Assembly theory is a groundbreaking theoretical framework that bridges physics and biology, providing transformative insights into biological evolution and its place in universal physical laws. Its applications range from the search for extraterrestrial life to understanding the origin of life, and it is expected to reshape many fields of science.
An international team of researchers has developed a new theoretical framework that links physics and biology to provide a unified approach to understanding how complexity and evolution arise in nature. This new work on "assembly theory," published today (October 4) in the journal Nature, marks significant progress in our fundamental understanding of biological evolution and how it is governed by the physical laws of the universe.
Preliminary work and molecular assembly indexThe study builds on previous work by the research group, which developed assembly theory into an empirically proven method for detecting life, with implications for efforts to search for extraterrestrial life and evolve new life forms in the laboratory. In previous work, the team assigned molecules a complexity score called the molecular assembly index, based on the minimum number of bonding steps required to build the molecule. They show how this index can be measured experimentally and how high values can be associated with molecules of life.
Mathematical formalism in assembly theory
The new research introduces a mathematical formalism around a physical quantity called "assembly," which captures the degree of selection required to produce a complex set of objects based on their abundance and assembly index.
Professor Sarah Walker, a theoretical physicist and origin-of-life researcher at Arizona State University, explains: "Assembly theory provides a completely new perspective, allowing us to look at the same fundamental reality of physics, chemistry and biology from a different perspective. With this theory, we can start to close the gap between reductionist physics and Darwinian evolution - an important step towards unifying the fundamental theories of inert matter and living matter."
Applications and future potential
The researchers show how assembly theory can be applied to quantify selection and evolution in systems ranging from simple molecules to complex polymers and cellular structures. It explains both the discovery of new objects and the selection of existing ones, allowing for the unlimited increase in complexity that characterizes life and technology.
Professor Lee Cronin, chemist at the University of Glasgow and co-first author, said: "Assembly theory offers a completely new way of looking at the matter that makes up our world, defined not just by immutable particles but also by the memory required to build objects through long-term selection. With further work, this approach has the potential to transform fields from cosmology to computer science. It represents a new frontier at the intersection of physics, chemistry, biology and information theory."
Deepen understanding
The researchers aim to further refine assembly theory, explore its applications in describing the characteristics of known and unknown life, and test hypotheses about how life arises from nonliving matter. "An important feature of the theory is that it can be tested experimentally," Cronin said. "This opens up the exciting possibility of using assembly theory to design new experiments that could address questions about the origin of life by creating living systems from scratch in the laboratory."
This theory opens up many new questions and research directions at the boundaries of physics and life sciences. Taken together, assembly theory promises to provide profound new insights into the physical basis of biological complexity and evolutionary innovation.