Search results for "selection"

Is group selection a factor modulating the virulence of RNA viruses?

1997

RNA viruses consist of populations of extremely high genetic heterogeneity called quasispecies. Based on theoretical considerations, it has been suggested that the unit of selection in such complex genetic populations is not the single viral particle but a set of genetically related particles which form the quasispecies. In the present study we carried out a set of experiments with the vesicular stomatitis virus (VSV) dealing with the evolution of life-history characters under selection acting at two factors either in the same or in opposite directions. The two factors at which selective pressure is applied are the individual and the group. We show evidence that group selection modulates th…

Rate of deleterious mutation and the distribution of its effects on fitness in vesicular stomatitis virus

1999

Despite their importance, the parameters describing the spontaneous deleterious mutation process have not been well described in many organisms. If mutations are important for the evolution of every living organism, their importance becomes critical in the case of RNA-based viruses, in which the frequency of mutation is orders of magnitude larger than in DNA-based organisms. The present work reports minimum estimates of the deleterious mutation rate, as well as the characterization of the distribution of deleterious mutational effects on the total fitness of the vesicular stomatitis virus (VSV). The estimates are based on mutation-accumulation experiments in which selection against deleteri…

The cost of replication fidelity in an RNA virus

2005

It is often argued that high mutation rates are advantageous for RNA viruses, because they confer elevated rates of adaptation. However, there is no direct evidence showing a positive correlation between mutation and adaptation rates among RNA viruses. Moreover, theoretical work does not argue in favor of this prediction. We used a series of vesicular stomatitis virus clones harboring single amino acid substitutions in the RNA polymerase to demonstrate that changes inducing enhanced fidelity paid a fitness cost, but that there was no positive correlation between mutation an adaptation rates. We demonstrate that the observed mutation rate in vesicular stomatitis virus can be explained by a t…

Sexual selection for genetic quality: disentangling the roles of male and female behaviour

2009

According to the good genes model of sexual selection, females choose males of good heritable genetic quality to obtain offspring with high fitness. However, better mating success of high-quality males can also be brought about by direct interference competition between males, or simply through elevated activity of high-quality males. We examined the roles of different processes leading to sexual selection for genetic quality in Drosophila montana. We manipulated genetic quality of male flies by inducing mutations with ionizing radiation. We then recorded the effects of inherited heterozygous mutations on several aspects of mating behaviour of males and females in two experiments. We found …

Does the VP1 gene of foot-and-mouth disease virus behave as a molecular clock?

1992

We have carried out a phylogenetic study of the evolution of the VP1 gene sequence from different serological types and subtypes of foot-and-mouth disease virus (FMDV). The maximum-likelihood method developed by Hasegawa and co-workers (Hasegawa et al. 1985) for the estimation of evolutionary parameters and branching dates has been used to decide between alternative models of evolution: constant versus variable rates. The results obtained indicate that a constant rate model, i.e., a molecular clock, seems to be the most plausible one. However, additional information suggests the possibility that the appearance of serotype CS has been accompanied by an episode of rapid evolution (Villaverde …

Inbreeding depression in intraspecific metabolic scaling

2013

Metabolic scaling (i.e., the relationship between the size and metabolic rate of organisms) has been suggested to explain a large variety of biological patterns from individual growth to species diversity. However, considerable disagreement remains regarding the underlying causes of metabolic scaling patterns, and what these patterns are. As in all biology, understanding metabolic scaling will require understanding its evolution by natural selection. We searched for evidence of natural selection on metabolic scaling indirectly by manipulating the genetic quality of male and female Drosophila montana flies with induced mutations and inbreeding, building on the notion that mutations and inbre…

2019

Codon composition, GC content and local RNA secondary structures can have a profound effect on gene expression, and mutations affecting these parameters, even though they do not alter the protein sequence, are not neutral in terms of selection. Although evidence exists that, in some cases, selection favours more stable RNA secondary structures, we currently lack a concrete idea of how many genes are affected within a species, and whether this is a universal phenomenon in nature. We searched for signs of structural selection in a global manner, analysing a set of 1 million coding sequences from 73 species representing all domains of life, as well as viruses, by means of our newly developed s…

Natural Selection Footprint in Novel Coronavirus: A Genomic Perspective of SARS-COV2 Pandemic and Hypothesis for Peptide-Based Vaccine

2021

We retrospective analyzed in silico the binding affinity of SARS-CoV-2 peptides to MHC class I HLA-A, -B, and –C molecules in different countries with high and low morbidity and mortality rates. We used bioinformatics approach to screen 18260 SARS-CoV-2 epitopes that have significant affinity for different MHC class I alleles and found approximately five thousand predicted nonamers to bind different alleles. Those predicted epitopes show different significant affinity for frequently occurring MHC I alleles. regarding to HLA frequencies within different populations that can vary due to differences in their evolutionary histories, we showed that those alleles have different correlation with S…

Males Benefit from Mating with Outbred Females in Drosophila littoralis: Male Choice for Female Genetic Quality?

2015

The evolution and expression of mate choice behaviour in either sex depends on the sex-specific combination of mating costs, benefits of choice and constraints on choice. If the benefits of choice are larger for one sex, we would expect that sex to be choosier, assuming that the mating costs and constraints on choice are equal between sexes. Because deliberate inbreeding is a powerful genetic method for experimental manipulation of the quality of study organisms, we tested the effects of both male and female inbreeding on egg and offspring production in Drosophila littoralis. Female inbreeding significantly reduced offspring production (mostly due to lower egg-to-adult viability), whereas m…

Similar Performance of Diploid and Haploid Males in an Ant Species without Inbreeding Avoidance

2013

AbstractUnder haplodiploidy, a characteristic trait of all Hymenoptera, femalesdevelop from fertilised eggs, and males from unfertilised ones. Males aretherefore typically haploid. Yet, inbreeding can lead to the production ofdiploid males that often fail in development, are sterile or are of lowerfertility. In most Hymenoptera, inbreeding is avoided by dispersal flightsof one or both sexes, leading to low diploid male loads. We investigatedcauses for the production of diploid males and their performance in ahighly inbred social Hymenopteran species. In the ant Hypoponera opacior,inbreeding occurs between wingless sexuals, which mate within themother nest, whereas winged sexuals outbreed dur…