A explicação bioquímica da dominância permite a reinterpretação do fenômeno e da relação entre a genética da transmissão e a genética molecular. O objetivo deste trabalho é discutir sobre as explicações de dominância e recessividade a partir da proposta de Mendel, e como a genética molecular contemporânea contribuiu nesse sentido. Para tanto, considerar-se-á alguns autores que, no século XX, procuraram explicar o fenômeno bem como aspectos referentes à articulação entre genética da transmissão e (...) class='Hi'>genética molecular na interpretação da dominância. O artigo tratará de explicações para a dominância em dois níveis, o fenotípico (original de Mendel) e o molecular, visando mostrar que, sob o enfoque epistemológico, elas não tratam do mesmo fenômeno, isto é, são conhecimentos distintos e que historicamente se mesclaram. (shrink)

The Post-genomic Era includes features both from a methodological and epistemic point of view and from an ontological perspective. Firstly, it incorporates new methods of high-throughput sequencing of DNA and RNA, and the development of complete genomes that allow a precise reference of the molecular results obtained. In addition, from an ontological perspective, the centre of gravity of the molecular processes is placed on the expression of genes, and the way in which such expression is regulated; these features (...) turn the attention towards the study of Gene Regulatory Networks, and in particular to the role of RNA. This new molecular-biological perspective based on new methodologies and approaches is affecting the existing Molecular Genetics Theory including the definition of gen and Central Dogma of Molecular Biology. An important philosophical challenges posed by this new situation is the question whether there is a sophistication of the present theory or a New Theory of Molecular Genetics and whether there is an incommensurability between this theory and the accepted theory. In this work we evaluate these changes in the light of Kuhn’s theory of scientific revolution in order to propose an alternative between a moderate and a strong view. According to the moderate one, the Post-genomic changes do not properly involve a paradigm shift or, if they do, they constitute a minor revolution. The strong view considers that, the anomalies disclosed in the Molecular Genetics Theory at conceptual and methodological level and the Post-genomic changes they lead to suppose a scientific paradigm shift. (shrink)

El surgimiento de la biología molecular en la frontera que separa la teoría genética y la bioquímica constituye un buen banco de pruebas para distintas estrategias metacientíficas. El teoreticismo de las revoluciones científicas de Thomas S. Kuhn propende hacia un constructivismo social que no sirve para dar cuenta de la posible verdad y corrección del teorema de la doble hélice. El enfoque semántico (desarrollado por J. Sneed, W. Stegmüller, U Moulines, etc.), aunque pretende adecuar sus análisis a los (...) contenidos estructurales y al significado de los teoremas científicos, acaba disolviendo estos en meras correspondencias formales. La teoría del cierre categorial, en cambio, se adscribe a un constructivismo circularista que permite entender los dogmas sobre la estructura del ADN como si fueran identidades sintéticas materiales sin desdeñar por ello los aspectos pragmáticos, históricos y sociales, que valoran en su justa medida las aportaciones del grupo Fago, de Watson y Crick, de Pauling o de las universidades implicadas. (shrink)

La edición genética tiene muchas aplicaciones en casi todos los ámbitos de la sociedad, pero también puede tener consecuencias impredecibles. La edición del genoma de la línea germinal humana es el centro de una discusión mundial. Debido al creciente número de cuestionamientos científicos, éticos y políticos, muchos sin una respuesta concreta, el consenso de la comunidad científica manifiesta que sería inapropiado modificar genéticamente embriones humanos. Se considera necesario un debate serio y abierto para decidir si se debe suspender o (...) fomentar la investigación en este sentido. En el presente documento, se exponen algunos argumentos audaces a favor de la eliminación de los genes nocivos del genoma humano y los riesgos que supone el eugenismo liberal. (shrink)

Genetic studies of present human populations are very useful to understand the history of modern Human migrations throughout the world, especially when the results are compared with the information provided by historical linguistics and archaelogy. However, an inaccurate methodology is commonly applied to the analysis of the most recent molecular data and may lead to some erroneous conclusions on our first origins.

Este artigo discute o conceito de herdabilidade, empregado pela genética do comportamento, genética molecular e a teoria da herdabilidade, sob a perspectiva do modelo reticulado de racionalidade científica, de Larry Laudan. Analisa os argumentos contrários à utilização do termo herdabilidade focando principalmente nos resultados de experimentos da genética do comportamento. Conclui que algumas críticas ao termo herdabilidade são válidas tais como o termo poder ser confuso para o público em geral, mas podem ser extremas como as (...) que propõem sua extinção. A análise desenvolvida leva à conclusão de que a herdabilidade, tanto pela genética do comportamento, quanto pela genética molecular, é útil para seus respectivos fins. Os autores consideram que ao invés de ser extinto, o termo pode ser utilizado considerando mais análises, resultados e conclusões, sendo, portanto, essa a escolha mais racional e progressiva. (shrink)

El discurso biológico de Ayala se centra en estas tres cuestiones: 1) El hecho de la evolución. 2) Historia de la evolución. 3) Mecanismos del desarrollo y cambio evolutivos. El hecho determinante y cierto, según Ayala, es la evidencia de relaciones entre todos los organismos debidas a una común descendencia con modificaciones como lo han demostrado con abundancia la Paleontología, Anatomía comparada, Biogeografía, Embriología, Genética Molecular, Bioinformática y otras disciplinas biológicas que nos llevan a la afirmación de que (...) el hecho de la evolución de los seres vivos tiene el mismo grado de certeza que poseen los hechos históricos y científicos ampliamente confirmados. Para Ayala, explicaciones acerca del origen del mundo, del hombre y de otras criaturas se encuentran en todas las culturas. Tras la publicación del Origen de las Especies de C. Darwin en 1859, se produce gran polémica en los medios científicos, culturales y religiosos, pero pasado un período de maduración, el darwinismo logra ser aceptado especialmente bajo las formas de Neo-darwinismo y Teoría Sintética. Otro asunto muy distinto son las diversas teorías y micro-teorías que se proponen para explicar los mecanismos de la evolución de los organismos vivos que presentan todavía profundas lagunas, deficiencias y controversias que han provocado la aparición de teorías alternativas. No obstante, el darwinismo moderno constituye un peldaño importante en la reconstrucción del sinuoso y complejo proceso evolutivo de la vida a través de millones de años acudiendo a una razonable explicación causal sin que esto atente contra ningún supuesto religioso. (shrink)

The consolidation of the informational paradigm in molecular biology research concluded on a system to convert the epistemic object into an operational technological object and a stable epistemic product. However, the acceptance of the informational properties of genetic acids failed to clarify the meaning of the concept of information. The “information”’ as a property of the genetic molecules remained as an informal notion that allows the description of the mechanism of inheritance, but it was not specified in a logic–semantic (...) structure. The metaphorical implications associated with the idea of genes as molecules with meaning, questioned the linguistics that seemed too foreign to molecular biology. A reformulation of the concept of information in molecular biology was developed upon the theory of Claude Shannon. The node for the structural coupling between biology, physics and information theory was the identification of an analog structure between the coded messages of Shannon’s theory. (shrink)

La humanidad no solo ha evolucionado, sino que continúa evolucionando. ¿Hacia dónde va la evolución humana? La evolución biológica está dirigida por la selección natural, que no es un proceso benevolente que guíe a las especies hacia un éxito seguro. El resultado final puede ser la extinción. Los avances en genética, biología molecular y biomedicina han hecho posible manipular, rápida y efectivamente, la constitución genética de la humanidad. La terapia genética puede ser somática, o germinal. No (...) hay intervenciones de terapia germinal que estén siendo consideradas actualmente por científicos, médicos o compañías farmacéuticas. La clonación de humanos puede también referirse a clonación terapéutica o de individuos. Se han avanzado propuestas sugiriendo clonar individuos de gran capacidad intelectual o artística, o de virtud eminente. Tales propuestas utópicas son sumamente desafortunadas. No es posible clonar un individuo humano, aun si se clona su genoma. De genomas idénticos, desarrollados en contextos diferentes, familiares, sociales y culturales, pueden resultar individuos totalmente diferentes. Además, entran en juego consideraciones éticas, sociales y religiosas cuando se examina si una persona puede o debe ser clonada. (shrink)

Nos ocupamos de la controversia científica sobre la plausibilidad del seleccionismo génico. En primer lugar, mostramos que esta controversia parece estar estancada en su conjunto y particularmente sobre la cuestión central: si los genes son el objeto de la selección natural. En segundo lugar, sostenemos que el estancamiento sobre esta cuestión se explica en buena medida porque las partes en disputa están posicionadas sobre modos distintos de comprender la genética. Finalmente, argumentamos que la controversia podría avanzar si se enfrentara (...) un asunto muy problemático que, a pesar de su relevancia, ha sido relegado a un segundo plano: cómo definir “gen” en términos moleculares. (shrink)

The Genotype-Phenotype (G-P) distinction was proposed in the context of Mendelian genetics, in the wake of late 19th century studies about heredity. In this paper, we provide a conceptual analysis that highlights that the G-P distinction was grounded on three pillars: observability, transmissibility, and causality. Originally, the genotype is the non-observable and transmissible cause of the phenotype, which is its observable and non-transmissible effect. We argue that the current developments of biology have called the validity of such pillars into question. (...) First, molecular biology has unveiled the putative material substrate of the genotype (qua DNA), making it an observable object. Second, numerous findings on nongenetic heredity suggest that some phenotypic traits can be directly transmitted. Third, recent organicist approaches to biological phenomena have emphasized the reciprocal causality between parts of a biological system, which notably applies to the relations between genotypes and phenotypes. As a consequence, we submit that the G-P distinction has lost its general validity, although it can still apply to specific situations. This calls for forging new frameworks and concepts to better describe heredity and development. (shrink)

The rapidly changing field of genetics affects society through advances in health-care and through implications of genetic research. This study addresses the impacts of new genetic discoveries and technologies on different segments of today's society. The book begins with a chapter on genetic complexity, and subsequent chapters discuss moral and ethical questions arising from today's genetics from the perspectives of health care professionals, the media, the general public, special interest groups and commercial interests.

Despite the transformation in biological practice and theory brought about by discoveries in molecular biology, until recently philosophy of biology continued to focus on evolutionary biology. When the Human Genome Project got underway in the late 1980s and early 1990s, philosophers of biology -- unlike historians and social scientists -- had little to add to the debate. In this landmark collection of essays, Sahotra Sarkar broadens the scope of current discussions of the philosophy of biology, viewing molecular biology (...) as a unifying perspective on life that complements that of evolutionary biology. His focus is on molecular biology, but the overriding question behind these papers is what molecular biology contributes to all traditional areas of biological research.Molecular biology -- described with some foresight in a 1938 Rockefeller Foundation report as a branch of science in which "delicate modern techniques are being used to investigate ever more minute details" -- and its modeling strategies apparently argue in favor of physical reductionism. Sarkar's first three chapters explore reductionism -- defending it, but cautioning that reduction to molecular interactions is not necessarily a reduction to genetics. The next sections of the book discuss function, exploring how functional explanations pose a problem for reductionism; the informational interpretation of biology and how it interacts with reductionism; and the tension between the unifying framework of molecular biology and the received framework of evolutionary theory. The concluding chapter is an essay in the emerging field of developmental evolution, exploring what molecular biology may contribute to the transformation of evolutionary theory as evolutionary theory takes into account morphogenetic development. (shrink)

There is consensus within the chemosciences that olfactory perception is of the molecular structure of chemical compounds, yet within philosophical theories of smell there is little agreement about the nature of smell. The paper critically assesses the current state of debate regarding smells within philosophy in the hopes of setting it upon firm scientific footing. The theories to be covered are: Naïve Realism, Hedonic Theories, Process Theory, Odor Theories, and non-Objectivist Theories. The aforementioned theories will be evaluated based on (...) their explanations of the (a) the olfactory quality of a smell, (b) smells as distal entities, and (c) our experience of smells as intentional objects. The paper concludes with a defense of Molecular Structure Theory that demonstrating its superiority in accounting for each of these three aspects of smell. (shrink)

Philosophical discussion of molecular and developmental biology began in the late 1960s with the use of genetics as a test case for models of theory reduction. With this exception, the theory of natural selection remained the main focus of philosophy of biology until the late 1970s. It was controversies in evolutionary theory over punctuated equilibrium and adaptationism that first led philosophers to examine the concept of developmental constraint. Developmental biology also gained in prominence in the 1980s as part of (...) a broader interest in the new sciences of self-organization and complexity. The current literature in the philosophy of molecular and developmental biology has grown out of these earlier discussions under the influence of twenty years of rapid and exciting growth of empirical knowledge. Philosophers have examined the concepts of genetic information and genetic program, competing definitions of the gene itself and competing accounts of the role of the gene as a developmental cause. The debate over the relationship between development and evolution has been enriched by theories and results from the new field of 'evolutionary developmental biology'. Future developments seem likely to include an exchange of ideas with the philosophy of psychology, where debates over the concept of innateness have created an interest in genetics and development. (shrink)

In this fascinating study, the author analyzes the conceptual roots of molecular biology and the social matrix in which it was developed.

Część II pracy objaśnia molekularne podłoże pamięci w oparciu o założenia Neuro-Elektro- Dynamiki postulowanej przez Aura i Yoga. Wskazano na biofizyczne mechanizmy generacji wspomnień, refleksji i odczuć dzięki efatycznym sprzężeniom synaptycznym, spełniającym wymagania indukowania impresjonów Vadakkana. Wykazano, że działanie mechanizmu selekcyjnego WTA może być dobrym modelem opisującym funkcję przełączania uwagi. Wskazano na relacje między pamięcią roboczą, krótkoterminową i trwałą i ich spójność z molekularnymi procesami zapamiętywania i rozpoznawania wzorców. Wskazano, że trwała pamięć epizodyczna wymaga konwersji sekwencji czasowych sygnałów bottom-up do (...) rozkładu przestrzennego tworzącego impresjony dynamiczne. Odwrotna transformacja tych impresjonów umożliwia przypominanie epizodów z przeszłości. Omówiono znaczenie wrodzonych struktur sieci neuronowych zapewniających dziedziczenie zachowań instynktownych. Struktury te nie wykluczają zachowania plastyczności umysłu umożliwiającej efektywne uczenie. (shrink)

Resenha : Engenharia Genética: busca da mercadoria perfeita? - SANDEL, Michael J. Contra a Perfeição: ética na era da engenharia genética. 1ª.ed. Tradução por Ana Carolina Mesquita. Rio de janeiro: Civilização Brasileira, 2013. 160p.

_Philosophy of Molecular Medicine: Foundational Issues in Theory and Practice_ aims at a systematic investigation of a number of foundational issues in the field of molecular medicine. The volume is organized around four broad modules focusing, respectively, on the following key aspects: What are the nature, scope, and limits of molecular medicine? How does it provide explanations? How does it represent and model phenomena of interest? How does it infer new knowledge from data and experiments? The essays (...) collected here, authored by prominent scientists and philosophers of science, focus on a handful of mainstream topics in the philosophical literature, such as _causation_, _explanation_, _modeling_, and _scientific inference_. These previously unpublished contributions shed new light on these traditional topics by integrating them with problems, methods, and results from three prominent areas of contemporary biomedical science: _basic research_, _translational_ and _clinical research_, and _clinical practice_. (shrink)

Biologists and historians often present natural history and molecular biology as distinct, perhaps conflicting, fields in biological research. Such accounts, although supported by abundant evidence, overlook important areas of overlap between these areas. Focusing upon examples drawn particularly from systematics and molecular evolution, I argue that naturalists and molecular biologists often share questions, methods, and forms of explanation. Acknowledging these interdisciplinary efforts provides a more balanced account of the development of biology during the post-World War II era.

This paper focuses on the consolidation of Molecular Evolution, a field originating in the 1960s at the interface of molecular biology, biochemistry, evolutionary biology, biophysics and studies on the origin of life and exobiology. The claim is made that Molecular Evolution became a discipline by integrating different sorts of scientific traditions: experimental, theoretical and comparative. The author critically incorporates Timothy Lenoir’s treatment of disciplines , as well as ideas developed by Stephen Toulmin on the same subject. On (...) their account disciplines are spaces where the social and epistemic dimensions of science are deeply and complexly interwoven. However, a more detailed account of discipline formation and the dynamics of an emerging disciplinary field is lacking in their analysis. The present essay suggests focusing on the role of scientific concepts in the double configuration of disciplines: the social/political and the epistemic order. In the case of Molecular Evolution the concepts of molecular clock and informational molecules played a central role, both in differentiating molecular from classical evolutionists, and in promoting communication between the different sorts of traditions integrated in Molecular Evolution. The paper finishes with a reflection on the historicity of disciplines, and the historicity of our concepts of disciplines. (shrink)

A seleção genética de embriões humanos algumas vezes é criticada porque se considera que de alguma maneira ela possa prejudicar os portadores de deficiências que já existem. O artigo defende que essa crítica é injustificada. A primeira seção apresenta as questões morais colocadas pelos portadores de deficiências. Em seguida, são apresentados os três argumentos contra a seleção de embriões baseados nos direitos dos portadores de deficiências – o Argumento do Apoio Social, o Argumento da Diversidade e o Argumento da (...) Ofensa. Dentre eles, o terceiro foi considerado o mais consiste e, por isso, a terceira seção é dedicada a sua análise, cuja conclusão é de que a seleção de embriões é consistente com o respeito aos direitos dos portadores de deficiências. (shrink)

Las nuevas posibilidades abiertas por la investigación científica, especialmente en el campo de la genética, por un lado generan interrogantes morales hasta ahora desconocidos y, por otro, nos obligan a reformular de una manera totalmente nueva cuestiones y conceptos que hasta ahora funcionaban de forma adecuada. Así ocurre, por ejemplo, con las teorías de la justicia: estamos acostumbrados a que exista un acuerdo relativamente amplio en torno al concepto de persona, y la discusión se suele centrar en el tipo (...) de bienes que habrían de distribuirse entre un conjunto dado de individuos. Pero la posibilidad de transformar los talentos personales y, así, modificar algunos rasgos de nuestra población de acuerdo con criterios actuales, abre un importante debate en la medida en que dichos cambios pueden considerarse recursos y, así, objeto de redistribución. Por otro lado, el hecho de que ciertas alteraciones puedan o incluso deban realizarse con vistas al bien de futuros individuos conlleva el riesgo de que se abra paso una homogeneización social empobrecedora o de que se eliminen valiosas formas de vida y de cultura. Dado que esta incipiente posibilidad plantea aporías y amenazas inquietantes, la reflexión rigurosa constituye una herramienta crítica fundamental e imprescindible. (shrink)

The contribution of inherited non‐genetic factors to complex diseases is of great current interest. The ways in which mothers and fathers can affect their offspring's health clearly differ as a result of the intimate interactions between mother and offspring during pre‐ and postnatal life. There is, however, potential for some overlap in mechanisms, particularly epigenetic mechanisms. A small number of epidemiological studies and animal models have investigated the non‐genetic contribution of the parents to offspring health. Discovering new mechanisms of disease (...) inheritance is technically difficult, especially in genetically, socially and environmentally heterogeneous human populations. Therefore, rigorous experimental design, appropriate sample numbers and the use of high‐throughput technologies are necessary to provide convincing evidence. Based on recent examples from the literature, here we propose several ways to improve human studies that aim to identify the underlying mechanisms of transgenerational inheritance of metabolic disease. (shrink)

Advances in molecular biology have generally been taken to support the claim that biology is reducible to chemistry. I argue against that claim by looking in detail at a number of central results from molecular biology and showing that none of them supports reduction because (1) their basic predicates have multiple realizations, (2) their chemical realization is context-sensitive and (3) their explanations often presuppose biological facts rather than eliminate them. I then consider the heuristic and confirmational implications of (...) irreducibility and argue that purely biochemical approaches are likely to be unsound and to be unable to confirm an important range of statements. I conclude by sketching criteria for scientific unity that do not entail reducibility and yet leave an important place for identifying underlying mechanisms. Molecular biology, properly understood, provides an excellent paradigm of non-reductive unity between different explanatory levels. (shrink)

Biologists employ a suggestive metaphor to describe the complexities of molecular interactions within cells and embryos: cytological components are said to be part of “ecosystems” that integrate them in a complex network of relations with many other entities. The aim of this essay is to scrutinize the molecular ecosystem, a metaphor that, despite its longstanding history, has seldom be articulated in detail. I begin by analyzing some relevant analogies between the cellular environment and the biosphere. Next, I discuss (...) the applicability of the molecular ecosystem concept in actual scientific practice. (shrink)

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 Revolution in BrazilFélix Guattari and Suely Rolniktranslated by KarelClapshow and Brian HolmesYes, I believe that there is a multiple people, a people of mutants, apeople of potentialities that appears and disappears, that is embodied in social, literary, andmusical events.... I think that we're in a period of productivity, proliferation, creation, utterlyfabulous revolutions from the viewpoint of this emergence of a people. That's molecular revolution:it isn't a slogan or a program, it's something that I feel, that I live....--from (...) MolecularRevolution in BrazilFollowing Brazil's first democratic election after two decades of militarydictatorship, French philosopher Félix Guattari traveled through Brazil in 1982 with Brazilianpsychoanalyst Suely Rolnik and discovered an exciting, new political vitality. In the infancy of itsnew republic, Brazil was moving against traditional hierarchies of control and totalitarian regimesand founding a revolution of ideas and politics. Molecular Revolution in Brazil documents theconversations, discussions, and debates that arose during the trip, including a dialogue betweenGuattari and Brazil's future President Luis Ignacia Lula da Silva, then a young gubernatorialcandidate. Through these exchanges, Guattari cuts through to the shadowy practices of globalizationgone awry and boldly charts a revolution in practice.Assembled and edited by Rolnik, MolecularRevolution in Brazil is organized thematically; aphoristic at times, it presents a lesser-known,more overtly political aspect of Guattari's work. Originally published in Brazil in 1986 asMicropolitica: Cartografias do desejo, the book became a crucial reference for political movementsin Brazil in the 1980s and 1990s. It now provides English-speaking readers with an invaluablepicture of the radical thought and optimism that lies at the root of Lula's Brazil. Félix Guattari, post-'68 French psychoanalyst and philosopher, is the author of Anti-Oedipus, The Anti-Oedipus Papers, 2006), and other books. Semiotext haspublished the first two volumes of his complete essays, Chaosophy and Soft Subversions, and will publish the final volume, Chaos and Complexity, in 2008. Suely Rolnik is apsychoanalyst, cultural critic, and curator who lives and works in São Paulo, Brazil. She was aclose collaborator of Guattari during her exile in Paris from the military dictatorship inBrazil. (shrink)

This paper investigates what molecular biology has done for our understanding of the gene. I base a new account of the gene concept of classical genetics on the classical dogma that gene differences cause phenotypic differences. Although contemporary biologists often think of genes in terms of this concept, molecular biology provides a second way to understand genes. I clarify this second way by articulating a molecular gene concept. This concept unifies our understanding of the molecular basis (...) of a wide variety of phenomena, including the phenomena that classical genetics explains in terms of gene differences causing phenotypic differences. (shrink)

No presente estudo, discuto e sintetizo o conceito de célula vegetal de M. J. Schleiden e o conceito de animal elementar que elaboro a partir da ideia de “animal abstrato” sugerida por R. E. Grant. A elaboração e a interpretação que conduz a essa síntese é feita ampliando a ideia do desenvolvimento como um princípio regulador, proposta por E. Cassirer. Concebo tal ideia como expressão de uma racionalidade morfológica genética. O resultado geral obtido é que a célula vegetal e (...) o animal elementar são duas variações de uma mesma forma que exibe uma íntima relação estrutural-funcional, manifesta empiricamente em duas modalidades essenciais de vida, uma simples e singular e outra complexa e plural. A interação de ambas torna inteligível fenômenos básicos da vida vegetal e animal a partir de uma matriz genética comum. (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)

Perhaps the hottest topic in the philosophy of chemistry is that of the relationship between chemistry and physics. The problem finds one of its main manifestations in the debate about the nature of molecular structure, given by the spatial arrangement of the nuclei in a molecule. The traditional strategy to address the problem is to consider chemical cases that challenge the definition of molecular structure in quantum–mechanical terms. Instead of taking that top-down strategy, in this paper we face (...) the problem of the reduction of molecular structure to quantum mechanics from a bottom-up perspective: our aim is to show how the theoretical peculiarities of quantum mechanics stand against the possibility of molecular structure, defined in terms of the spatial relations of the nuclei conceived as individual localized objects. We will argue that, according to the theory, quantum “particles” are not individuals that can be identified as different from others and that can be reidentified through time; therefore, they do not have the ontological stability necessary to maintain the relations that can lead to a spatially definite system with an identifiable shape. On the other hand, although quantum chemists use the resources supplied by quantum mechanics with successful results, this does no mean reduction: their “approximations” add certain assumptions that are not justified in the context of quantum mechanics or are even inconsistent with the very formal structure of the theory. (shrink)