenotype mapping through a simple interaction model: a molecular switch. We use simple Chemical Reaction Networks to implement stochastic switches that map gene products to phenotypes and investigate the impact of structurally distinct mappings on the evolution of phenotypic heterogeneity. Bet-hedging naturally emerges within this model and is robust to evolutionary loss through mutations to both the expression of individual genes and to the network itself...
October 21, 2016: Genetics
V Rougeron, T De Meeûs, A-L Bañuls
One key process of the life cycle of pathogens is their mode of reproduction. Indeed, this fundamental biological process conditions the multiplication and the transmission of genes and thus the propagation of diseases in the environment. Reproductive strategies of protozoan parasites have been a subject of debate for many years, principally due to the difficulty in making direct observations of sexual reproduction (i.e. genetic recombination). Traditionally, these parasites were considered as characterized by a preeminent clonal structure...
October 18, 2016: Infection, Genetics and Evolution
Kattina Zavala, Michael W Vandewege, Federico G Hoffmann, Juan C Opazo
The study of the evolutionary history of genes related to human disease lies at the interface of evolution and medicine. These studies provide the evolutionary context on which medical researchers should work, and are also useful in providing information to suggest further genetic experiments, especially in model species where genetic manipulations can be made. Here we studied the evolution of the β-adrenoreceptor gene family in vertebrates with the aim of adding an evolutionary framework to the already abundant physiological information...
October 18, 2016: General and Comparative Endocrinology
Diyendo Massilani, Silvia Guimaraes, Jean-Philip Brugal, E Andrew Bennett, Malgorzata Tokarska, Rose-Marie Arbogast, Gennady Baryshnikov, Gennady Boeskorov, Jean-Christophe Castel, Sergey Davydov, Stéphane Madelaine, Olivier Putelat, Natalia N Spasskaya, Hans-Peter Uerpmann, Thierry Grange, Eva-Maria Geigl
BACKGROUND: Climatic and environmental fluctuations as well as anthropogenic pressure have led to the extinction of much of Europe's megafauna. The European bison or wisent (Bison bonasus), one of the last wild European large mammals, narrowly escaped extinction at the onset of the 20th century owing to hunting and habitat fragmentation. Little is known, however, about its origin, evolutionary history and population dynamics during the Pleistocene. RESULTS: Through ancient DNA analysis we show that the emblematic European bison has experienced several waves of population expansion, contraction, and extinction during the last 50,000 years in Europe, culminating in a major reduction of genetic diversity during the Holocene...
October 21, 2016: BMC Biology
Hélène Quach, Maxime Rotival, Julien Pothlichet, Yong-Hwee Eddie Loh, Michael Dannemann, Nora Zidane, Guillaume Laval, Etienne Patin, Christine Harmant, Marie Lopez, Matthieu Deschamps, Nadia Naffakh, Darragh Duffy, Anja Coen, Geert Leroux-Roels, Frederic Clément, Anne Boland, Jean-François Deleuze, Janet Kelso, Matthew L Albert, Lluis Quintana-Murci
Humans differ in the outcome that follows exposure to life-threatening pathogens, yet the extent of population differences in immune responses and their genetic and evolutionary determinants remain undefined. Here, we characterized, using RNA sequencing, the transcriptional response of primary monocytes from Africans and Europeans to bacterial and viral stimuli-ligands activating Toll-like receptor pathways (TLR1/2, TLR4, and TLR7/8) and influenza virus-and mapped expression quantitative trait loci (eQTLs)...
October 20, 2016: Cell
Michael R Gillings, Ian T Paulsen, Sasha G Tetu
Antibiotic resistance arises as a consequence of complex interactions among genes, mobile elements, and their bacterial hosts, coupled with the intense selection pressures imposed by humans in an attempt to control bacterial growth. Understanding the evolution of resistance requires an understanding of interacting cellular and genetic components. Here, we review how DNA analysis has helped reconstruct the origins of the mosaic, multiresistant mobile elements that have spread through pathogens in the last 60 years...
October 21, 2016: Annals of the New York Academy of Sciences
Kerry A Geiler-Samerotte, Yuan O Zhu, Benjamin E Goulet, David W Hall, Mark L Siegal
The protein-folding chaperone Hsp90 has been proposed to buffer the phenotypic effects of mutations. The potential for Hsp90 and other putative buffers to increase robustness to mutation has had major impact on disease models, quantitative genetics, and evolutionary theory. But Hsp90 sometimes contradicts expectations for a buffer by potentiating rapid phenotypic changes that would otherwise not occur. Here, we quantify Hsp90's ability to buffer or potentiate (i.e., diminish or enhance) the effects of genetic variation on single-cell morphological features in budding yeast...
October 2016: PLoS Biology
Xingguang Li, Junjie Zai, Haizhou Liu, Yi Feng, Fan Li, Jing Wei, Sen Zou, Zhiming Yuan, Yiming Shao
Following its immergence in December 2013, the recent Zaire Ebola virus (EBOV) outbreak in West Africa has spread and persisted for more than two years, making it the largest EBOV epidemic in both scale and geographical region to date. In this study, a total of 726 glycoprotein (GP) gene sequences of the EBOV full-length genome obtained from West Africa from the 2014 outbreak, combined with 30 from earlier outbreaks between 1976 and 2008 were used to investigate the genetic divergence, evolutionary history, population dynamics, and selection pressure of EBOV among distinct epidemic waves...
October 21, 2016: Scientific Reports
Sajjad Karim, Hend Fakhri NourEldin, Heba Abusamra, Nada Salem, Elham Alhathli, Joel Dudley, Max Sanderford, Laura B Scheinfeldt, Sudhir Kumar
BACKGROUND: Genome-wide association studies (GWAS) have become a mainstay of biological research concerned with discovering genetic variation linked to phenotypic traits and diseases. Both discrete and continuous traits can be analyzed in GWAS to discover associations between single nucleotide polymorphisms (SNPs) and traits of interest. Associations are typically determined by estimating the significance of the statistical relationship between genetic loci and the given trait. However, the prioritization of bona fide, reproducible genetic associations from GWAS results remains a central challenge in identifying genomic loci underlying common complex diseases...
October 17, 2016: BMC Genomics
Sarah Thabet, Nada Souissi
The mycobacterial insertion sequence IS6110 proved crucial in deciphering tuberculosis (TB) transmission dynamics. This sequence was also shown to play an important role in the pathogenicity (transmission ability and/or virulence) of Mycobacterium tuberculosis, the main causative agent of TB in humans. In this study, we explored the usefulness of IS6110 and its potential as a phylogenetic/typing marker. We also analyzed the genetic polymorphism and evolutionary trends (selective pressure) of its transposase-encoding open reading frames (ORFs), A and B, using the maximum likelihood method...
October 20, 2016: Molecular Biology Reports
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