Known examples of life all share the same core biochemistry going back to the last universal common ancestor (LUCA), but whether this feature is universal to other examples, including at the origin of life or alien life, is unknown. We show how a physics-inspired statistical approach identifies universal scaling laws across biochemical reactions that are not defined by common chemical components but instead, as macroscale patterns in the reaction functions used by life. The identified scaling relations can be used to predict statistical features of LUCA, and network analyses reveal some of the functional principles that underlie them. They are, therefore, prime candidates for developing new theory on the “laws of life” that might apply to all possible biochemistries…
“A critical question is whether the universality classes identified herein are a product of the shared ancestry of life. A limitation of the traditional view of biochemical universality is that universality can only be explained in terms of evolutionary contingency and shared history, which challenges our ability to generalize beyond the singular ancestry of life as we know it. Indeed, a set of closely related genomes will, by definition, share a high degree of universality in component enzyme functions. Phylogenetic effects would be a concern here too if we were claiming universality in terms of a specific set of unique enzyme functions as these then could be attributed to oversampling highly related genomes. Instead, we showed here that universality classes are not directly correlated with component universality, which is indicative that it emerges as a macroscopic regularity in the large-scale statistics of catalytic functional diversity. Furthermore, EC [enzyme class] universality cannot simply be explained due to phylogenetic relatedness since the range of total enzyme functions spans two orders of magnitude, evidencing a wide coverage of genomic diversity.”Gagler, D. C., Karas, B., Kempes, C. P., Malloy, J., Mierzejewski, V., Goldman, A. D., Kim, H., & Walker, S. I. (2022). Scaling laws in enzyme function reveal a new kind of biochemical universality. Proceedings of the National Academy of Sciences of the United States of America, 119(9), e2106655119.
The underlying issue may well be this: With the James Webb Space Telescope headed off to survey countless exoplanets, astrobiology (search for extraterrestrial life) is becoming cool. A strict neo-Darwinian approach, as in “All life unearth arose from a single cell” is, at best, inconvenient. At worst, a true bummer. The astrobiologist is going to be much happier with “prime candidates for developing new theory on the ‘laws of life’ that might apply to all possible biochemistries…” Life lesson: Researchers will sacrifice Darwinism pretty quickly when it is an actual impediment.
The paper is open access.