scholarly journals Evolutionary design of regulatory control. II. Robust error-correcting feedback increases genetic and phenotypic variability

2018 ◽  
Author(s):  
Steven A. Frank
Keyword(s):  
Genetic Variability ◽  
Control Theory ◽  
Evolutionary Dynamics ◽  
Phenotypic Variability ◽  
Regulatory Control ◽  
Strong Increase ◽  
Evolutionary Analysis ◽  
High Heritability ◽  
Robust Systems ◽  
Different Levels

As systems become more robust against perturbations, they can compensate for greater sloppiness in the performance of their components. That robust compensation reduces the force of natural selection on the system’s components, leading to component decay. The paradoxical coupling of robustness and decay predicts that robust systems evolve cheaper, lower performing components, which accumulate greater mutational genetic variability and which have greater phenotypic stochasticity in trait expression. Previous work noted the paradox of robustness. However, no general theory for the evolutionary dynamics of system robustness and component decay has been developed. This article takes a first step by linking engineering control theory with the genetic theory of evolutionary dynamics. Control theory emphasizes error-correcting feedback as the single greatest principle in robust system design. Linking control theory to evolution leads to a theory for the evolutionary dynamics of error-correcting feedback, a unifying approach for the evolutionary analysis of robust systems. In this article, I study how, in theory, increasingly robust systems accumulate more genetic variability and greater stochasticity of expression in their components. The theory predicts different levels of variability between different regulatory control architectures and different levels of variability between different components within a particular regulatory control system. Those predictions provide a way to understand the accumulating data on genetic variability and single-cell stochasticity of gene expression. I also show that increasing robustness reduces the frequency of system failures associated with disease and, simultaneously, causes a strong increase in the heritability of disease. Thus, robust error correction in biological regulatory control may partly explain the puzzlingly high heritability of disease and, more generally, the surprisingly high heritability of fitness.

scholarly journals Evolutionary dynamics of bipartite begomoviruses revealed by complete genome analysis

2020 ◽  
Author(s):  
César A.D. Xavier ◽  
Márcio T. Godinho ◽  
Talita B. Mar ◽  
Camila G. Ferro ◽  
Osvaldo F.L. Sande ◽  
...  
Keyword(s):  
New World ◽  
Evolutionary Dynamics ◽  
Bipartite Begomoviruses ◽  
Evolutionary Analysis ◽  
Host Interactions ◽  
Coding Regions ◽  
Evolutionary Studies ◽  
Genetic Clusters ◽  
Complete Genome Analysis ◽  
Different Levels

ABSTRACTSeveral key evolutionary events marked the evolution of geminiviruses, culminating with the emergence of bipartite genomes represented by viruses classified in the genus Begomovirus. This genus represents the most abundant group of multipartite viruses, contributing significantly to the observed abundance of multipartite species in the virosphere. Although aspects related to virus-host interactions and evolutionary dynamics have been extensively studied, the bipartite nature of these viruses has been little explored in evolutionary studies. We performed a parallel evolutionary analysis of the DNA-A and DNA-B components of New World begomoviruses. A total of 239 full-length DNA-B sequences obtained in this study, combined with 292 DNA-A and 76 DNA-B sequences retrieved from GenBank, were analyzed. The results indicate that the DNA-A and DNA-B respond differentially to evolutionary processes, with the DNA-B being more permissive to variation and more prone to recombination than the DNA-A. Although a clear geographic segregation was observed for both components, differences in the genetic structure between DNA-A and DNA-B were also observed, with cognate components belonging to distinct genetic clusters. DNA-B coding regions evolve under the same selection pressures than DNA-A coding regions. Together, our results indicate an interplay between reassortment and recombination acting at different levels across distinct subpopulations and components.

scholarly journals Long-Term Cocirculation of Two Strains of Pepino Mosaic Virus in Tomato Crops and Its Effect on Population Genetic Variability

2020 ◽  
Vol 110 (1) ◽  
pp. 49-57 ◽  
Author(s):  
C. Alcaide ◽  
M. P. Rabadán ◽  
M. Juárez ◽  
P. Gómez
Keyword(s):  
Genetic Variability ◽  
Mosaic Virus ◽  
Evolutionary Dynamics ◽  
Geographical Area ◽  
Viral Fitness ◽  
Mixed Infections ◽  
Supporting Evidence ◽  
Pepino Mosaic Virus ◽  
Nucleotide Variability

Mixed viral infections are common in plants, and the evolutionary dynamics of viral populations may differ depending on whether the infection is caused by single or multiple viral strains. However, comparative studies of single and mixed infections using viral populations in comparable agricultural and geographical locations are lacking. Here, we monitored the occurrence of pepino mosaic virus (PepMV) in tomato crops in two major tomato-producing areas in Murcia (southeastern Spain), supporting evidence showing that PepMV disease-affected plants had single infections of the Chilean 2 (CH2) strain in one area and the other area exhibited long-term (13 years) coexistence of the CH2 and European (EU) strains. We hypothesized that circulating strains of PepMV might be modulating the differentiation between them and shaping the evolutionary dynamics of PepMV populations. Our phylogenetic analysis of 106 CH2 isolates randomly selected from both areas showed a remarkable divergence between the CH2 isolates, with increased nucleotide variability in the geographical area where both strains cocirculate. Furthermore, the potential virus–virus interaction was studied further by constructing six full-length infectious CH2 clones from both areas, and assessing their viral fitness in the presence and absence of an EU-type isolate. All CH2 clones showed decreased fitness in mixed infections and although complete genome sequencing indicated a nucleotide divergence of those CH2 clones by area, the magnitude of the fitness response was irrespective of the CH2 origin. Overall, these results suggest that although agroecological cropping practices may be particularly important for explaining the evolutionary dynamics of PepMV in tomato crops, the cocirculation of both strains may have implications on the genetic variability of PepMV populations.

scholarly journals Phenotypic Variability and Differences in the Drought Response of Norway Spruce Pendula and Pyramidalis Half-Sib Families

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 947
Author(s):  
Marius Budeanu ◽  
Ecaterina Nicoleta Apostol ◽  
Emanuel Besliu ◽  
Vlad Emil Crișan ◽  
Any Mary Petritan
Keyword(s):  
Growth Response ◽  
Phenotypic Variability ◽  
Ring Width ◽  
Comparative Trial ◽  
Field Trials ◽  
Selection Strategy ◽  
Drought Event ◽  
Recovery Capacity ◽  
High Heritability ◽  
Wood Resistance

In a changing climate, forest managers need to select productive and climate-change-resilient tree species and provenances. Therefore, assessing the growth response of provenances growing in field trials to climate provides useful information for identifying the more appropriate provenance or variety. To determine the genetic gain through selection of the most productive and resilient families and to decipher the role of crown forms of Norway spruces (Picea abies (L.) Karst.), we used 24 families with a classical crown (pyramidalis) and 24 with a narrow crown (pendula) from eight provenances, growing in a 25-year-old comparative trial. The annual wood characteristics (ring width and early- and latewood), the wood resistance (expressed by latewood proportion (LWP)), and the growth response to climate of the two spruce crown forms were investigated. No significant differences between the two spruce forms were found regarding the ring width characteristics. However, three pendula families of Stâna de Vale I provenance exhibited the highest LWP and could be included in a future selection strategy, the respective trait having also high heritability. Radial growth was positively and significantly correlated with previous September and current July precipitation and negatively with current June temperature. Both spruce forms showed good recovery capacity after a drought event.

scholarly journals Prevalence and genetic variability of tick-borne encephalitis virus in host-seeking Ixodes ricinus in northern Italy

2009 ◽  
Vol 90 (12) ◽  
pp. 2877-2883 ◽  
Author(s):  
Giovanna Carpi ◽  
Luigi Bertolotti ◽  
Sergio Rosati ◽  
Annapaola Rizzoli
Keyword(s):  
Genetic Variability ◽  
Ixodes Ricinus ◽  
Evolutionary Dynamics ◽  
Phylogenetic Analyses ◽  
Northern Italy ◽  
Nucleotide Sequence Analysis ◽  
Envelope Gene ◽  
North East ◽  
Tick Borne Encephalitis ◽  
Pcr Targeting

Tick-borne encephalitis (TBE) is a severe disease that has been endemic in north-east Italy since 1992. Over the past two decades, there has been an increase in the number of human cases reported in many European countries, including Italy. To assess the current TBE infection risk, questing ticks were collected from known TBE foci, as well as from a site in northern Italy where no human infections have been reported previously. A total of 1739 Ixodes ricinus (1485 nymphs and 254 adults) was collected and analysed for TBEV prevalence by a real-time RT-PCR targeting the 3′ untranslated region. Phylogenetic analyses of the partial envelope gene were conducted on two newly sequenced TBE virus (TBEV) strains and 28 previously published sequences to investigate the genealogical relationships of the circulating TBEV strains. These phylogenetic analyses confirmed a previous report that the European TBEV subtype is the only subtype circulating within the TBE foci in north-east Italy. Interestingly, nucleotide sequence analysis revealed a high degree of divergence (mean 2.54 %) between the TBEV strains recovered in the Italian province of Trento, despite the circulation of a single TBEV subtype. This elevated genetic variability within a single TBE focus may reflect local differences in the long-standing evolutionary dynamics of TBEV at this site relative to previously characterized sites, or more recent and continuous reintroduction of various TBEV strains.

scholarly journals Genotypic and phenotypic variability in mango (Mangifera indica L.)

2013 ◽  
Vol 37 (4) ◽  
pp. 683-690
Author(s):  
DAN Majumder ◽  
L Hassan ◽  
MA Rahim ◽  
MM Kabir
Keyword(s):  
Fruit Set ◽  
Phenotypic Variability ◽  
Mangifera Indica ◽  
Genetic Advance ◽  
Coefficients Of Variation ◽  
Shoot Number ◽  
Additive Gene ◽  
High Heritability ◽  
Almost All ◽  
Fruit Harvest

Sixty mango genotypes were studied to find out their variability, heritability, and genetic advance. Significant variations were observed in 20 characters. There were also considerable differences between the genotypic and the phenotypic coefficients of variation for almost all the characters which indicated the influence of environment on the expression of these traits. Among the studied characters, GCV and PCV were high for weight of harvested fruits per plant, % fruit harvest per inflorescence, % initial fruit set per inflorescence, number of fruits per plant and number of main branches per inflorescence. All the characters showed considerably high heritability which ranged from 56.21 to 98.24% and the genetic advance (as % of mean) was high for the maximum traits. High heritability coupled with high genetic advance was observed in weight of harvested fruits per plant, % initial fruit set per inflorescence, % of flowering shoot, number of inflorescences per shoot, percent fruit harvest per inflorescence, number of main branches per inflorescence, number of fruits per plant, number of inflorescences per shoot, plant height (cm), and percent perfect flowers which indicated that these characters were less influenced by environment confirming predominance of additive gene action and therefore, selection in favour of these characters would be feasible for yield improvement of mango. DOI: http://dx.doi.org/10.3329/bjar.v37i4.14393 Bangladesh J. Agril. Res. 37(4): 683-690, December 2012

scholarly journals Genetic and no genetic variability of two-year old seedlings of 13 hybrid plane half-sib lines

2005 ◽  
pp. 69-85 ◽  
Author(s):  
Radmila Knezevic ◽  
Mirjana Sijacic-Nikolic
Keyword(s):  
Genetic Variability ◽  
Environmental Conditions ◽  
Hybrid Sterility ◽  
Soil Humidity ◽  
Frequent Mutations ◽  
Different Levels ◽  
Partial Hybrid

This paper presents the results of the analysis of variability of 8 analyzed morph metric parameters in two-year old seedlings of 13 half-sib lines at different levels. The recorded genetic and no genetic variability is conditioned by numerous different factors. The important causes of genetic variability are: partial incompatibility of parent trees, partial hybrid sterility, predominant inbreeding, frequent mutations with the growth of parent trees, very abundant gene recombination's, etc. The causes of no genetic seedling variability are: external environmental conditions (soil humidity, conditions of cultivation, sylvotechnical interventions, etc) and the internal or the somatic environment of seedling.

Genetic diversity analysis of the Greek lentil (Lens culinaris) landrace ‘Eglouvis’ using morphological and molecular markers

2018 ◽  
Vol 16 (5) ◽  
pp. 469-477 ◽  
Author(s):  
Georgios F. Tsanakas ◽  
Photini V. Mylona ◽  
Katerina Koura ◽  
Anthoula Gleridou ◽  
Alexios N. Polidoros
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Morphological Analysis ◽  
Phenotypic Variability ◽  
Market Price ◽  
Genetic Distances ◽  
Reaction Products ◽  
Principal Coordinates Analysis ◽  
Principal Coordinates

AbstractThe Greek lentil landrace ‘Eglouvis’ is cultivated continuously at the Lefkada island for more than 400 years. It has great taste, high nutritional value and high market price. In the present study, we used morphological and molecular markers to estimate genetic diversity within the landrace. Morphological analysis was based on characteristics of the seed. Molecular analysis was performed using simple sequence repeat (SSR) molecular markers in a high-resolution melting (HRM) approach. ‘Samos’ and ‘Demetra’, two of the most widely cultivated commercial lentil varieties in Greece, were used for comparisons. Morphological analysis was performed with 584 seeds randomly selected from a lot. Analysis of seed dimensions and colour distributed the samples in different categories and highlighted the phenotypic variability in ‘Eglouvis’ lentil seeds. Genetic variability was estimated from 91 individual DNA samples with 11 SSR markers using HRM analysis. Genotyping was based upon the shape of the melting curves and the difference plots; all polymerase chain reaction products were also run on agarose gels. Genetic distances of individuals and principal coordinates analysis suggested that ‘Eglouvis’ landrace has a unique genetic background that significantly differs from ‘Samos’ and ‘Demetra’ and no overlapping could be detected. Genetic variability within the ‘Eglouvis’ landrace can be considered in targeted breeding programs as a significant phytogenetic resource of lentils in Greece.

scholarly journals Patterns of morphological diversification in giant Berberomeloe blister beetles (Coleoptera: Meloidae) reveal an unexpected taxonomic diversity concordant with mtDNA phylogenetic structure

2020 ◽  
Vol 189 (4) ◽  
pp. 1249-1312 ◽  
Author(s):  
Alberto Sánchez-Vialas ◽  
Mario García-París ◽  
José L Ruiz ◽  
Ernesto Recuero
Keyword(s):  
New Species ◽  
Genetic Variability ◽  
Phenotypic Variability ◽  
Morphological Diversity ◽  
Taxonomic Diversity ◽  
Molecular Data ◽  
Species Boundaries ◽  
Congeneric Species ◽  
Phylogenetic Structure ◽  
Morphological Diversification

Abstract Delimiting species boundaries is a complex challenge usually hindered by overlooked morphological diversification or misinterpretation of geographically structured phenotypic variability. Independent molecular data are extremely useful to characterize and understand such morphological diversity. Morphological and molecular variability of the non-phoretic and apterous, widely distributed, giant blister beetles of the genus Berberomeloe, were investigated within and between lineages across most of the distributional range of the genus. We used two mtDNA gene fragments to characterize genetic variability and to produce a time-calibrated phylogeny of the genus. Our results reveal several mitochondrial lineages, allopatrically, parapatrically and sympatrically distributed. Most clades are not distinguishable between each other based on morphometrics. However, no morphometric overlap is observed between two closely related clades, one of them occurring in sympatry with a distantly congeneric species (B. insignis), suggesting that sympatry could trigger morphological diversification. Although most species share a morphometric space, they can be morphologically identified by a combination of easily observed characteristic qualitative features. Based on the concordance between mtDNA clades and morphological units, we describe six new species of Berberomeloe (B. castuo sp. nov., B. comunero sp. nov., B. indalo sp. nov, B. yebli sp. nov., B. payoyo sp. nov. and B. tenebrosus sp. nov.), revalidate two taxa (B. maculifrons comb. nov. and B. laevigatus comb. nov.) and redefine B. majalis.

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