Life’s Dual Nature: A Way Out of the Impasse of the Gene-Centred ‘Versus’ Complex Systems Controversy on Life

Abstract

Living cells and organisms are complex physical systems. Does their organization or complexity primarily rely on the intra-molecular crystalline structure of genetic nucleic acid sequences? Or is it, as critics of the ‘gene-centred’ perspective claim, predominantly a result of the inter- and supra-molecular—thus ‘holistic’—network dynamics of genetic and various extra-genetic factors? The twentieth-century successes in several branches of genetics caused intensive focus on the causal role of genes in the biochemistry, development and evolution of living organisms, resulting in a relative abstraction or even neglect of life’s complex systems dynamics. Today, however, partly due to the success of systems biology, a number of authors defend life’s systems complexity while criticizing the gene-centred approach. Here, we offer a way out of the impasse of the gene-centred ‘versus’ complex systems perspective to arrive at a more balanced and complete understanding of life’s multifaceted nature. After sketching the conceptual and historical background of the controversy, we show how the present state of knowledge in biology vindicates both the holistically complex and gene-centred nature of life on Earth, but decisively falsifies extreme genetic ‘determinism’ and ‘reductionism’ as well as extreme ‘gene-de-centrism’. Contrary to what is often claimed, the fact that genes are one among many extra-genetic causal factors contributing to the biochemistry and development of cells and organisms, only undermines or falsifies genetic determinism and reductionism but not necessarily gene-centrism. Some implications for evolutionary theory, i.e. for the controversy between the Modern Synthesis and an ‘Extended Synthesis’ , are outlined.