Showing papers in "Nature Reviews Genetics in 2004"
TL;DR: This work states that rapid advances in network biology indicate that cellular networks are governed by universal laws and offer a new conceptual framework that could potentially revolutionize the view of biology and disease pathologies in the twenty-first century.
Abstract: A key aim of postgenomic biomedical research is to systematically catalogue all molecules and their interactions within a living cell. There is a clear need to understand how these molecules and the interactions between them determine the function of this enormously complex machinery, both in isolation and when surrounded by other cells. Rapid advances in network biology indicate that cellular networks are governed by universal laws and offer a new conceptual framework that could potentially revolutionize our view of biology and disease pathologies in the twenty-first century.
7,475 citations
TL;DR: Two founding members of the microRNA family were originally identified in Caenorhabditis elegans as genes that were required for the timed regulation of developmental events and indicate the existence of multiple RISCs that carry out related but specific biological functions.
Abstract: MicroRNAs are a family of small, non-coding RNAs that regulate gene expression in a sequence-specific manner. The two founding members of the microRNA family were originally identified in Caenorhabditis elegans as genes that were required for the timed regulation of developmental events. Since then, hundreds of microRNAs have been identified in almost all metazoan genomes, including worms, flies, plants and mammals. MicroRNAs have diverse expression patterns and might regulate various developmental and physiological processes. Their discovery adds a new dimension to our understanding of complex gene regulatory networks.
6,282 citations
TL;DR: A large number of microRNAs have been identified in almost all metazoan genomes, including worms, flies, plants and mammals, and their discovery adds a new dimension to the understanding of complex gene regulatory networks.
Abstract: Nature Reviews Genetics 5, 522–531 (2004) In figure 2, the orientation of some RNA structures was incorrect. The corrected version is shown below. This correction has been made to the online enhanced text and PDF version of this review.
2,555 citations
TL;DR: Few genetic markers, if any, have found such widespread use as microsatellites, or simple/short tandem repeats, but features such as hypervariability and ubiquitous occurrence explain their usefulness, but these features also pose several questions.
Abstract: Few genetic markers, if any, have found such widespread use as microsatellites, or simple/short tandem repeats. Features such as hypervariability and ubiquitous occurrence explain their usefulness, but these features also pose several questions. For example, why are microsatellites so abundant, why are they so polymorphic and by what mechanism do they mutate? Most importantly, what governs the intricate balance between the frequent genesis and expansion of simple repetitive arrays, and the fact that microsatellite repeats rarely reach appreciable lengths? In other words, how do microsatellites evolve?
2,140 citations
TL;DR: WNT signalling has been studied primarily in developing embryos, but WNTs also have important functions in adults, and aberrant signalling by WNT pathways is linked to a range of diseases, most notably cancer.
Abstract: WNT signalling has been studied primarily in developing embryos, in which cells respond to WNTs in a context-dependent manner through changes in survival and proliferation, cell fate and movement. But WNTs also have important functions in adults, and aberrant signalling by WNT pathways is linked to a range of diseases, most notably cancer. What is the full range of diseases that involve WNT pathways? Can inhibition of WNT signalling form the basis of an effective therapy for some cancers? Could activation of WNT signalling provide new therapies for other clinical conditions? Finally, on the basis of recent experiments, might WNTs normally participate in self-renewal, proliferation or differentiation of stem cells? If so, altering WNT signalling might be beneficial to the use of stem cells for therapeutic means.
1,660 citations
TL;DR: It is proposed that the microRNA milieu, unique to each cell type, productively dampens the expression of thousands of mRNAs and provides important context for the evolution of all metazoan mRNA sequences.
Abstract: We propose that the microRNA milieu, unique to each cell type, productively dampens the expression of thousands of mRNAs and provides important context for the evolution of all metazoan mRNA sequences. For genes that should not be expressed in a particular cell type, protein output is lowered to inconsequential levels. For other genes, dosage is adjusted in a manner that allows for customized expression in different cell types while achieving a more uniform level within each cell type. In these ways, the microRNAs add an extensive layer of gene control that integrates with transcriptional and other regulatory processes to expand the complexity of metazoan gene expression.
1,430 citations
TL;DR: Genome sequences reveal that a deluge of DNA from organelle DNA has constantly been bombarding the nucleus since the origin of organelles, abolished organelle autonomy and increased nuclear complexity.
Abstract: Genome sequences reveal that a deluge of DNA from organelles has constantly been bombarding the nucleus since the origin of organelles. Recent experiments have shown that DNA is transferred from organelles to the nucleus at frequencies that were previously unimaginable. Endosymbiotic gene transfer is a ubiquitous, continuing and natural process that pervades nuclear DNA dynamics. This relentless influx of organelle DNA has abolished organelle autonomy and increased nuclear complexity.
1,324 citations
TL;DR: The purpose and mechanisms of the leading algorithms, with a particular emphasis on metazoan sequence analysis, are introduced and key issues that users should take into consideration in interpreting the results are identified.
Abstract: The compilation of multiple metazoan genome sequences and the deluge of large-scale expression data have combined to motivate the maturation of bioinformatics methods for the analysis of sequences that regulate gene transcription. Historically, these bioinformatics methods have been plagued by poor predictive specificity, but new bioinformatics algorithms that accelerate the identification of regulatory regions are drawing disgruntled users back to their keyboards. However, these new approaches and software are not without problems. Here, we introduce the purpose and mechanisms of the leading algorithms, with a particular emphasis on metazoan sequence analysis. We identify key issues that users should take into consideration in interpreting the results and provide an online training example to help researchers who wish to test online tools before taking an independent foray into the bioinformatics of transcription regulation.
1,217 citations
TL;DR: A gene map of the xMHC is presented and its content in relation to paralogy, polymorphism, immune function and disease is reviewed.
Abstract: The major histocompatibility complex (MHC) is the most important region in the vertebrate genome with respect to infection and autoimmunity, and is crucial in adaptive and innate immunity. Decades of biomedical research have revealed many MHC genes that are duplicated, polymorphic and associated with more diseases than any other region of the human genome. The recent completion of several large-scale studies offers the opportunity to assimilate the latest data into an integrated gene map of the extended human MHC. Here, we present this map and review its content in relation to paralogy, polymorphism, immune function and disease.
1,047 citations
TL;DR: The cost of DNA sequencing continues to fall, which makes it feasible to develop genomic resources for new model species that are well suited for studying questions in evolutionary biology.
Abstract: The cost of DNA sequencing continues to fall, which makes it feasible to develop genomic resources for new model species that are well suited for studying questions in evolutionary biology. The thousands of closely related cichlid fishes in the lakes of East Africa are an ideal model system for understanding the genetic basis of vertebrate speciation. Genomic techniques are helping to integrate empirical and theoretical studies by identifying the genes that underlie the phenotypic differences among species.
984 citations
TL;DR: It is argued that epistasis should be accounted for in complex trait studies; current study designs for detecting epistasis are critically assessed and how these might be adapted for use in additional populations, including humans.
Abstract: Interactions among loci or between genes and environmental factors make a substantial contribution to variation in complex traits such as disease susceptibility. Nonetheless, many studies that attempt to identify the genetic basis of complex traits ignore the possibility that loci interact. We argue that epistasis should be accounted for in complex trait studies; we critically assess current study designs for detecting epistasis and discuss how these might be adapted for use in additional populations, including humans.
TL;DR: The latest techniques promise to provide cheap, high-throughput methods for genotyping existing markers, but might other traditional approaches offer better value for some applications?
Abstract: In less than half a century, molecular markers have totally changed our view of nature, and in the process they have evolved themselves. However, all of the molecular methods developed over the years to detect variation do so in one of only three conceptually different classes of marker: protein variants (allozymes), DNA sequence polymorphism and DNA repeat variation. The latest techniques promise to provide cheap, high-throughput methods for genotyping existing markers, but might other traditional approaches offer better value for some applications?
TL;DR: Evidence that genes that have similar and/or coordinated expression are often clustered is reviewed and it is asked how such clusters evolve and how this relates to mechanisms that control gene expression.
Abstract: In eukaryotes, unlike in bacteria, gene order has typically been assumed to be random. However, the first statistically rigorous analyses of complete genomes, together with the availability of abundant gene-expression data, have forced a paradigm shift: in every complete eukaryotic genome that has been analysed so far, gene order is not random. It seems that genes that have similar and/or coordinated expression are often clustered. Here, we review this evidence and ask how such clusters evolve and how this relates to mechanisms that control gene expression.
TL;DR: Do non-coding RNAs that are derived from the introns and exons of protein- coding and non-protein-c coding genes represent a fundamental advance in the genetic operating system of higher organisms?
Abstract: Do non-coding RNAs that are derived from the introns and exons of protein-coding and non-protein-coding genes represent a fundamental advance in the genetic operating system of higher organisms? Recent evidence from comparative genomics and molecular genetics indicates that this might be the case. If so, there will be profound consequences for our understanding of the genetics of these organisms, and in particular how the trajectories of differentiation and development and the differences among individuals and species are genomically programmed. But how might this hypothesis be tested?
TL;DR: Various novel sequencing technologies are being developed, each aspiring to reduce costs to the point at which the genomes of individual humans could be sequenced as part of routine health care.
Abstract: Nearly three decades have passed since the invention of electrophoretic methods for DNA sequencing. The exponential growth in the cost-effectiveness of sequencing has been driven by automation and by numerous creative refinements of Sanger sequencing, rather than through the invention of entirely new methods. Various novel sequencing technologies are being developed, each aspiring to reduce costs to the point at which the genomes of individual humans could be sequenced as part of routine health care. Here, we review these technologies, and discuss the potential impact of such a 'personal genome project' on both the research community and on society.
TL;DR: Comparative genomics is beginning to identify the functional components of the chromosome and that in turn will set the stage for the functional characterization of the sequences.
Abstract: The sequence of chromosome 21 was a turning point for the understanding of Down syndrome. Comparative genomics is beginning to identify the functional components of the chromosome and that in turn will set the stage for the functional characterization of the sequences. Animal models combined with genome-wide analytical methods have proved indispensable for unravelling the mysteries of gene dosage imbalance.
TL;DR: The authors' ability to predict the spread of drug-resistance and immune-escape mutations depends on understanding how HIV evolution differs within and among hosts and on the role played by positive selection.
Abstract: Understanding the evolution of the human immunodeficiency virus (HIV) is crucial for reconstructing its origin, deciphering its interaction with the immune system and developing effective control strategies. Although it is clear that HIV-1 and HIV-2 originated in African primates, dating their transmission to humans is problematic, especially because of frequent recombination. Our ability to predict the spread of drug-resistance and immune-escape mutations depends on understanding how HIV evolution differs within and among hosts and on the role played by positive selection. For this purpose, extensive sampling of HIV genetic diversity is required, and is essential for informing the design of HIV vaccines.
TL;DR: An increasing amount of evidence indicates that genomic variants in both coding and non-coding sequences can have unexpected deleterious effects on the splicing of the gene transcript.
Abstract: When genome variants are identified in genomic DNA, especially during routine analysis of disease-associated genes, their functional implications might not be immediately evident. Distinguishing between a genomic variant that changes the phenotype and one that does not is a difficult task. An increasing amount of evidence indicates that genomic variants in both coding and non-coding sequences can have unexpected deleterious effects on the splicing of the gene transcript. So how can benign polymorphisms be distinguished from disease-associated splicing mutations?
TL;DR: Mouse models of several of these syndromes have indicated ways in which conditions could be treated and genes and developmental processes that underlie the many human disorders in which tooth development is defective are identified.
Abstract: A wealth of information has recently become available on the molecular signals that are required to form and pattern the dentition in the mouse, shedding light on how important decisions about tooth shape, tooth number and cusp (cone-shaped prominence) number are generated. This information, which has been gleaned principally from knockout mice and manipulation of organ cultures, has been used to identify the genes and developmental processes that underlie the many human disorders in which tooth development is defective. Mouse models of several of these syndromes have also indicated ways in which such conditions could be treated.
TL;DR: The plasticity of the 5′ splice sites of multicellular eukaryotes means that these sites can be used in both constitutive and alternative splicing, and for the regulation of the inclusion/skipping ratio in alternativesplicing.
Abstract: Alternative splicing creates transcriptome diversification, possibly leading to speciation. A large fraction of the protein-coding genes of multicellular organisms are alternatively spliced, although no regulated splicing has been detected in unicellular eukaryotes such as yeasts. A comparative analysis of unicellular and multicellular eukaryotic 5' splice sites has revealed important differences - the plasticity of the 5' splice sites of multicellular eukaryotes means that these sites can be used in both constitutive and alternative splicing, and for the regulation of the inclusion/skipping ratio in alternative splicing. So, alternative splicing might have originated as a result of relaxation of the 5' splice site recognition in organisms that originally could support only constitutive splicing.
TL;DR: For example, forensic DNA analysis is key to the conviction or exoneration of suspects and the identification of victims of crimes, accidents and disasters, driving the development of innovative methods in molecular genetics, statistics and the use of massive intelligence databases as mentioned in this paper.
Abstract: Sherlock Holmes said "it has long been an axiom of mine that the little things are infinitely the most important", but never imagined that such a little thing, the DNA molecule, could become perhaps the most powerful single tool in the multifaceted fight against crime. Twenty years after the development of DNA fingerprinting, forensic DNA analysis is key to the conviction or exoneration of suspects and the identification of victims of crimes, accidents and disasters, driving the development of innovative methods in molecular genetics, statistics and the use of massive intelligence databases.
TL;DR: This work considers how the effect size of the susceptibility locus, the frequency of the disease allele(s), the Frequency of the marker allele (s) that are correlated with the disease alleles and the extent of linkage disequilibrium together influence genetic association studies.
Abstract: Small effect sizes, common-disease/common-variant versus rare variant influences, biased single nucleotide polymorphism ascertainment and low linkage disequilibrium have recently been discussed as impediments to association studies. Such a focus on the individual factors that highlight their maximum potential effect (whether positive or deleterious) is often optimistic as, in practice, they do not operate in isolation. Instead, they work jointly to generate the disease gene architecture and to determine the ability of a study to discover it. Here, we consider how the effect size of the susceptibility locus, the frequency of the disease allele(s), the frequency of the marker allele(s) that are correlated with the disease allele(s) and the extent of linkage disequilibrium together influence genetic association studies.
TL;DR: The old and new players that are involved in the initial steps of testis and ovary development are reviewed.
Abstract: The pivotal point of vertebrate sex determination is the development of the gonad into a testis or ovary, which governs phenotypic sex through the production of hormones. The identification of Sry, the genetic switch that controls testis development in mammals, fuelled the race for the discovery of downstream pathways. Comparative analyses of XY versus XX gonadogenesis in both mouse and human genetic mutants have uncovered a burgeoning network of intra- and extra-cellular pathways. Here, we review the old and new players that are involved in the initial steps of testis and ovary development.
TL;DR: It is argued that cryptic genetic variation is pervasive but under-appreciated, recent progress in determining the nature and identity of genes that underlie cryptic genetic effects is highlighted, and future research directions are outlined.
Abstract: Cryptic genetic variation is the dark matter of biology: it is variation that is not normally seen, but that might be an essential source of physiological and evolutionary potential. It is uncovered by environmental or genetic perturbations, and is thought to modify the penetrance of common diseases, the response of livestock and crops to artificial selection and the capacity of populations to respond to the emergence of a potentially advantageous macro-mutation. We argue in this review that cryptic genetic variation is pervasive but under-appreciated, we highlight recent progress in determining the nature and identity of genes that underlie cryptic genetic effects and we outline future research directions.
TL;DR: When the genome sequences of domestic animals become available the identification of the mutations that underlie the transformation from a wild to a domestic species will be a realistic and important target.
Abstract: One of the 'grand challenges' in modern biology is to understand the genetic basis of phenotypic diversity within and among species. Thousands of years of selective breeding of domestic animals has created a diversity of phenotypes among breeds that is only matched by that observed among species in nature. Domestic animals therefore constitute a unique resource for understanding the genetic basis of phenotypic variation. When the genome sequences of domestic animals become available the identification of the mutations that underlie the transformation from a wild to a domestic species will be a realistic and important target.
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TL;DR: Molecular studies of a handful of genes that are involved in maintaining reproductive isolation between species have provided some striking insights, suggesting that despite being strongly influenced by positive selection, speciation genes are often non-essential, having functions that are only loosely coupled to reproductive isolation.
Abstract: It is only in the past five years that studies of speciation have truly entered the molecular era. Recent molecular analyses of a handful of genes that are involved in maintaining reproductive isolation between species (speciation genes) have provided some striking insights. In particular, it seems that despite being strongly influenced by positive selection, speciation genes are often non-essential, having functions that are only loosely coupled to reproductive isolation. Molecular studies might also resolve the long-running debate on the relative importance of allopatric and parapatric modes of speciation.
TL;DR: The underlying advantages of Bayesian approaches are putting them at the forefront of genetic data analysis in an increasing number of areas.
Abstract: Bayesian statistics allow scientists to easily incorporate prior knowledge into their data analysis. Nonetheless, the sheer amount of computational power that is required for Bayesian statistical analyses has previously limited their use in genetics. These computational constraints have now largely been overcome and the underlying advantages of Bayesian approaches are putting them at the forefront of genetic data analysis in an increasing number of areas.
TL;DR: Technical advances in areas such as high-throughput sequencing, microsatellite analysis and non-invasive DNA sampling have led to a much-expanded role for genetics in conservation, allowing for more precise conservation decisions to be made.
Abstract: The 'crisis discipline' of conservation biology has voraciously incorporated many technologies to speed up and increase the accuracy of conservation decision-making. Genetic approaches to characterizing endangered species or areas that contain endangered species are prime examples of this. Technical advances in areas such as high-throughput sequencing, microsatellite analysis and non-invasive DNA sampling have led to a much-expanded role for genetics in conservation. Such expansion will allow for more precise conservation decisions to be made and, more importantly, will allow conservation genetics to contribute to area- and landscape-based decision-making processes.
TL;DR: Knowing the gene variants that cause differences among patients has the potential to allow 'personalized' drug therapy and to avoid therapeutic failure and serious side effects.
Abstract: Physicians have long been aware of the subtle differences in the responses of patients to medication. The recognition that a part of this variation is inherited, and therefore predictable, created the field of pharmacogenetics fifty years ago. Knowing the gene variants that cause differences among patients has the potential to allow 'personalized' drug therapy and to avoid therapeutic failure and serious side effects.