scholarly journals Gene duplication as a mechanism of genomic adaptation to a changing environment

2012 ◽  
Vol 279 (1749) ◽  
pp. 5048-5057 ◽  
Author(s):  
Fyodor A. Kondrashov
Keyword(s):  
Environmental Conditions ◽  
Field Studies ◽  
Extensive Study ◽  
Gene Duplications ◽  
Substantial Fraction ◽  
Gene Copies ◽  
Number Variation ◽  
Genomic Adaptation ◽  
Selection For

A subject of extensive study in evolutionary theory has been the issue of how neutral, redundant copies can be maintained in the genome for long periods of time. Concurrently, examples of adaptive gene duplications to various environmental conditions in different species have been described. At this point, it is too early to tell whether or not a substantial fraction of gene copies have initially achieved fixation by positive selection for increased dosage. Nevertheless, enough examples have accumulated in the literature that such a possibility should be considered. Here, I review the recent examples of adaptive gene duplications and make an attempt to draw generalizations on what types of genes may be particularly prone to be selected for under certain environmental conditions. The identification of copy-number variation in ecological field studies of species adapting to stressful or novel environmental conditions may improve our understanding of gene duplications as a mechanism of adaptation and its relevance to the long-term persistence of gene duplications.

scholarly journals Transcriptional Mutagenesis Prevents Ribosomal DNA Deterioration: The Role of Duplications and Deletions

2019 ◽  
Vol 11 (11) ◽  
pp. 3207-3217
Author(s):  
Enrico Sandro Colizzi ◽  
Paulien Hogeweg
Keyword(s):  
Genome Stability ◽  
Evolutionary Dynamics ◽  
Point Mutations ◽  
Gene Duplications ◽  
Genetic Operators ◽  
Theory Of Evolution ◽  
Long Term Stability ◽  
Number Variation

Abstract Clashes between transcription and replication complexes can cause point mutations and chromosome rearrangements on heavily transcribed genes. In eukaryotic ribosomal RNA genes, the system that prevents transcription–replication conflicts also causes frequent copy number variation. Such fast mutational dynamics do not alter growth rates in yeast and are thus selectively near neutral. It was recently found that yeast regulates these mutations by means of a signaling cascade that depends on the availability of nutrients. Here, we investigate the long-term evolutionary effect of the mutational dynamics observed in yeast. We developed an in silico model of single-cell organisms whose genomes mutate more frequently when transcriptional load is larger. We show that mutations induced by high transcriptional load are beneficial when biased toward gene duplications and deletions: they decrease mutational load even though they increase the overall mutation rates. In contrast, genome stability is compromised when mutations are not biased toward gene duplications and deletions, even when mutations occur much less frequently. Taken together, our results show that the mutational dynamics observed in yeast are beneficial for the long-term stability of the genome and pave the way for a theory of evolution where genetic operators are themselves cause and outcome of the evolutionary dynamics.

Using laboratory incubations to predict the fate of pharmaceuticals in aquatic ecosystems

2018 ◽  
Vol 15 (8) ◽  
pp. 463 ◽  
Author(s):  
Johan Fahlman ◽  
Jerker Fick ◽  
Jan Karlsson ◽  
Micael Jonsson ◽  
Tomas Brodin ◽  
...  
Keyword(s):  
Field Study ◽  
Environmental Conditions ◽  
Aquatic Ecosystems ◽  
Laboratory Experiments ◽  
Field Studies ◽  
Small Scale ◽  
Removal Rates ◽  
Laboratory Conditions ◽  
Dissipation Rates

Environmental contextEnvironmental persistence of excreted pharmaceuticals in aquatic ecosystems is usually predicted using small-scale laboratory experiments assumed to simulate natural conditions. We studied five pharmaceuticals comparing their removal rates from water under laboratory conditions and under natural environmental conditions existing in a large pond. We found that the laboratory conditions did not fully capture the complexity within the pond, which led to different removal rates in the two systems. AbstractEnvironmental persistence is a key property when evaluating risks with excreted pharmaceuticals in aquatic ecosystems. Such persistence is typically predicted using small-scale laboratory incubations, but the variation in aquatic environments and scarcity of field studies to verify laboratory-based persistence estimates create uncertainties around the predictive power of these incubations. In this study we: (1) assess the persistence of five pharmaceuticals (diclofenac, diphenhydramine, hydroxyzine, trimethoprim and oxazepam) in laboratory experiments under different environmental conditions; and (2) use a three-month-long field study in an aquatic ecosystem to verify the laboratory-based persistence estimates. In our laboratory assays, we found that water temperature (TEMP), concentrations of organic solutes (TOC), presence of sediment (SED), and solar radiation (SOL) individually affected dissipation rates. Moreover, we identified rarely studied interaction effects between the treatments (i.e. SOL×SED and TEMP×SOL), which affected the persistence of the studied drugs. Half-lives obtained from the laboratory assays largely explained the dissipation rates during the first week of the field study. However, none of the applied models could accurately predict the long-term dissipation rates (month time-scale) from the water column. For example, the studied antibioticum (trimethoprim) and the anti-anxiety drug (oxazepam) remained at detectable levels in the aquatic environment long after (~150 days) our laboratory based models predicted complete dissipation. We conclude that small-scale laboratory incubations seem sufficient to approximate the short-term (i.e. within a week) dissipation rate of drugs in aquatic ecosystems. However, this simplistic approach does not capture interacting environmental processes that preserve a fraction of the dissolved pharmaceuticals for months in natural water bodies.

A simple device for field studies of animal activity

1983 ◽  
Vol 61 (6) ◽  
pp. 1401-1404 ◽  
Author(s):  
Lucius Stebbins ◽  
David Daisley
Keyword(s):  
Environmental Conditions ◽  
Field Studies ◽  
Simple Device ◽  
Electronic Components ◽  
Wide Range ◽  
Animal Activity

A reliable and simple device suitable for long-term recording of activity in natural environmental conditions is described. It is inexpensive to make, assembled with standard electronic components, and adaptable for a wide range of animal sizes. Instructions for assembly which can be interpreted with a minimum of electronics knowledge and parts lists with catalog numbers for a common Canadian electronics retailer are provided.

scholarly journals Mesophyll conductance in two cultivars of wheat (Triticum aestivum) grown in glacial to super-elevated [CO2]

2020 ◽  
Author(s):  
Eisrat Jahan ◽  
Peter C. Thomson ◽  
David T. Tissue
Keyword(s):  
Environmental Conditions ◽  
Mesophyll Conductance ◽  
Specific Mechanism ◽  
Physiological Basis ◽  
Breeding Programs ◽  
Cultivar Selection ◽  
Australian Wheat ◽  
Use Efficiency ◽  
Selection For

AbstractMesophyll conductance (gm) is an important factor limiting photosynthesis. However, gm response to long-term growth in variable [CO2] is not well understood, particularly in crop plants. Here, we grew two cultivars of wheat (Halberd and Cranbrook), known to differ in gm under current environmental conditions, in four [CO2] treatments: glacial (180 μmol mol−1), pre-industrial (280 μmol mol−1), current ambient (450 μmol mol−1) and super-elevated (1000 μmol mol−1) in well-watered and moderate water limitation conditions, to develop an evolutionary and future climate perspective on gm control of photosynthesis and water use efficiency (WUE). In the two wheat genotypes, gm increased with rising [CO2] from glacial to ambient [CO2], but declined at super-elevated [CO2]; however, the specific mechanism of gm response to [CO2] remains unclear. Although gm and gm/gsc (mesophyll conductance/stomatal conductance) were strongly associated with the variability of A and WUE, we found that plants with higher gm may increase A without increasing gsc, which increased WUE. These results may be useful to inform plant breeding programs and cultivar selection for Australian wheat under future environmental conditions.HighlightMesophyll conductance increased with increasing [CO2] from glacial to ambient CO2 levels, then declined at super-elevated CO2 for both well-watered and water-limited treatments. These responses of mesophyll conductance with varying [CO2] have a physiological basis.

SELECTION WORK TO IMPROVE PRODUCTIVE AND BREWING QUALITIES OF SPRING BARLEY

1970 ◽  
pp. 38-40
Author(s):  
О. V. Levakova ◽  
L. М. Eroshenko ◽  
А. N. Eroshenko
Keyword(s):  
Protein Content ◽  
Spring Barley ◽  
Humus Content ◽  
Stability Index ◽  
Field Studies ◽  
Climatic Conditions ◽  
Extract Content ◽  
Labile Phosphorus ◽  
Loam Soil

The article presents and analyzes data of competitive varietal testing of promising varieties and lines of spring barley for yield and brewing qualities. Field studies were conducted in 2014–2017 on dark gray forest heavy loam soil. Agrochemical parameters are total nitrogen – 0.24%, humus content in a layer of 0-40 cm (according to Tyurin) – 5.19%, hydrolysis nitrogen – 123.5 mg / kg, salt extract pH – 4.92 mg-eq / 100g; labile phosphorus - 34.6 mg / 100g, labile potassium – 20.0 mg / 100g. The forerunner is winter wheat. Meteorological conditions in the years of research differed from each other and from the average long-term value. Barley samples were assessed by the protein content in the grain (GOST 10846-91), extract content (GOST 12130-77), weight 1000 grains (GOST 10842-89). Ecological plasticity was determined by the method proposed by E.D. Nettevich, A.I. Morgunov and M.I. Maksimenko, stability index (Ľ) by A. A. Gryaznov, indicator of stability level (Puss) by E. D. Nettevich and A. I. Morgunov. The main measure for assessing quality indicators is protein content. Many other biochemical and technological features of grain depend on its level. The experimental data convincingly testify to the significant influence of the soil and climatic conditions on the yield and, especially, on the brewing qualities of barley in the conditions of the Central Region of the Nonchernozem Zone. According to the studied traits, new valuable varieties Nadezhny, Sir, Noble and selection lines 141 / 1-09 h 746, 23 / 1-10 h 784, distinguished by high adaptability and resistance to adverse environmental factors, have been identified.

Protected Areas: offering security to whom, when and where?

2016 ◽  
Vol 43 (2) ◽  
pp. 172-180 ◽  
Author(s):  
ALICE B. KELLY ◽  
A. CLARE GUPTA
Keyword(s):  
Protected Areas ◽  
Environmental Conditions ◽  
Protected Area ◽  
Spatial Scales ◽  
Local Population ◽  
Well Being ◽  
Economic Context ◽  
Term Management ◽  
Over Time

SUMMARYThis study considers the issue of security in the context of protected areas in Cameroon and Botswana. Though the literature on issues of security and well-being in relation to protected areas is extensive, there has been less discussion of how and in what ways these impacts and relationships can change over time, vary with space and differ across spatial scales. Looking at two very different historical trajectories, this study considers the heterogeneity of the security landscapes created by Waza and Chobe protected areas over time and space. This study finds that conservation measures that various subsets of the local population once considered to be ‘bad’ (e.g. violent, exclusionary protected area creation) may be construed as ‘good’ at different historical moments and geographical areas. Similarly, complacency or resignation to the presence of a park can be reversed by changing environmental conditions. Changes in the ways security (material and otherwise) has fluctuated within these two protected areas has implications for the long-term management and funding strategies of newly created and already existing protected areas today. This study suggests that parks must be adaptively managed not only for changing ecological conditions, but also for shifts in a protected area's social, political and economic context.

Analysis of high yielding maize production - a study based on a commercial crop

2008 ◽  
Vol 48 (3) ◽  
pp. 296 ◽  
Author(s):  
C. J. Birch ◽  
G. McLean ◽  
A. Sawers
Keyword(s):  
Retrospective Analysis ◽  
Environmental Conditions ◽  
Sowing Date ◽  
Plant Population ◽  
Higher Plant ◽  
Maize Crop ◽  
Wide Range ◽  
Commercial Crop ◽  
Reduced Temperature

This paper reports on the use of APSIM – Maize for retrospective analysis of performance of a high input, high yielding maize crop and analysis of predicted performance of maize grown with high inputs over the long-term (>100 years) for specified scenarios of environmental conditions (temperature and radiation) and agronomic inputs (sowing date, plant population, nitrogen fertiliser and irrigation) at Boort, Victoria, Australia. It uses a high yielding (17 400 kg/ha dry grain, 20 500 kg/ha at 15% water) commercial crop grown in 2004–05 as the basis of the study. Yield for the agronomic and environmental conditions of 2004–05 was predicted accurately, giving confidence that the model could be used for the detailed analyses undertaken. The analysis showed that the yield achieved was close to that possible with the conditions and agronomic inputs of 2004–05. Sowing dates during 21 September to 26 October had little effect on predicted yield, except when combined with reduced temperature. Single year and long-term analyses concluded that a higher plant population (11 plants/m2) is needed to optimise yield, but that slightly lower N and irrigation inputs are appropriate for the plant population used commercially (8.4 plants/m2). Also, compared with changes in agronomic inputs increases in temperature and/or radiation had relatively minor effects, except that reduced temperature reduces predicted yield substantially. This study provides an approach for the use of models for both retrospective analysis of crop performance and assessment of long-term variability of crop yield under a wide range of agronomic and environmental conditions.

scholarly journals A Genome-Wide Scan for Evidence of Selection in a Maize Population Under Long-Term Artificial Selection for Ear Number

Genetics ◽  
2013 ◽  
Vol 196 (3) ◽  
pp. 829-840 ◽  
Author(s):  
Timothy M. Beissinger ◽  
Candice N. Hirsch ◽  
Brieanne Vaillancourt ◽  
Shweta Deshpande ◽  
Kerrie Barry ◽  
...  
Keyword(s):  
Artificial Selection ◽  
Maize Population ◽  
Genome Wide ◽  
A Genome ◽  
Selection For ◽  
Ear Number ◽  
Genome Wide Scan

Natural inhibitors against potential targets of cyclooxygenase, lipoxygenase and leukotrienes

2021 ◽  
Vol 25 ◽  
Author(s):  
Rishita Dey ◽  
Sudatta Dey ◽  
Asmita Samadder ◽  
Anil Saxena ◽  
Sisir Nandi
Keyword(s):  
Rheumatoid Arthritis ◽  
Arachidonic Acid ◽  
Side Effects ◽  
Extensive Study ◽  
Alternative Medicines ◽  
Great Acceptance ◽  
Inflammatory Drugs ◽  
Lox Inhibitors ◽  
Natural Inhibitors

Background: The cyclooxygenase (COX) and lipoxygenase (LOX) enzymes catalyze the production of pain mediators like prostaglandins (PGs) and leukotrienes (LTs) respectively from arachidonic acid. Introduction: The COX and LOX enzyme modulators are responsible for the major PGs and LTs mediated complications like asthma, osteoarthritis, rheumatoid arthritis, cancer, Alzheimer’s disease, neuropathy and cardiovascular syndromes (CVS). Many synthetic nonsteroidal anti-inflammatory drugs (NSAIDs) used in the treatment have serious side effects like nausea, vomiting, hyperacidity, gastrointestinal ulcers, CVS, etc. Methods: The natural inhibitors of pain mediators have great acceptance worldwide due to fewer side effects on long-term uses. The present review is an extensive study of the advantages of plant-based vs synthetic inhibitors. Results: These natural COX and LOX inhibitors control inflammatory response without causing side-effect-related complicacy. Conclusion: Therefore, the natural COX and LOX inhibitors may be used as alternative medicines for the management of pain and inflammation due to their less toxicity and resistivity.

Sign in / Sign up

Export Citation Format

Share Document