Molecular Evolution in Historical Perspective.

In the 1960s, advances in protein chemistry and molecular genetics provided new means for the study of biological evolution. Amino acid sequencing, nucleic acid hybridization, zone gel electrophoresis, and immunochemistry were some of the experimental techniques that brought about new perspectives to the study of the patterns and mechanisms of evolution. New concepts, such as the molecular evolutionary clock, and the discovery of unexpected molecular phenomena, like the presence of repetitive sequences in eukaryotic genomes, eventually led to the realization that evolution might occur at a different pace at the organismic and the molecular levels, and according to different mechanisms. These developments sparked important debates between defendants of the molecular and organismic approaches. The most vocal confrontations focused on the relation between primates and humans, and the neutral theory of molecular evolution. By the 1980s and 1990s, the construction of large protein and DNA sequences databases, and the development of computer-based statistical tools, facilitated the coming together of molecular and evolutionary biology. Although in its contemporary form the field of molecular evolution can be traced back to the last five decades, the field has deep roots in twentieth century experimental life sciences. For historians of science, the origins and consolidation of molecular evolution provide a privileged field for the study of scientific debates, the relation between technological advances and scientific knowledge, and the connection between science and broader social concerns.