Evolution Of Other Organisms Research Articles

Viruses, immunity and evolution

In this article, the evolution of viruses is analyzed in terms of their complexity. It is shown that the evolution of viruses is a partially directed process. The participation of viruses and mobile genetic elements in the evolution of other organisms by integration into the genome is also an a priori directed process. The high variability of genomes (including the genes of antibodies), which differs by orders of magnitude for various viruses and their hosts, is not a random process but is the result of the action of a molecular genetic control system. Herein, a model of partially directed evolution of viruses is proposed.Throughout the life cycle of viruses, there is an interaction of complex biologically important molecules that cannot be explained on the basis of classic laws. The interaction of a virus with a cell is essentially a quantum event, including selective long-range action. Such an interaction can be interpreted as the “remote key-lock” principle. In this article, a model of the interaction of biologically important viral molecules with cellular molecules based on nontrivial quantum interactions is proposed. Experiments to test the model are also proposed.

The Pet127 protein is a mitochondrial 5'-to-3' exoribonuclease from the PD-(D/E)XK superfamily involved in RNA maturation and intron degradation in yeasts.

Pet127 is a mitochondrial protein found in multiple eukaryotic lineages, but absent from several taxa, including plants and animals. Distant homology suggests that it belongs to the divergent PD-(D/E)XK superfamily which includes various nucleases and related proteins. Earlier yeast genetics experiments suggest that it plays a nonessential role in RNA degradation and 5′ end processing. Our phylogenetic analysis suggests that it is a primordial eukaryotic invention that was retained in diverse groups, and independently lost several times in the evolution of other organisms. We demonstrate for the first time that the fungal Pet127 protein in vitro is a processive 5′-to-3′ exoribonuclease capable of digesting various substrates in a sequence nonspecific manner. Mutations in conserved residues essential in the PD-(D/E)XK superfamily active site abolish the activity of Pet127. Deletion of the PET127 gene in the pathogenic yeast Candida albicans results in a moderate increase in the steady-state levels of several transcripts and in accumulation of unspliced precursors and intronic sequences of three introns. Mutations in the active site residues result in a phenotype identical to that of the deletant, confirming that the exoribonuclease activity is related to the physiological role of the Pet127 protein. Pet127 activity is, however, not essential for maintaining the mitochondrial respiratory activity in C. albicans.

Human influences on evolution, and the ecological and societal consequences.

Humans have dramatic, diverse and far-reaching influences on the evolution of other organisms. Numerous examples of this human-induced contemporary evolution have been reported in a number of 'contexts', including hunting, harvesting, fishing, agriculture, medicine, climate change, pollution, eutrophication, urbanization, habitat fragmentation, biological invasions and emerging/disappearing diseases. Although numerous papers, journal special issues and books have addressed each of these contexts individually, the time has come to consider them together and thereby seek important similarities and differences. The goal of this special issue, and this introductory paper, is to promote and expand this nascent integration. We first develop predictions as to which human contexts might cause the strongest and most consistent directional selection, the greatest changes in evolutionary potential, the greatest genetic (as opposed to plastic) changes and the greatest effects on evolutionary diversification We then develop predictions as to the contexts where human-induced evolutionary changes might have the strongest effects on the population dynamics of the focal evolving species, the structure of their communities, the functions of their ecosystems and the benefits and costs for human societies. These qualitative predictions are intended as a rallying point for broader and more detailed future discussions of how human influences shape evolution, and how that evolution then influences species traits, biodiversity, ecosystems and humans.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.

The release of genetically engineered micro-organisms and viruses into the environment.

This review considers the reasons for, and research governing, the regulation and monitoring of genetically engineered micro-organisms and viruses (GEMs) released into the environment. The hazards associated with releasing GEMs into the environment are the creation and evolution of new pests and diseases, and damage to the ecosystem and non target species. The similarities and differences between GEMs and conventional micro-organisms are discussed in relation to risk assessment. Other issues covered include the persistence of micro-organisms in the environment, transgene dispersal to non-engineered microbes and other organisms, the effects of transgenes and transformation on fitness, and the evolution of pests and pathogens that are given or acquire transgenes. Areas requiring further research are identified and recommendations for risk assessment made. CONTENTS Summary 173 I. Introduction 173 II. A comparison of genetically engineered micro-organisms and viruses and conventional micro-organisms 174 III. Persistence in the environment 175 IV. Transfer of transgenes to other species 176 V. The evolution of genetically engineered micro-organisms and viruses and natural micro-organisms acquiring transgenes 178 VI. Damage to non-target species and ecosystem function 178 VII. Influences on the evolution of other organisms 179 VIII. Conclusions and discussion 180 References 181.

Molecular Biology of Rhodophyte and Chromophyte Plastids

Recent information on the plastid genes and genomes of rhodophyte (red algae) and chromophyte (yellow and brown algae) plastids are summarized. The plastid genomes of these algae contain many more genes than those of metaphyte (land plant) plastids, and the encoded proteins are involved in a much wider range of metabolic activities. Rhodophyte and chromophyte plastid genomes contain very few introns and maintain many ancestral gene operons, which suggests that they are more primitive than those of metaphytes. Hypotheses of plastid evolution (monophyletic or polyphyletic primary origins) are discussed and assessed. The data available at present support the idea that all plastids arose from a single endosymbiotic event that involved a cyanobacterium and a eukaryote host (monophyletic origin). Information from rhodophyte and chromophyte plastid genomes also provides insights into the evolution of other organisms. Finally, the implications for plastid metabolism that arise from the presence of several genes on rhodophyte and chromophyte plastid genomes are discussed.

Fungi from the Lower Devonian Rhynie Chert: Mycoparasitism

Several examples of mycoparasitism are described from the Lower Devonian (Siegenian) Rhynie chert. These fungal interactions include thick-walled chlamydospores and vesicles in which epibiotic fungi are attached to the outer surface of the spore. Other fossil spores are characterized by mycoparasites developing between the layers of the spore wall or within the lumen. The presence of callosities extending from the inner surface of some fossil spores demonstrates that the hosts were alive when parasitized. This response by the mycohost is identical to that found in certain modem mycoparasitic symbioses involving vesicular arbuscular mycorrhizae that are parasitized by various aquatic fungi. The presence of mycoparasitism in a 400-million-year-old ecosystem underscores the potential significance of the fungal genome early in the evolution of other organisms.

Fungi from the Lower Devonian Rhynie chert: My Coparasitism

Several examples of mycoparasitism are described from the Lower Devonian (Siegenian) Rhynie chert. These fungal interactions include thick‐walled chlamydospores and vesicles in which epibiotic fungi are attached to the outer surface of the spore. Other fossil spores are characterized by mycoparasites developing between the layers of the spore wall or within the lumen. The presence of callosities extending from the inner surface of some fossil spores demonstrates that the hosts were alive when parasitized. This response by the mycohost is identical to that found in certain modem mycoparasitic symbioses involving vesicular arbuscular mycorrhizae that are parasitized by various aquatic fungi. The presence of mycoparasitism in a 400‐million‐year‐old ecosystem underscores the potential significance of the fungal genome early in the evolution of other organisms.

Myrmecomorphy: Morphological and Behavioral Mimicry of Ants

The influence of ants on ecological communities is well documented by their quantitative effect on populations of other organisms (66, 176) and through the variety of relationships in which they are involved (166). Ants have influenced the evolution of other organisms in numerous ways: by being partners in symbiotic relationships, by providing exploitable resources, and by serving as models for the evolution of a remarkable variety of mimetic species (72). Myrmecomorphy, or the morphological and behavioral resem­ blance to ants, has evolved at least 70 times-IS times in the spiders (145), at least 10 times in the plant bugs (154), and 7 times in the staphylinid beetles (158). More than 2000 species of myrmecomorphic arthropods have been described thus far, belonging to over 200 genera in 54 families. Myrmecomorphy, or myrmecoidy (sensu 41, 42, 118), forms a subset of ant mimicry, which includes all species that resemble ants through convergence in morphological, behavioral, chemical, or textural characters. The other major group of ant-mimetic species are the myrmecophiles, or those arthropods that associate closely with ants, but do not necessarily resemble them (83). Unlike most myrmecomorphic species, myrmecophiles are typi­ cally convergent in chemical and/or textural characters that facilitate a close relationship with their ant models (71). Some myrmecophiles are also