Advances in molecular biological research in the latter half of the twentieth century have made the story of the gene vastly complicated: the more we learn about genes, the less sure we are of what a gene really is. Knowledge about the structure and functioning of genes abounds, but the gene has also become curiously intangible. This collection of essays renews the question: what are genes? Philosophers, historians and working scientists re-evaluate the question in this volume, treating the gene as (...) a focal point of interdisciplinary and international research. It will be of interest to professionals and students in the philosophy and history of science, genetics and molecular biology. (shrink)

Over the decades, there has been substantial empirical evidence showing that the unity of species cannot be maintained by gene flow. The biological species concept is inconclusive on this point. The suggestion is made that the unity of species is maintained rather by selection constantly spreading new alleles throughout the species, or bygene circulation. There is a lack in conceptual distinction between gene flow and gene circulation which lies at the heart of the problem. The concept of gene circulation also (...) sheds some new light on the problem of typology and on such a broad concept as evolution. A new species definition is proposed. (shrink)