Biologia Molecular

Molecular Biology (Stanford Encyclopedia of Philosophy)

29/07/11 12:57

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Molecular Biology
First published Sat Feb 19, 2005; substantive revision Wed Sep 9, 2009 The field of molecular biology studies macromolecules and the macromolecular mechanisms found inliving things, such as the molecular nature of the gene and its mechanisms of gene replication, mutation, and expression. Given the fundamental importance of these macromolecular mechanisms throughout the history of molecular biology, it will be argued that a philosophical focus on the concept of a mechanism generates the clearest picture of molecular biology's history, concepts, and case studiesutilized by philosophers of science. This encyclopedia entry is organized around these three themes. First, a historical overview of the developments in molecular biology from its origins to the present pays special attention to the features of this history referenced by philosophers. Philosophical analysis then turns to the key concepts in the field: mechanism, information, and the gene. Finally,philosophers have used molecular biology as a case study to address more general issues in the philosophy of science, such as theory reduction and scientific explanation, each of which are understood most clearly in molecular biology with a focus on the field's attention to mechanisms. 1. History of Molecular Biology 1.1 Origins 1.2 Classical Problems 1.3 Going Molecular 1.4 Going Genomic...andPost-Genomic 2. Concepts in Molecular Biology 2.1 Mechanism 2.2 Information 2.3 Gene 3. Molecular Biology and General Philosophy of Science 3.1 Theory Reduction and Integration of Fields 3.2 Explanation in Molecular Biology 4. Conclusion Bibliography Other Internet Resources Related Entries
http://plato.stanford.edu/entries/molecular-biology/ Página 1 de 43

Molecular Biology (StanfordEncyclopedia of Philosophy)

29/07/11 12:57

1. History of Molecular Biology
Despite its prominence in the contemporary life sciences, molecular biology is a relatively young discipline, originating in the 1930s and 1940s, and becoming institutionalized in the 1950s and 1960s. It should not be surprising, then, that many of the philosophical issues in molecular biology are closely intertwined withthis recent history. This section sketches four facets of molecular biology's development: its origins, its classical problems, its subsequent migration into other biological domains, and its more recent turn to genomics and post-genomics. The rich historiography of molecular biology can only be briefly utilized in this shortened history. (See, for example, Abir-Am 1985, 1987, 1994, 2006; Burian1993; de Chadarevian 2002, 2003; de Chadarevian and Gaudilliere 1996; de Chadarevian and Strasser 2002; Holmes 2001; Judson 1980, 1996; Kay 1993; Morange 1998; Olby 1979, 1990, 1994, 2003; Rheinberger 1997; Sapp 1992; Sarkar 1996a; Witkowski 2005; Zallen 1996. Also see autobiographical accounts by biologists, such as Brenner 2001; Cohen 1984; Crick 1988; Echols 2001; Jacob 1988; Kornberg 1989; Luria1984; Watson 1968, 2002, 2007; Wilkins 2003.)

1.1 Origins
The field of molecular biology arose from the convergence of work by geneticists, physicists, and structural chemists on a common problem: the structure and function of the gene. In the early twentieth century, although the nascent field of genetics was guided by Mendel's law of segregation (two alleles of a gene separate, i.e.,segregate, during the formation of the germ cells so that each germ cell has one but not the other) and law of independent assortment (genes in different linkage groups assort independently in the formation of germ cells), the actual mechanisms of gene reproduction, mutation and expression remained unknown. Thomas Hunt Morgan and his colleagues utilized the fruit fly, Drosophila, as a model organism to...