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Достижения молекулярной биологии на современном этапе
Adams R.I., Hadly E.A. Genetic diversity within vertebrate species is greater at lower latitudes // Evol. Ecol. 2013. Vol. 27, № 1. P. 133–143.
The latitudinal gradient of species diversity is one of the oldest recognized patterns in biology. While the cause of the pattern remains debated, the global signal of greater diversity toward the tropics is widely established. Whether the pattern holds for genetic diversity within species, however, has received much less attention. We examine latitudinal variation of intraspecific genetic diversity by contrasting nucleotide distance within low- and high-latitude animal groups. Using mitochondrial DNA markers across 72 vertebrate species that together span six continents, two oceans, and 129 degrees of latitude, we found significantly greater genetic diversity at low latitudes within mammalian species, and trends consistent with this pattern in reptiles, amphibians, fish, and birds. The signal held even after removing species whose current geographic ranges include areas recently covered by glaciers during the late Pleistocene and which presumably have experienced colonization bottlenecks in high latitudes. Higher genetic diversity within species was found at low latitudes also for genera that do not possess higher species richness toward the tropics. Moreover, examination of a subset of species with sufficient sampling across a broad geographic range revealed that genetic variation demonstrates a typical gradient, with mid-latitude populations intermediate in genetic diversity between high and low latitude ones. These results broaden the pattern of the global latitudinal diversity gradient, to now include variation within species. These results are also concordant with other studies indicating that low latitude populations and species are on different evolutionary trajectories than high latitude ones, and we speculate that higher rates of evolution toward the equator are driving the pattern for genetic diversity within species.
Chinchar V.G., Yu K.H., Jancovich J.K. The Molecular Biology of Frog Virus 3 and other Iridoviruses Infecting Cold-Blooded Vertebrates // Viruses-Basel. 2011. Vol. 3, № 10. P. 1959–1985.
Frog virus 3 (FV3) is the best characterized member of the family Iridoviridae. FV3 study has provided insights into the replication of other family members, and has served as a model of viral transcription, genome replication, and virus-mediated host-shutoff. Although the broad outlines of FV3 replication have been elucidated, the precise roles of most viral proteins remain unknown. Current studies using knock down (KD) mediated by antisense morpholino oligonucleotides (asMO) and small, interfering RNAs (siRNA), knock out (KO) following replacement of the targeted gene with a selectable marker by homologous recombination, ectopic viral gene expression, and recombinant viral proteins have enabled researchers to systematically ascertain replicative- and virulence-related gene functions. In addition, the application of molecular tools to ecological studies is providing novel ways for field biologists to identify potential pathogens, quantify infections, and trace the evolution of ecologically important viral species. In this review, we summarize current studies using not only FV3, but also other iridoviruses infecting ectotherms. As described below, general principles ascertained using FV3 served as a model for the family, and studies utilizing other ranaviruses and megalocytiviruses have confirmed and extended our understanding of iridovirus replication. Collectively, these and future efforts will elucidate molecular events in viral replication, intrinsic and extrinsic factors that contribute to disease outbreaks, and the role of the host immune system in protection from disease.
Ellegren H. Genome sequencing and population genomics in non-model organisms // Trends Ecol. Evol. 2014. Vol. 29, № 1. P. 51–63.
High-throughput sequencing technologies are revolutionizing the life sciences. The past 12 months have seen a burst of genome sequences from non-model organisms, in each case representing a fundamental source of data of significant importance to biological research. This has bearing on several aspects of evolutionary biology, and we are now beginning to see patterns emerging from these studies. These include significant heterogeneity in the rate of recombination that affects adaptive evolution and base composition, the role of population size in adaptive evolution, and the importance of expansion of gene families in lineage-specific adaptation. Moreover, resequencing of population samples (population genomics) has enabled the identification of the genetic basis of critical phenotypes and cast light on the landscape of genomic divergence during speciation.
Evans B.J. et al. Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa // PLoS One. 2015. Vol. 10, № 12. P. e0142823.
African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon) to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana) and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups).
Fagotto F. et al. A Molecular Base for Cell Sorting at Embryonic Boundaries: Contact Inhibition of Cadherin Adhesion by Ephrin/Eph-Dependent Contractility // Dev. Cell. 2013. Vol. 27, № 1. P. 72–87.
The mechanism responsible for subdividing the embryo into individual tissues is a fundamental, yet still poorly understood, question in developmental biology. Various general hypotheses have been proposed, involving differences in cell adhesion, contractility, or contact-mediated repulsion. However, the key parameter in tissue separation, i.e., the regulation of cadherin-based adhesion at the boundary, has not yet been investigated. We show that cadherin clustering is specifically inhibited at the vertebrate notochord-presomitic mesoderm boundary, preventing formation of adhesive bonds between cells of the two different types. This local regulation depends on differentially expressed ephrins and Eph receptors, which increase cell contractility and generate a membrane blebbing-like behavior along the boundary. Inhibiting myosin activity is sufficient to induce cadherin clustering and formation of stable contacts across the boundary, causing notochord and presomitic tissues to fuse. Local inhibition of cadherin adhesion explains how sharp separation can be achieved in response to cell-cell contact signals.
Goldbeter A. et al. Systems biology of cellular rhythms // FEBS Lett. 2012. Vol. 586, № 18. P. 2955–2965.
Rhythms abound in biological systems, particularly at the cellular level where they originate from the feedback loops present in regulatory networks. Cellular rhythms can be investigated both by experimental and modeling approaches, and thus represent a prototypic field of research for systems biology. They have also become a major topic in synthetic biology. We review advances in the study of cellular rhythms of biochemical rather than electrical origin by considering a variety of oscillatory processes such as Ca++ oscillations, circadian rhythms, the segmentation clock, oscillations in p53 and NF-kappa B, synthetic oscillators, and the oscillatory dynamics of cyclin-dependent kinases driving the cell cycle. Finally we discuss the coupling between cellular rhythms and their robustness with respect to molecular noise. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.
Hori T., Fukagawa T. Establishment of the vertebrate kinetochores // Chromosome Res. 2012. Vol. 20, № 5. P. 547–561.
The centromere is essential for accurate chromosome segregation during mitosis and meiosis to achieve transmission of genetic information to daughter cells. To facilitate accurate chromosome segregation, the centromere serves several specific functions, including microtubule binding, spindle-checkpoint control, and sister chromatid cohesion. The kinetochore is formed on the centromere to achieve these functions. To understand kinetochore structure and function, it is critical to identify the protein components of the kinetochore and characterize the functional properties of each component. Here, we review recent progress with regard to the molecular architecture of the kinetochore and discuss the future directions for centromere biology.
Hosokawa Y. et al. Photoporation of Biomolecules into Single Cells in Living Vertebrate Embryos Induced by a Femtosecond Laser Amplifier // PLoS One. 2011. Vol. 6, № 11. P. e27677.
Introduction of biomolecules into cells in living animals is one of the most important techniques in molecular and developmental biology research, and has potentially broad biomedical implications. Here we report that biomolecules can be introduced into single cells in living vertebrate embryos by photoporation using a femtosecond laser amplifier with a high pulse energy and a low repetition rate. First, we confirmed the efficiency of this photoporation technique by introducing dextran, morpholino oligonucleotides, or DNA plasmids into targeted single cells of zebrafish, chick, shark, and mouse embryos. Second, we demonstrated that femtosecond laser irradiation efficiently delivered DNA plasmids into single neurons of chick embryos. Finally, we successfully manipulated the fate of single neurons in zebrafish embryos by delivering mRNA. Our observations suggest that photoporation using a femtosecond laser with a high pulse energy and low repetition rate offers a novel way to manipulate the function(s) of individual cells in a wide range of vertebrate embryos by introduction of selected biomolecules.
Kartavtsev Y.P. Sequence divergence at mitochondrial genes in animals: Applicability of DNA data in genetics of speciation and molecular phylogenetics // Mar. Genom. 2011. Vol. 4, № 2. P. 71–81.
Nucleotide diversity estimates for the genes Cyt-b (cytochrome b) and Co-1 (cytochrome oxidase 1) are analyzed. Genetic divergence of populations (1) and taxa of different rank, such as subspecies, semispecies or/and sibling species (2), species within a genus (3), species from different genera within a family (4), and species from separate families within an order (5) have been compared using a database of p-distances and similar measures. Empirical data for 20,731 vertebrate and invertebrate animal species reveal various and increasing levels of genetic divergence of the sequences of the two genes. Cyt-b and Co-1, in the five groups compared. Mean unweighted scores of p-distances (%) for five groups are: Cyt-b (1) 1.38 +/- 0.30, (2) 5.10 +/- 0.91, (3) 10.31 +/- 0.93, (4) 17.86 +/- 1.36, (5) 26.36 +/- 3.88 and Co-1 (1) 0.89 +/- 0.16, (2) 3.78 +/- 1.18, (3) 11.06 +/- 0.53, (4) 16.60 +/- 0.69, (5) 20.57 +/- 0.40. These estimates testify to the applicability of p-distance for most intraspecies and interspecies comparisons of genetic divergence up to the order level for the two genes compared. The results of the analysis of the nucleotide divergence within species and higher taxa of animals suggest that a phyletic evolution in animals is likely to prevail at the molecular level, and speciation mainly corresponds to the geographic or divergence mode (type D1). The prevalence of the D1 speciation mode does not mean that other modes are absent. At least seven possible modes of speciation are considered. The approach suggested that allows recognize the speciation modes formally with the operational genetic criteria. Such approach may help to solve a key problem of the biological species concept, i.e. the lack of ability to monitor in most cases the reproductive isolation barriers between species. (C) 2011 Elsevier B.V. All rights reserved.
Lee Y., Dawson V.L., Dawson T.M. Animal Models of Parkinson’s Disease: Vertebrate Genetics // Cold Spring Harb. Perspect. Med. 2012. Vol. 2, № 10. P. a009324.
Parkinson's disease (PD) is a complex genetic disorder that is associated with environmental risk factors and aging. Vertebrate genetic models, especially mice, have aided the study of autosomal-dominant and autosomal-recessive PD. Mice are capable of showing a broad range of phenotypes and, coupled with their conserved genetic and anatomical structures, provide unparalleled molecular and pathological tools to model human disease. These models used in combination with aging and PD-associated toxins have expanded our understanding of PD pathogenesis. Attempts to refine PD animal models using conditional approaches have yielded in vivo nigrostriatal degeneration that is instructive in ordering pathogenic signaling and in developing therapeutic strategies to cure or halt the disease. Here, we provide an overview of the generation and characterization of transgenic and knockout mice used to study PD followed by a review of the molecular insights that have been gleaned from current PD mouse models. Finally, potential approaches to refine and improve current models are discussed.
Lin Y.G. et al. Molecular Evolutionary Analysis of Vertebrate Transducins: A Role for Amino Acid Variation in Photoreceptor Deactivation // J. Mol. Evol. 2013. Vol. 77, № 5–6. P. 231–245.
Transducin is a heterotrimeric G protein that plays a critical role in phototransduction in the rod and cone photoreceptor cells of the vertebrate retina. Rods, highly sensitive cells that recover from photoactivation slowly, underlie dim-light vision, whereas cones are less sensitive, recover more quickly, and underlie bright-light vision. Transducin deactivation is a critical step in photoreceptor recovery and may underlie the functional distinction between rods and cones. Rods and cones possess distinct transducin alpha subunits, yet they share a common deactivation mechanism, the GTPase activating protein (GAP) complex. Here, we used codon models to examine patterns of sequence evolution in rod (GNAT1) and cone (GNAT2) alpha subunits. Our results indicate that purifying selection is the dominant force shaping GNAT1 and GNAT2 evolution, but that GNAT2 has additionally been subject to positive selection operating at multiple phylogenetic scales; phylogeny-wide analysis identified several sites in the GNAT2 helical domain as having substantially elevated dN/dS estimates, and branch-site analysis identified several nearby sites as targets of strong positive selection during early vertebrate history. Examination of aligned GNAT and GAP complex crystal structures revealed steric clashes between several positively selected sites and the deactivating GAP complex. This suggests that GNAT2 sequence variation could play an important role in adaptive evolution of the vertebrate visual system via effects on photoreceptor deactivation kinetics and provides an alternative perspective to previous work that focused instead on the effect of GAP complex concentration. Our findings thus further the understanding of the molecular biology, physiology, and evolution of vertebrate visual systems.
Mendoza A.M. et al. A likelihood inference of historical biogeography in the world’s most diverse terrestrial vertebrate genus: Diversification of direct-developing frogs (Craugastoridae: Pristimantis) across the Neotropics // Mol. Phylogenet. Evol. 2015. Vol. 85. P. 50–58.
The geology of the northern Andean region has driven the evolutionary history of Neotropical fauna through the creation of barriers and connections that have resulted in speciation and dispersal events, respectively. One of the most conspicuous groups of anuran fauna in the Andes and surrounding areas is the direct-developing species of the genus Pristimantis. We investigated the molecular phylogenetic placement of 12 species from the montane Andes of Colombia in a broader geographical context with a new genus-level phylogeny in order to identify the role of Andean orogeny over the last 40 million years and the effect of elevational differences in diversification of Pristimantis. We examined the biogeographic history of the genus using ancestral range reconstruction by biogeographic regions and elevational ranges. We recognized the middle elevational band (between 1000 and 3000 m) in the Northwestern Andes region of Colombia and Ecuador as a focal point for the origin and radiation of Pristimantis species. Additionally, we found several Andean migrations toward new habitats in Central Andes and Merida Andes for some species groups. We suggest that the paleogeological changes in the Northwestern Andes were the main promoter of speciation in Pristimantis, and may have served as a corridor for the dispersion of lowland species. (C) 2015 Elsevier Inc. All rights reserved.
Riadi G. et al. Towards the bridging of molecular genetics data across Xenopus species // BMC Genomics. 2016. Vol. 17. P. 161.
Background: The clawed African frog Xenopus laevis has been one of the main vertebrate models for studies in developmental biology. However, for genetic studies, Xenopus tropicalis has been the experimental model of choice because it shorter life cycle and due to a more tractable genome that does not result from genome duplication as in the case of X. laevis. Today, although still organized in a large number of scaffolds, nearly 85 % of X. tropicalis and 89 % of X. laevis genomes have been sequenced. There is expectation for a comparative physical map that can be used as a Rosetta Stone between X. laevis genetic studies and X. tropicalis genomic research. Results: In this work, we have mapped using coarse-grained alignment the 18 chromosomes of X. laevis, release 9.1, on the 10 reference scaffolds representing the haploid genome of X. tropicalis, release 9.0. After validating the mapping with theoretical data, and estimating reference averages of genome sequence identity, 37 to 44 % between the two species, we have carried out a synteny analysis for 2,112 orthologous genes. We found that 99.6 % of genes are in the same organization. Conclusions: Taken together, our results make possible to establish the correspondence between 62 and 65.5 % of both genomes, percentage of identity, synteny and automatic annotation of transcripts of both species, providing a new and more comprehensive tool for comparative analysis of these two species, by allowing to bridge molecular genetics data among them.
Stauber M. et al. Modifying transcript lengths of cycling mouse segmentation genes // Mech. Dev. 2012. Vol. 129, № 1–4. P. 61–72.
Regular production of somites, precursors of the axial skeleton and attached muscles is controlled by a molecular oscillator, the segmentation clock, which drives cyclic transcription of target genes in the unsegmented presomitic mesoderm (PSM). The clock is based on a negative feedback loop which generates pulses of transcription that oscillate with the same periodicity as somite formation. Mutants in several oscillating genes including the Notch pathway gene Lunatic fringe (Lfng) and the Notch target Hes7, result in defective somitogenesis and disorganised axial skeletons. Both genes encode negative regulators of Notch signalling output, but it is not yet clear if they are just secondary clock targets or if they encode components of a primary, pacemaker oscillator. In this paper, we try to identify components in the primary oscillator by manipulating delays in the feedback circuitry. We characterise recombinant mice in which Lfng and Hes7 introns are lengthened in order to delay mRNA production. Lengthening the third Hes7 intron by 10 or 20 kb disrupts accurate RNA splicing and inactivates the gene. Lfng expression and activity is normal in mice whose Lfng is lengthened by 10 kb, but no effects on segmentation are evident. We discuss these results in terms of the relative contributions of transcriptional and post-transcriptional delays towards defining the pace of segmentation, and of alternative strategies for manipulating the period of the clock. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
Szabo R., Bugge T.H. Membrane-Anchored Serine Proteases in Vertebrate Cell and Developmental Biology // Annual Review of Cell and Developmental Biology, Vol 27 / ed. Schekman R., Goldstein L., Lehmann R. Palo Alto: Annual Reviews, 2011. Vol. 27. P. 213–235.
Analysis of vertebrate genome sequences at the turn of the millennium revealed that a vastly larger repertoire of enzymes execute proteolytic cleavage reactions within the pericellular and extracellular environments than was anticipated from biochemical and molecular analysis. Most unexpected was the unveiling of an entire new family of structurally unique multidomain serine proteases that are anchored directly to the plasma membrane. Unlike secreted serine proteases, which function primarily in tissue repair, immunity, and nutrient uptake, these membrane-anchored serine proteases regulate fundamental cellular and developmental processes, including tissue morphogenesis, epithelial barrier function, ion and water transport, cellular iron export, and fertilization. Here the cellular and developmental biology of this fascinating new group of proteases is reviewed. Particularly highlighted is how the study of membrane-anchored serine proteases has expanded our knowledge of the range of physiological processes that require regulated proteolysis at the cell surface.
Torday J.S. Evolution and Cell Physiology. Cell signaling is all of biology // Am. J. Physiol.-Cell Physiol. 2013. Vol. 305, № 7. P. C682–C689.
I hypothesize that the First Principles of Physiology (FPPs) were co-opted during the vertebrate transition from water to land, beginning with the acquisition of cholesterol by eukaryotes, facilitating unicellular evolution over the course of the first 4.5 billion years of the Earth's history, in service to the reduction in intracellular entropy, far from equilibrium. That mechanism was perpetuated by the advent of cholesterol in the cell membrane of unicellular eukaryotes, ultimately giving rise to the metazoan homologs of the gut, lung, kidney, skin, bone, and brain. Parathyroid hormone-related protein (PTHrP), whose cognate receptor underwent a gene duplication during the transition from fish to amphibians, facilitated gas exchange for the water-to-land transition, since PTHrP is necessary for the formation of lung alveoli: deletion of the PTHrP gene in mice causes the offspring to die within a few minutes of birth due to the absence of alveoli. Moreover, PTHrP is central to the development and homeostasis of the kidney, skin, gut, bone, and brain. Therefore, duplication of the PTHrP receptor gene is predicted to have facilitated the molecular evolution of all the necessary traits for land habitation through a common cellular and molecular motif. Subsequent duplication of the beta-adrenergic receptor gene permitted blood pressure control within the lung microvasculature, allowing further evolution of the lung by increasing its surface area. I propose that such gene duplications were the result of shear stress on the microvasculature, locally generating radical oxygen species that caused DNA mutations, giving rise to duplication of the PTHrP and beta-adrenergic receptor genes. I propose that one can determine the FPPs by systematically tracing the molecular homologies between the lung, skin, kidney, gut, bone, and brain across development, phylogeny, and pathophysiology as a type of "reverse evolution." By tracing such relationships back to unicellular organisms, one can use the underlying principles to predict homeostatic failure as disease, thereby also potentially forming the basis for maneuvers that can treat or even prevent such failure.
Varmuza S., Miri K. What does genetics tell us about imprinting and the placenta connection? // Cell. Mol. Life Sci. 2015. Vol. 72, № 1. P. 51–72.
Genomic imprinting is an epigenetic gene silencing phenomenon that is specific to eutherians in the vertebrate lineage. The acquisition of both placentation and genomic imprinting has spurred interest in the possible evolutionary link for many years. In this review we examine the genetic evidence and find that while many imprinted domains are anchored by genes required for proper placenta development in a parent of origin fashion, an equal number of imprinted genes have no apparent function that depends on imprinting. Examination of recent data from studies of molecular and genetic mechanisms points to a maternal control of the selection and maintenance of imprint marks, reinforcing the importance of the oocyte in the healthy development of the placenta and fetus.
Xia X. DAMBE5: A Comprehensive Software Package for Data Analysis in Molecular Biology and Evolution // Mol. Biol. Evol. 2013. Vol. 30, № 7. P. 1720–1728.
Since its first release in 2001 as mainly a software package for phylogenetic analysis, data analysis for molecular biology and evolution (DAMBE) has gained many new functions that may be classified into six categories: 1) sequence retrieval, editing, manipulation, and conversion among more than 20 standard sequence formats including MEGA, NEXUS, PHYLIP, GenBank, and the new NeXML format for interoperability, 2) motif characterization and discovery functions such as position weight matrix and Gibbs sampler, 3) descriptive genomic analysis tools with improved versions of codon adaptation index, effective number of codons, protein isoelectric point profiling, RNA and protein secondary structure prediction and calculation of minimum folding energy, and genomic skew plots with optimized window size, 4) molecular phylogenetics including sequence alignment, testing substitution saturation, distance-based, maximum parsimony, and maximum-likelihood methods for tree reconstructions, testing the molecular clock hypothesis with either a phylogeny or with relative-rate tests, dating gene duplication and speciation events, choosing the best-fit substitution models, and estimating rate heterogeneity over sites, 5) phylogeny-based comparative methods for continuous and discrete variables, and 6) graphic functions including secondary structure display, optimized skew plot, hydrophobicity plot, and many other plots of amino acid properties along a protein sequence, tree display and drawing by dragging nodes to each other, and visual searching of the maximum parsimony tree. DAMBE features a graphic, user-friendly, and intuitive interface and is freely available from ext-link-type="uri" xlink:href="http://dambe.bio.uottawa.ca" xmlns:xlink="http://www.w3.org/1999/xlink">http://dambe.bio.uottawa.ca (last accessed April 16, 2013).
Zhang H.-H. et al. Recurrent Horizontal Transfers of Chapaev Transposons in Diverse Invertebrate and Vertebrate Animals // Genome Biol. Evol. 2014. Vol. 6, № 6. P. 1375–1386.
Horizontal transfer (HT) of a transposable element (TE) into a new genome is regarded as an important force to drive genome variation and biological innovation. In addition, HT also plays an important role in the persistence of TEs in eukaryotic genomes. Here, we provide the first documented example for the repeated HT of three families of Chapaev transposons in a wide range of animal species, including mammals, reptiles, jawed fishes, lampreys, insects, and in an insect bracovirus. Multiple alignments of the Chapaev transposons identified in these species revealed extremely high levels of nucleotide sequence identity (79-99%), which are inconsistent with vertical evolution given the deep divergence time separating these host species. Rather, the discontinuous distribution amongst species and lack of purifying selection acting on these transposons strongly suggest that they were independently and horizontally transferred into these species lineages. The detection of Chapaev transposons in an insect bracovirus indicated that these viruses might act as a possible vector for the horizontal spread of Chapaev transposons. One of the Chapaev families was also shared by lampreys and some of their common hosts (such as sturgeon and paddlefish), which suggested that parasite-host interaction might facilitate HTs.
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