Intellectual frameworks to understand complex biochemical systems at the origin of life

Understanding the emergence of complex biochemical systems, such as protein translation, is a great challenge. Although synthetic approaches can provide insight into the potential early stages of life, they do not address the equally important question of why the complex systems of life would have evolved. In particular, the intricacies of the mechanisms governing the transfer of information from nucleic acid sequences to proteins make it difficult to imagine how coded protein synthesis could have emerged from a prebiotic soup. Here we discuss the use of intellectual frameworks in studying the emergence of life. We discuss how one such framework, namely the RNA world theory, has spurred research, and provide an overview of its limitations. We suggest that the emergence of coded protein synthesis could be broken into experimentally tractable problems by treating it as a molecular bricolage—a complex system integrating many different parts, each of which originally evolved for uses unrelated to its modern function—to promote a concrete understanding of its origin. It has been challenging to rationalize the emergence of complex biochemical systems because many parts with different functions needed to come together. This Perspective proposes a molecular bricolage—an evolutionary tinkering involving parts that initially evolved for unrelated functions—to provide an intellectual framework to study the origin of protein translation.