We apply molecular code theory to a rule-based model of the human inner kinetochore and study how complex formation in general can give rise to molecular codes. We analyze 105 reaction networks generated from the rule-based inner kinetochore model in two variants: with and without dissociation of complexes. Interestingly, we found codes only when some but not all complexes are allowed to dissociate. We show that this is due to the fact that in the kinetochore model (...) proteins can only bind at kinetochores by attaching to already attached proteins and cannot form complexes in free solution. Using a generalized linear mixed model we study which centromere protein can take which role in a molecular code . By this, associations between CENPs and code roles are found. We observed that CenpA is a major risk factor while CenpQ is a major protection factor . Finally we show, using an abstract model of copolymer formation, that molecular codes can also be realized solely by the formation of stable complexes, which do not dissociate. For example, with particular dimers as context a molecular code mapping from two different monomers to two particular trimers can be realized just by non-selective complex formation. We conclude that the formation of protein complexes can be utilized by the cell to implement molecular codes. Living cells thus facilitate a subsystem allowing for an enormous flexibility in the realization of mappings, which can be used for specific regulatory processes, e.g. via the context of a mapping. (shrink)

Molecular codes can be considered a special type of mapping among molecular species in biochemical systems. The formalization of molecular codes allows to identify these in network models of real world systems. Analyzing algorithmically identified codes leads to the observation that codes does not necessarily stand alone, but that we can identify certain relations among codes. In this paper I will define two types of relations that can occur among codes, code (...) linkage and code nesting, and will discuss implications of this finding. (shrink)

The discoveries, advancements and continuing controversies in the field of molecular evolution are reviewed. Topics summarized are (1) the evolution of the genetic code, (2) gene evolution including the demonstration of homology, estimation of sequence divergence, phylogenetic trees, the molecular clock and the origin of genes and gene families by various genetic mechanisms, and (3) eukaryotic genome evolution, including the highly repeated satellite sequences, the interspersed and potentially mobile repeated sequences and the unique sequence fraction of the genome.

ArgumentThis paper examines the role of metaphors in science on the basis of a historical case study. The study explores how metaphors of “genetic information,” “genetic code,” and scripture representations of heredity entered molecular biology and reshaped experimentation during the 1950s and 1960s. Following the approach of the philosopher Hans Blumenberg, I will argue that metaphors are not merely a means of popularization or a specific kind of modeling but rather are representations that can unfold an operational force of (...) their own.While the influence of cybernetics and information theory on molecular biology is well documented in historical analysis throughout recent years, this paper offers new insights into the metaphysical and religious resonances of textual metaphors in the life sciences. The main focus will be on developments in Germany, in particular on the work of the German biochemist Gerhard Schramm. In this historical case study the interaction between metaphors and experimental practices will be discussed. The paper analyzes different phases in the use of metaphors during the 1950s and 1960s: it will explore how the metaphors of a “genetic alphabet” or of “genetic code” developed into a new research program and eventually attained ontological status in the early 1960s. At that time Schramm's use of textual metaphors was reminiscent of nineteenth-century German natural philosophy. In this case, the metaphorical shift shows how the metaphor of a “genetic text” or a “genetic code,” which were central for the emerging molecular biology, drew on older cultural traditions with all of their metaphysical and religious preoccupations. (shrink)

Kawasaki disease (KD) is an acute self‐limiting vasculitis with coronary complications, usually occurring in children. The incidence of KD in children is increasing year by year, mainly in East Asian countries, but relatively stably in Europe and America. Although studies on KD have been reported, the pathogenesis of KD is unknown. With the development of high‐throughput sequencing technology, growing number of regulatory noncoding RNAs (ncRNAs) including microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA) have been identified to involved (...) in KD. However, the role of ncRNAs in KD has not been comprehensively elucidated. Therefore, it is significative to study the regulatory role of ncRNA in KD, which might help to uncover new and effective therapeutic strategies for KD. In this review, we summarize recent studies on ncRNA in KD from the perspectives of immune disorders, inflammatory disorders, and endothelial dysfunction, and highlight the potential of ncRNAs as therapeutic targets for KD. (shrink)

Systems Biology and the Modern Synthesis are recent versions of two classical biological paradigms that are known as structuralism and functionalism, or internalism and externalism. According to functionalism (or externalism), living matter is a fundamentally passive entity that owes its organization to external forces (functions that shape organs) or to an external organizing agent (natural selection). Structuralism (or internalism), is the view that living matter is an intrinsically active entity that is capable of organizing itself from within, with purely internal (...) processes that are based on mathematical principles and physical laws. At the molecular level, the basic mechanism of the Modern Synthesis is molecular copying, the process that leads in the short run to heredity and in the long run to natural selection. The basic mechanism of Systems Biology, instead, is self-assembly, the process by which many supramolecular structures are formed by the spontaneous aggregation of their components. In addition to molecular copying and self-assembly, however, molecular biology has uncovered also a third great mechanism at the heart of life. The existence of the genetic code and of many other organic codes in Nature tells us that molecular coding is a biological reality and we need therefore a framework that accounts for it. This framework is Code biology, the study of the codes of life, a new field of research that brings to light an entirely new dimension of the living world and gives us a completely new understanding of the origin and the evolution of life. (shrink)

The paper argues against the central dogma and its interpretation by C. Kenneth Waters and Alex Rosenberg. I argue that certain phenomena in the regulation of gene expression provide a break with the central dogma, according to which sequence specificity for a gene product must be template derived. My thesis of 'molecular epigenesis' with its three classes of phenomena, sequence 'activation', 'selection', and 'creation', is exemplified by processes such as transcriptional activation, alternative cis- and trans-splicing, and RNA editing. It (...) argues that other molecular resources share the causal role of genes; the sequence specificity for the linear sequence of any gene product is distributed between the coding sequence, cis-acting sequences, trans-acting factors, environmental signals, and the contingent history of the cell (thesis of distributed causal specificity). I conclude that the central dogma has unnecessarily restricted genetic research to the sequencing of protein-coding genes, unilinear pathway analyses, and the focus on exclusive specificity. (shrink)

Biological psychiatry has been dominated by a psychopharmacologically-driven neurotransmitter dysfunction paradigm. The objective of this paper is to explore a reductionist assumption underlying this paradigm, and to suggest an improvement on it. The methods used are conceptual analysis with a comparative approach, particularly using illustrations from the history of both biological psychiatry and molecular biology. The results are that complete reduction to physicochemical explanations is not fruitful, at least in the initial stages of research in the medical and life (...) sciences, and that an appropriate (non-reducible) integrative principle - addressing a property of the whole system under study - is required for each domain of research. This is illustrated in Pauling's use of a topological integrative principle for the discovery of the functioning of proteins and in Watson and Crick's use of the notion of a genetic code as an integrative principle for the discovery of the structure of genes. The neurotransmitter dysfunction paradigm addresses single molecules and their neural pathways, yet their interactions within the CNS as a whole seem most pertinent to mental disorders such as schizophrenia. The lack within biological psychiatry of an integrative principle addressing a property of the CNS as a whole may be responsible for the empirical failure of orthomolecular psychiatry, as well as for the central role that serendipity has played in the study of mental disorders, which is dominated by the neurotransmitter paradigm. The conclusion is that research in biological psychiatry may benefit from using, at least initially, some integrative principle(s) addressing a property of the CNS as a whole, such as connectionism or a hierarchical notion. (shrink)

Thomas Kuhn described the progress of science as comprising occasional paradigm shifts separated by interludes of ‘normal science’. The paradigm that has held sway since the inception of molecular biology is that genes (mainly) encode proteins. In parallel, theoreticians posited that mutation is random, inferred that most of the genome in complex organisms is non‐functional, and asserted that somatic information is not communicated to the germline. However, many anomalies appeared, particularly in plants and animals: the strange genetic phenomena of (...) paramutation and transvection; introns; repetitive sequences; a complex epigenome; lack of scaling of (protein‐coding) genes and increase in ‘noncoding’ sequences with developmental complexity; genetic loci termed ‘enhancers’ that control spatiotemporal gene expression patterns during development; and a plethora of ‘intergenic’, overlapping, antisense and intronic transcripts. These observations suggest that the original conception of genetic information was deficient and that most genes in complex organisms specify regulatory RNAs, some of which convey intergenerational information. Also see the video abstract here: https://youtu.be/qxeGwahBANw. (shrink)

The importance of viruses as model organisms is well-established in molecular biology and Max Delbrück’s phage group set standards in the DNA phage field. In this paper, I argue that RNA phages, discovered in the 1960s, were also instrumental in the making of molecular biology. As part of experimental systems, RNA phages stood for messenger RNA, genes and genome. RNA was thought to mediate information transfers between DNA and proteins. Furthermore, RNA was more manageable at the bench than (...) DNA due to the availability of specific RNases, enzymes used as chemical tools to analyse RNA. Finally, RNA phages provided scientists with a pure source of mRNA to investigate the genetic code, genes and even a genome sequence. This paper focuses on Walter Fiers’ laboratory at Ghent University and their work on the RNA phage MS2. When setting up his Laboratory of Molecular Biology, Fiers planned a comprehensive study of the virus with a strong emphasis on the issue of structure. In his lab, RNA sequencing, now a little-known technique, evolved gradually from a means to solve the genetic code, to a tool for completing the first genome sequence. Thus, I follow the research pathway of Fiers and his ‘RNA phage lab’ with their evolving experimental system from 1960 to the late 1970s. This study illuminates two decisive shifts in post-war biology: the emergence of molecular biology as a discipline in the 1960s in Europe and of genomics in the 1990s. (shrink)

The extent of neurogenesis in Drosophila is under the control of the so‐called neurogenic genes, named for their mutant phenotype of causing neural hyperplasia. Their wild‐type products appear to be responsible for a signal chain that decides the fate of ectodermal cells in the embryo. Various kinds of data, from cell transplantation experiments as well as from genetic and molecular analyses, suggest that the proteins encoded by the genes Notch and Delta may act at the membrane of the signal‐transmitting (...) cells to provide a ligand to a still unknown receptor molecule; in contrast, the locus of Enhancer of split codes for several functions related to the transduction and further processing of the signal. (shrink)

Recently the terms “codes” and “information” as used in the context of molecular biology have been the subject of much discussion. Here I propose that a variety of structural realism can assist us in rethinking the concepts of DNA codes and information apart from semantic criteria. Using the genetic code as a theoretical backdrop, a necessary distinction is made between codes qua symbolic representations and information qua structure that accords with data. Structural attractors are also shown (...) to be entailed by the mapping relation that any DNA code is a part of (as the domain). In this framework, these attractors are higher-order informational structures that obviate any “DNA-centric” reductionism. In addition to the implications that are discussed, this approach validates the array of coding systems now recognized in molecular biology. (shrink)

In 1958, Francis Crick distinguished the flow of information from the flow of matter and the flow of energy in the mechanism of protein synthesis. Crick’s claims about information flow and coding in molecular biology are viewed from the perspective of a new characterization of mechanisms and from the perspective of information as holding a key to distinguishing work in molecular biology from that of biochemistry in the 1950s–1970s . Flow of matter from beginning to end does not (...) occur in the protein synthesis mechanism; flow of information does. The flow of information and coding in molecular biological mechanisms are distinguished, on the one hand, from formal information theory, and, on the other, from information as used in cognitive neuroscience, where information and representation are often coupled. (shrink)

Common themes are emerging in the molecular mechanisms of long non‐coding RNA‐mediated gene repression. Long non‐coding RNAs (lncRNAs) participate in targeted gene silencing through chromatin remodelling, nuclear reorganisation, formation of a silencing domain and precise control over the entry of genes into silent compartments. The similarities suggest that these are fundamental processes of transcription regulation governed by lncRNAs. These findings have paved the way for analogous investigations on other lncRNAs and chromatin remodelling enzymes. Here we discuss these common mechanisms (...) and provide our view on other molecules that warrant similar investigations. We also present our concepts on the possible mechanisms that may facilitate the exit of genes from the silencing domains and their potential therapeutic applications. Finally, we point to future areas of research and put forward our recommendations for improvements in resources and applications of existing technologies towards targeted outcomes in this active area of research. (shrink)

This article reconsiders the theoretical role of the genetic code. By drawing on published and unpublished sources from the 1950s, I analyse how the code metaphor was actually employed by the scientists who first promoted its use. The analysis shows that the term ‘code’ picked out mechanism sketches, consisting of more or less detailed descriptions of ordinary molecular components, processes, and structural properties of the mechanism of protein synthesis. The sketches provided how-possibly explanations for the ordering of amino acids (...) by nucleic acids. I argue that employing the code metaphor was justified in virtue of its descriptive-denotational and explanatory roles, and because it highlighted a similarity with conventional codes that was particularly salient at the time. 1 Introduction2 Coding Schemes in the 1950s2.1 The research problem: Determining amino acid sequences2.2 The solution: Mapping schemes or ‘codes’3 The Code Metaphor Played Descriptive and Explanatory Roles4 Theness of Codes and the Expendability of the Code Metaphor5 The Role of Arbitrariness6 Conclusions. (shrink)

Although the knowledge about biological systems has advanced exponentially in recent decades, it is surprising to realize that the very definition of Life keeps presenting theoretical challenges. Even if several lines of reasoning seek to identify the essence of life phenomenon, most of these thoughts contain fundamental problem in their basic conceptual structure. Most concepts fail to identify either necessary or sufficient features to define life. Here, we analyzed the main conceptual frameworks regarding theoretical aspects that have been supporting the (...) most accepted concepts of life, such as (i) the physical, (ii) the cellular and (iii) the molecular approaches. Based on an ontological analysis, we propose that Life should not be positioned under the ontological category of Matter. Yet, life should be better understood under the top-level ontology of “Process”. Exercising an epistemological approach, we propose that the essential characteristic that pervades each and every living being is the presence of organic codes. Therefore, we explore theories in biosemiotics and code biology in order to propose a clear concept of life as a macrocode composed by multiple inter-related coding layers. This way, as life is a sort of metaphysical process of encoding, the living beings became the molecular materialization of that process. From the proposed concept, we show that the evolutionary process is a fundamental characteristic for life’s maintenance but it is not necessary to define life, as many organisms are clearly alive but they do not participate in the evolutionary process (such as infertile hybrids). The current proposition opens a fertile field of debate in astrobiology, epistemology, biosemiotics, code biology and robotics. (shrink)

Animals use their chemosensory systems to detect and discriminate among chemical cues in the environment. Remarkable progress has recently been made in our knowledge of the molecular and cellular basis of chemosensory perception in insects, based largely on studies in Drosophila. This progress has been possible due to the identification of gene families for olfactory and gustatory receptors, the use of electro‐physiological recording techniques on sensory neurons, the multitude of genetic manipulations that are available in this species, and insights (...) from several insect model systems. Recent studies show that the superfamily of chemoreceptor proteins represent the essential elements in chemosensory coding, endowing chemosensory neurons with their abilities to respond to specific sets of odorants, tastants or pheromones. Investigating how insects detect chemicals in their environment can show us how receptor protein structures relate to ligand binding, how nervous systems process complex information, and how chemosensory systems and genes evolve. BioEssays 28:23–34, 2006. © 2005 Wiley Periodicals, Inc. (shrink)

Background There are intense discussions about the ethical and societal implications of biomedical engineering, but little data to suggest how scientists think about the ethics of their work. The aim of this study is to describe how scientists frame the ethics of their research, with a focus on the field of molecular systems engineering.Methods Semi-structured qualitative interviews were conducted during 2021–2022, as part of a larger study. This analysis includes a broad question about how participants view ethics as related (...) to their work, with follow up probes about the topics they consider most important. Interviews were transcribed, inductively coded by two researchers to consensus, and analyzed thematically.Results Twenty-four scientists participated in the study. Interviewees hold positions as professors, principal investigators, and senior staff researchers in universities or research institutes in the United States and Europe. Among those scientists who reported reflecting on ethical considerations in their work, many equated ethics with research ethics topics (e.g., safety, replicability), or with regulation and guidelines. Participants expressed the view that ethical issues are primarily relevant for clinical trials of bioengineered products, or for those working with animal or human subjects. Scientists described their research as “too early” or “not examining anything living” with regard to ethical reflection. Finally, many felt that ethics is seen as territory for experts and therefore beyond scientists’ competencies.Conclusions Molecular systems engineering scientists currently focus on regulatory aspects as the framework for their ethical analyses. They describe using a framework to define when life arises, as a means to determine when further ethical engagement is warranted. Further research is needed to investigate how scientists relate to the ethics of their scientific work, and build consensus around concepts of life, autonomous behavior, and physiological relevance of bioengineered systems. (shrink)

Historians of molecular biology have paid significant attention to the role of scientific instruments and their relationship to the production of biological knowledge. For instance, Lily Kay has examined the history of electrophoresis, Boelie Elzen has analyzed the development of the ultracentrifuge as an enabling technology for molecular biology, and Nicolas Rasmussen has examined how molecular biology was transformed by the introduction of the electron microscope (Kay 1998, 1993; Elzen 1986; Rasmussen 1997). 1 Collectively, these historians have (...) demonstrated how instruments and other elements of the material culture of the laboratory have played a decisive role in determining the kind and quantity of .. (shrink)

In recent years, sequencing technologies have enabled the identification of a wide range of non-coding RNAs (ncRNAs). Unfortunately, annotation and integration of ncRNA data has lagged behind their identification. Given the large quantity of information being obtained in this area, there emerges an urgent need to integrate what is being discovered by a broad range of relevant communities. To this end, the Non-Coding RNA Ontology (NCRO) is being developed to provide a systematically structured and precisely defined controlled vocabulary for the (...) domain of ncRNAs, thereby facilitating the discovery, curation, analysis, exchange, and reasoning of data about structures of ncRNAs, their molecular and cellular functions, and their impacts upon phenotypes. The goal of NCRO is to serve as a common resource for annotations of diverse research in a way that will significantly enhance integrative and comparative analysis of the myriad resources currently housed in disparate sources. It is our belief that the NCRO ontology can perform an important role in the comprehensive unification of ncRNA biology and, indeed, fill a critical gap in both the Open Biological and Biomedical Ontologies (OBO) Library and the National Center for Biomedical Ontology (NCBO) BioPortal. Our initial focus is on the ontological representation of small regulatory ncRNAs, which we see as the first step in providing a resource for the annotation of data about all forms of ncRNAs. The NCRO ontology is free and open to all users. (shrink)

The human genome project's lasting legacies are the emerging insights into human physiology and disease, and the ascendance of biology as the dominant science of the 21st century. Sequencing revealed that >90% of the human genome is not coding for proteins, as originally thought, but rather is overwhelmingly transcribed into non‐protein coding, or non‐coding, RNAs (ncRNAs). This discovery initially led to the hypothesis that most genomic DNA is “junk”, a term still championed by some geneticists and evolutionary biologists. In contrast, (...) molecular biologists and biochemists studying the vast number of transcripts produced from most of this genome “junk” often surmise that these ncRNAs have biological significance. What gives? This essay contrasts the two opposing, extant viewpoints, aiming to explain their bases, which arise from distinct reference frames of the underlying scientific disciplines. Finally, it aims to reconcile these divergent mindsets in hopes of stimulating synergy between scientific fields. (shrink)

Understanding the functional mechanisms underlying genetic signals associated with complex traits and common diseases, such as cancer, diabetes and Alzheimer's disease, is a formidable challenge. Many genetic signals discovered through genome‐wide association studies map to non‐protein coding sequences, where their molecular consequences are difficult to evaluate. This article summarizes concepts for the systematic interpretation of non‐coding genetic signals using genome annotation data sets in different cellular systems. We outline strategies for the global analysis of multiple association intervals and the (...) in‐depth molecular investigation of individual intervals. We highlight experimental techniques to validate candidate (potential causal) regulatory variants, with a focus on novel genome‐editing techniques including CRISPR/Cas9. These approaches are also applicable to low‐frequency and rare variants, which have become increasingly important in genomic studies of complex traits and diseases. There is a pressing need to translate genetic signals into biological mechanisms, leading to prognostic, diagnostic and therapeutic advances. (shrink)

The article reconciles contentious issues between code biology and biosemiotics. The framework of semantic biology and molecular meaning woven around organic codes by Marcello Barbieri defied classical informational conceptualizations of meaning in the biological realm while the discourse on meaning and agency and their respective (in)dependency on interpretation continues. Whereas the role of codes in agency is often secondary to other aspects, I present here a more consistent picture– integrating codes and artifacts to smoothly transcend from (...) the world of mechanistic molecular meaning to organismic agency. Interpretation is presented as a call-to-action based on intraindividual states, and sense-making as call-to-change based on interindividual communication. (shrink)

The genetic code is a set of instructions that determine how the information in our genetic material is translated into amino acids. In general, it is universal for all organisms, from viruses and bacteria to humans. However, in the last few decades, exceptions to this rule have been identified both in pro‐ and eukaryotes. In this review, we discuss the 16 described alternative eukaryotic nuclear genetic codes and observe theories of their appearance in evolution. We consider possible molecular (...) mechanisms that allow codon reassignment. Most reassignments in nuclear genetic codes are observed for stop codons. Moreover, in several organisms, stop codons can simultaneously encode amino acids and serve as termination signals. In this case, the meaning of the codon is determined by the additional factors besides the triplets. A comprehensive review of various non‐standard coding events in the nuclear genomes provides a new insight into the translation mechanism in eukaryotes. (shrink)

In eukaryotes, the messenger RNA (mRNA), the blueprint of a protein‐coding gene, is processed and packaged into a messenger ribonucleoprotein particle (mRNP) by mRNA‐binding proteins in the nucleus. The steps of mRNP formation – transcription, processing, packaging, and the orchestrated release of the export‐competent mRNP from the site of transcription for nuclear mRNA export – are tightly coupled to ensure a highly efficient and regulated process. The importance of highly accurate nuclear mRNP formation is illustrated by the fact that mutations (...) in components of this pathway lead to cellular inviability or to severe diseases in metazoans. We hypothesize that efficient mRNP formation is realized by a molecular mRNP packaging station, which is built by several recruitment platforms and coordinates the individual steps of mRNP formation. (shrink)

In his [1], David Berlinski explores, among other things, both what could be called a “sophisticated” and a “basic” analogy between languages and the genetic code. The basic analogy stems from the observation that the relationship between English and “Morse” appears to be formally similar to the relationship between DNA and protein. That is, just as sentences of the English language can be encoded into Morse, sequences of bases within strands of DNA are “transcribed” into polypeptides. To some, this “basic” (...) analogy. (shrink)

In light of scientific advances such as genomics, predictive diagnostics, genetically engineered agriculture, nuclear transfer cloning, and the manipulation of stem cells, the idea that genes carry predetermined molecular programs or blueprints is pervasive. Yet new scientific discoveries—such as rna transcripts of single genes that can lead to the production of different compounds from the same pieces of dna—challenge the concept of the gene alone as the dominant factor in biological development. Increasingly aware of the tension between certain empirical (...) results and interpretations of those results based on the orthodox view of genetic determinism, a growing number of scientists urge a rethinking of what a gene is and how it works. In this collection, a group of internationally renowned scientists present some prominent alternative approaches to understanding the role of dna in the construction and function of biological organisms. Contributors discuss alternatives to the programmatic view of dna, including the developmental systems approach, methodical culturalism, the molecular process concept of the gene, the hermeneutic theory of description, and process structuralist biology. None of the approaches cast doubt on the notion that dna is tremendously important to biological life on earth; rather, contributors examine different ideas of how dna should be represented, evaluated, and explained. Just as ideas about genetic codes have reached far beyond the realm of science, the reconceptualizations of genetic theory in this volume have broad implications for ethics, philosophy, and the social sciences. Contributors. Thomas Bürglin, Brian C. Goodwin, James Griesemer, Paul Griffiths, Jesper Hoffmeyer, Evelyn Fox Keller, Gerd B. Müller, Eva M. Neumann-Held, Stuart A. Newman, Susan Oyama, Christoph Rehmann-Sutter, Sahotra Sarkar, Jackie Leach Scully, Gerry Webster, Ulrich Wolf. (shrink)

How to interpret the “molecular gene” concept is discussed in this paper. I argue that the architecture of biological systems is hierarchical and multi-layered, exhibiting striking similarities to that of modern computers. Multiple layers exist between the genotype and system level property, the phenotype. This architectural complexity gives rise to the intrinsic complexity of the genotype-phenotype relationships. The notion of a gene being for a phenotypic trait or traits lacks adequate consideration of this complexity and has limitations in explaining (...) the genotype-phenotype relationships. I explore ways toward an integrative interpretation of the gene in the context of multi-layered biological systems. A gene, I argue, should be interpreted as a functional unit that is responsible for the trans-generation passage of the capacity to dynamically produce a biochemical activity or biochemical activities. At the molecular level, a gene is a genetic unit, a stretch of DNA sequence, which dictates the behavior and the dynamic production of the encoded cellular component(s). Embedded in a gene’s quadruple DNA code are the regulatory signals, such as those for RNA splicing and/or editing, as well as for transcription factor binding. A regulatory signal can be recognized by the gene expression machinery in one state, but not in another. The confusion caused by RNA splicing, editing, and a gene’s selective tissue distribution pattern is addressed. Instead of a context-dependent definition of the gene, I argue for the view that it is the same gene displaying multiple meanings, subject to differential interpretation by the cellular machinery in different states. In other words, the same gene gives rise to different products and expression levels under different conditions. (shrink)

The ArgumentThis paper focuses on the opening of a discursive space: the emergence of informational and scriptural representations of life and their self-negating consequences for the construction of biological meaning. It probes the notion of writing and the book of life and shows how molecular biology's claims to a status of language and texuality undermines its own objective of control. These textual significations were historically contingent. The informational representations of heredity and life were not an outcome of the internal (...) cognitive momentum of molecular biology; they were not a logical necessity of the unravelling of the base-pairing of the DNA double-helix. They were transported into molecular biology still within the protein paradigm of the gene in the 1940s and permeated nearly every discipline in the life and social sciences. These information-based models, metaphors, linguistic, and semiotic tools which were central to the formulation of the genetic code were transported into molecular biology from cybernetics, information theory, electronic computing, and control and communication systems — technosciences that were deeply embedded with the military experiences of world war II and the Cold War. The information discourse thus became fixed in molecular biology not because it worked in the narrow epistemic sense (it did not), but because it positioned molecular biology within postwar discourse and culture, perhaps within the transition to a post-modern information-based society. (shrink)

Barbieri introduced and developed the concept of organic codes. The most basic of them is the genetic code, a set of correspondence rules between otherwise unrelated sequences: strings of nucleotides on the one hand, polypeptidic chains on the other hand. Barbieri noticed that it implies ‘coding by convention’ as arbitrary as the semantic relations a language establishes between words and outer objects. Moreover, the major transitions in life evolution originated in new organic codes similarly involving conventional rules. Independently, (...) dealing with heredity as communication over time and relying on information theory, we asserted that the conservation of genomes over the ages demands that error-correcting codes make them resilient to casual errors. Moreover, the better conservation of very old parts of the genome demands that they result from combining successively established nested codes such that the older an information, the more numerous component codes protect it. Barbieri’s concept of organic code and that of genomic error-correcting code may seem unrelated. We show however that organic codes actually entail error-correcting properties. Error-correcting, in general, results from constraints being imposed on a set of sequences. Mathematical equalities are conveniently used in communication engineering for expressing constraints but error correction only needs that constraints exist. Biological sequences are similarly endowed with error-correcting ability by physical-chemical or linguistic constraints, thus defining ‘soft codes’. These constraints are moreover presumably efficient for correcting errors. Insofar as biological sequences are subjected to constraints, organic codes necessarily involve soft codes, and their successive onset results in the nested structure we hypothesized. Organic codes are generated and maintained by means of molecular ‘semantic feedback loops’. Each of these loops involves genes which code for proteins, the enzymatic action of which controls a function needed for the protein assembly. Taken together, thus, they control the assembly of their own structure as instructed by the genome and, once closed, these loops ensure their own conservation. However, the semantic feedback loops do not prevent the genome lengthening. It increases both the redundancy of the genome and the information quantity it bears, thus improving the genome reliability and the specificity of the enzymes, which enables further evolution. (shrink)

Glucocorticoid hormones are effective in controlling inflammation, but the mechanisms that confer this action are largely unknown. Recent advances in this field have shown that both positive and negative regulation of gene expression are necessary for this process. The genes whose activity are modulated in the anti‐inflammatory process code for several cytokines, adhesion molecules and enzymes. Most of them do not carry a classical binding site for regulation by a glucocorticoid receptor, but have instead regulatory sequences for transcription factors such (...) as AP‐1 or NF‐κ. This makes them unusual targets for glucocorticoid action and emphasizes the need for novel regulatory mechanisms. Recent studies describe an important contribution by protein‐protein interactions, in which several domains of the receptor participate; these studies provide a better understanding of the action of the receptor and offer opportunities for the design of steroidal compounds that could function more effectively as anti‐inflammatory drugs. (shrink)

We discuss the role of linguistic metaphors as a cognitive frame for the understanding of genetic information processing. The essential similarity between language and genetic information processing has been recognized since the very beginning, and many prominent scholars have noted the possibility of considering genes and genomes as texts or languages. Most of the core terms in molecular biology are based on linguistic metaphors. The processing of genetic information is understood as some operations on text – writing, reading and (...) editing and their specification (encoding/decoding, proofreading, transcription, translation, reading frame). The concept of gene reading can be traced from the archaic idea of the equation of Life and Nature with the Book. Thus, the genetics itself can be metaphorically represented as some operations on text (deciphering, understanding, codebreaking, transcribing, editing, etc.), which are performed by scientists. At the same time linguistic metaphors portrayed gene entities also as having the ability of reading. In the case of such “bio-reading” some essential features similar to the processes of human reading can be revealed: this is an ability to identify the biochemical sequences based on their function in an abstract system and distinguish between type and its contextual tokens of the same type. Metaphors seem to be an effective instrument for representation, as they make possible a two-dimensional description: biochemical by its experimental empirical results and textual based on the cognitive models of comprehension. In addition to their heuristic value, linguistic metaphors are based on the essential characteristics of genetic information derived from its dual nature: biochemical by its substance, textual (or quasi-textual) by its formal organization. It can be concluded that linguistic metaphors denoting biochemical objects and processes seem to be a method of description and explanation of these heterogeneous properties. (shrink)

There are two intriguing paradoxes in molecular biology-the inconsistent relationship between organismal complexity and (1) cellular DNA content and (2) the number of protein-coding genes-referred to as the C-value and G-value paradoxes, respectively. The C-value paradox may be largely explained by varying ploidy. The G-value paradox is more problematic, as the extent of protein coding sequence remains relatively static over a wide range of developmental complexity. We show by analysis of sequenced genomes that the relative amount of non-protein-coding sequence (...) increases consistently with complexity. We also show that the distribution of introns in complex organisms is non-random. Genes composed of large amounts of intronic sequence are significantly overrepresented amongst genes that are highly expressed in the nervous system, and amongst genes downregulated in embryonic stem cells and cancers. We suggest that the informational paradox in complex organisms may be explained by the expansion of cis-acting regulatory elements and genes specifying trans-acting non-protein-coding RNAs. (shrink)

Natural selection of specific protobiomonomers during abiogenic development of the prototype genetic code is hindered by the diversity of structural, spatial, and rotational isomers that have identical elemental composition and molecular mass (M), but can vary significantly in their physicochemical characteristics, such as the melting temperature Tm, the Tm:M ratio, and the solubility in water, due to different positions of atoms in the molecule. These parameters differ between cis- and trans-isomers of dicarboxylic acids, spatial monosaccharide isomers, and structural isomers (...) of α-, β-, and γ-amino acids. The stable planar heterocyclic molecules of the major nucleobases comprise four (C, H, N, O) or three (C, H, N) elements and contain a single –C=C bond and two nitrogen atoms in each heterocycle involved in C–N and C=N bonds. They exist as isomeric resonance hybrids of single and double bonds and as a mixture of tautomer forms due to the presence of –C=O and/or –NH2 side groups. They are thermostable, insoluble in water, and exhibit solid-state stability, which is of central importance for DNA molecules as carriers of genetic information. In M–Tm diagrams, proteinogenic amino acids and the corresponding codons are distributed fairly regularly relative to the distinct clusters of purine and pyrimidine bases, reflecting the correspondence between codons and amino acids that was established in different periods of genetic code development. The body of data on the evolution of the genetic code system indicates that the elemental composition and molecular structure of protobiomonomers, and their M, Tm, photostability, and aqueous solubility determined their selection in the emergence of the standard genetic code. (shrink)

We discuss the role of linguistic metaphors as a cognitive frame for the understanding of genetic information processing. The essential similarity between language and genetic information processing has been recognized since the very beginning, and many prominent scholars have noted the possibility of considering genes and genomes as texts or languages. Most of the core terms in molecular biology are based on linguistic metaphors. The processing of genetic information is understood as some operations on text – writing, reading and (...) editing and their specification (encoding/decoding, proofreading, transcription, translation, reading frame). The concept of gene reading can be traced from the archaic idea of the equation of Life and Nature with the Book. Thus, the genetics itself can be metaphorically represented as some operations on text (deciphering, understanding, code-breaking, transcribing, editing, etc.), which are performed by scientists. At the same time linguistic metaphors portrayed gene entities also as having the ability of reading. In the case of such “bio-reading” some essential features similar to the processes of human reading can be revealed: this is an ability to identify the biochemical sequences based on their function in an abstract system and distinguish between type and its contextual tokens of the same type. Metaphors seem to be an effective instrument for representation, as they make possible a two-dimensional description: biochemical by its experimental empirical results and textual based on the cognitive models of comprehension. In addition to their heuristic value, linguistic metaphors are based on the essential characteristics of genetic information derived from its dual nature: biochemical by its substance, textual (or quasi-textual) by its formal organization. It can be concluded that linguistic metaphors denoting biochemical objects and processes seem to be a method of description and explanation of these heterogeneous properties. (shrink)

Genomic function is dictated by a combination of DNA sequence and the molecular mechanisms controlling access to genetic information. Access to DNA can be determined by the interpretation of covalent modifications that influence the packaging of DNA into chromatin, including DNA methylation and histone modifications. These modifications are believed to be forms of “epigenetic codes” that exist in discernable combinations that reflect cellular phenotype. Although DNA methylation is known to play important roles in gene regulation and genomic function, (...) its contribution to the encoding of epigenetic information is just beginning to emerge. Here we discuss paradigms associated with the various components of DNA methylation/demethylation and recent advances in the understanding of its dynamic regulation in the genome, integrating these mechanisms into a framework to explain how DNA methylation could contribute to epigenetic codes. (shrink)

We formulate the following hypothesis: Life's origin may have occurred during the lower Archaean at a time when the environmental temperature was higher than it is at present. Preliminary consequences of this hypothesis are studied from the point of view of molecular evolution. We restrict our attention to implications regarding the genetic code. We conclude that alternative assignment of termination codons may be understood in terms of: (a) the elevated temperatures to which the progenote may initially have been exposed; (...) and (b) the subsequent response of its genome to the opportunity provided by the eventual loss of hyperthermal genetic expression during a thermal transition (TT) period, which was triggered off by the evolution of the dynamic Earth. (shrink)

The central dogma of biology holds that genetic information normally flows from DNA to RNA to protein. As a consequence it has been generally assumed that genes generally code for proteins, and that proteins fulfil not only most structural and catalytic but also most regulatory functions, in all cells, from microbes to mammals. However, the latter may not be the case in complex organisms. A number of startling observations about the extent of non-protein-coding RNA (ncRNA) transcription in the higher eukaryotes (...) and the range of genetic and epigenetic phenomena that are RNA-directed suggests that the traditional view of the structure of genetic regulatory systems in animals and plants may be incorrect. ncRNA dominates the genomic output of the higher organisms and has been shown to control chromosome architecture, mRNA turnover and the developmental timing of protein expression, and may also regulate transcription and alternative splicing. This paper re-examines the available evidence and suggests a new framework for considering and understanding the genomic programming of biological complexity, autopoletic development and phenotypic variation. BioEssays 25:930-939,2003. (C) 2003 Wiley Periodicals, Inc. (shrink)

Certain correspondences appear between the classifications and between the classes of various entities at molecular genetic level: types of fundamental correspondences between classifications and between classes of normal entities, on the one hand, and of mutant entities on the other hand; ranks of correspondences between classifications and between classes of entities. The concept of universality of the genetic code was reformulated on the basis of the above correspondences.

We discuss the role of linguistic metaphors as a cognitive frame for the understanding of genetic information processing. The essential similarity between language and genetic information processing has been recognized since the very beginning, and many prominent scholars have noted the possibility of considering genes and genomes as texts or languages. Most of the core terms in molecular biology are based on linguistic metaphors. The processing of genetic information is understood as some operations on text – writing, reading and (...) editing and their specification (encoding/decoding, proofreading, transcription, translation, reading frame). The concept of gene reading can be traced from the archaic idea of the equation of Life and Nature with the Book. Thus, the genetics itself can be metaphorically represented as some operations on text (deciphering, understanding, codebreaking, transcribing, editing, etc.), which are performed by scientists. At the same time linguistic metaphors portrayed gene entities also as having the ability of reading. In the case of such “bio-reading” some essential features similar to the processes of human reading can be revealed: this is an ability to identify the biochemical sequences based on their function in an abstract system and distinguish between type and its contextual tokens of the same type. Metaphors seem to be an effective instrument for representation, as they make possible a two-dimensional description: biochemical by its experimental empirical results and textual according to the cognitive models of comprehension. In addition to their heuristic value, linguistic metaphors are based on the essential characteristics of genetic information derived from its dual nature: biochemical by its substance, textual (or quasitextual) by its formal organization. It can be concluded that linguistic metaphors denoting biochemical objects and processes seem to be a method of description and explanation of these heterogeneous properties. (shrink)

RNA binding proteins (RBPs) are key factors for the regulation of gene expression by binding to cis elements, i.e. short sequence motifs in RNAs. Recent studies demonstrate that cooperative binding of multiple RBPs is important for the sequence‐specific recognition of RNA and thereby enables the regulation of diverse biological activities by a limited set of RBPs. Cross‐linking immuno‐precipitation (CLIP) and other recently developed high‐throughput methods provide comprehensive, genome‐wide maps of protein‐RNA interactions in the cell. Structural biology gives detailed insights into (...) molecular mechanisms and principles of RNA recognition by RBPs, but has so far focused on single RNA binding proteins and often on single RNA binding domains. The combination of high‐throughput methods and detailed structural biology studies is expected to greatly advance our understanding of the code for protein‐RNA recognition in gene regulation, as we review in this article. (shrink)

All sciences have epistemic assumptions, a language for expressing their theories or models, and symbols that reference observables that can be measured. In most sciences the language in which their models are expressed are not the focus of their attention, although the choice of language is often crucial for the model. On the contrary, biosemiotics, by definition, cannot escape focusing on the symbol–matter relationship. Symbol systems first controlled material construction at the origin of life. At this molecular level it (...) is only in the context of open-ended evolvability that symbol–matter systems and their functions can be objectively defined. Symbols are energy-degenerate structures not determined by laws that act locally as special boundary conditions or constraints on law-based energy-dependent matter in living systems. While this partial description holds for all symbol systems, cultural languages are much too complex to be adequately described only at the molecular level. Genetic language and cultural languages have common basic requirements, but there are many significant differences in their structures and functions. (shrink)

The recent finding that the human version of a neurodevelopmental enhancer of the Wnt receptor Frizzled 8 (FZD8) gene alters neural progenitor cell cycle timing and brain size is a step forward to understanding human brain evolution. The human brain is distinctive in terms of its cognitive abilities as well as its susceptibility to neurological disease. Identifying which of the millions of genomic changes that occurred during human evolution led to these and other uniquely human traits is extremely challenging. Recent (...) studies have demonstrated that many of the fastest evolving regions of the human genome function as gene regulatory enhancers during embryonic development and that the human‐specific mutations in them might alter expression patterns. However, elucidating molecular and cellular effects of sequence or expression pattern changes is a major obstacle to discovering the genetic bases of the evolution of our species. There is much work to do before human‐specific genetic and genomic changes are linked to complex human traits. (shrink)

This chapter contains sections titled: * Body Matters * Direction * Genetic Testing * Conclusion * References * Further Reading.

Analyses of environmental DNAs have provided tantalizing evidence for “rozellida” or “cryptomycota”, a clade of mostly undescribed and deeply diverging aquatic fungi. Here, we put cryptomycota into perspective through consideration of Rozella, the only clade member growing in culture. This is timely on account of the publication in Nature of the first images of uncultured cryptomycota from environmental filtrates, where molecular probes revealed non‐motile cyst‐like structures and motile spores, all lacking typical fungal chitinous cell walls. Current studies of Rozella (...) can complement these fragmentary observations from environmental samples. Rozella has a fungal‐specific chitin synthase and its resting sporangia have walls that appear to contain chitin. Cryptomycota, including Rozella, lack a cell wall when absorbing food but like some other fungi, they may have lost their “dinner jacket” through convergence. Rather than evolutionary intermediates, the cryptomycota may be strange, divergent fungi that evolved from an ancestor with a nearly complete suite of classical fungal‐specific characters. (shrink)

Homoeotic mutations alter the pattern of development by causing one body part to develop as some other. Among the genes identified by homoeotic mutations in Drosophila are some whose products appear to control development. A number of these have now been shown to share a common protein coding domain, which carries a sequence motif characteristic of DNA binding proteins. This protein coding domain is highly conserved in a wide range of animal taxa, including vertebrates.

Minimal genetic pre-formationism is defended, in that primacy is ascribed to DNA in the structuring of molecules through molecular codes. This together with the importance of such codes for stability and variation in living systems makes DNA categorically different from other causal factors. It is argued that post-transcriptional and post-translational processing in protein synthesis does not rob DNA of this structuring role. Notions of structuring causal powers that may vary in degree, of arbitrary molecular codes (...) that are more or less realized, of partial templating and of genetic information as a subspecies of mechanistic information are brought in to support this and to rival causal and semantic notions of information. It is concluded that the primacy of genes in their structuring of molecules goes together with parity between genes and non-genetic causal factors in regulation of living systems. This is seen to hold independently of the radical reconceptualization of organism cum environment that has been suggested in developmental systems theory. (shrink)

Semiotic inquiry relating the natural sciences to an evolutionary philosophy of nature must address the relations between physical, biological and psychic systems. This can be done in various ways that either emphasize substantial differences between extensional and intensional descriptions, or strive to bridge the gap between theories of mind and matter be means of semiotic notions. Biosemiotics can contribute to integrate our concepts of matter, energy and sign systems such as the notion of a basic molecular code, which is (...) not merely a chemical notion. It is argued that a semiotics of biological systems is in harmony with a pluralist ontology of emergent levels of organization. --- Published in: Edwina Taborsky, ed. (1999): Semiosis. Evolution. Energy: Towards a Reconceptualization of the Sign. Shaker Verlag, Aachen. (pp. 89-108). The book is based on the meeting "Semiosis. Evolution. Energy, Third International Conference on Semiotics", Victoria Colledge, University of Toronto, Canada, October 17-19, 1997. (shrink)

Collecting, comparing, and computing molecular sequences are among the most prevalent practices in contemporary biological research. They represent a specific way of producing knowledge. This paper explores the historical development of these practices, focusing on the work of Margaret O. Dayhoff, Richard V. Eck, and Robert S. Ledley, who produced the first computer-based collection of protein sequences, published in book format in 1965 as the Atlas of Protein Sequence and Structure. While these practices are generally associated with the rise (...) of molecular evolution in the 1960s, this paper shows that they grew out of research agendas from the previous decade, including the biochemical investigation of the relations between the structures and function of proteins and the theoretical attempt to decipher the genetic code. It also shows how computers became essential for the handling and analysis of sequence data. Finally, this paper reflects on the relationships between experimenting and collecting as two distinct “ways of knowing” that were essential for the transformation of the life sciences in the twentieth century. (shrink)