“Evolution of life on Earth” — including how life (as we know it) originated from a mixture of non-living chemicals — is within our purview of gene-environment interactions. In the past several decades, it has become genereally accepted that “RNA preceded the existence of DNA.” This latest review [attached] focuses on what likely occurred before the existence of RNA. First, there emerged micellar protocell precursors, much simpler than the more commonly studied vesicle-based protocells. This viewpoint is based on a growing body of evidence that lipid micelles are capable of harboring catalysis (i.e., acceleration of a chemical reaction by a catalyst), forming catalytic networks that undergo self-reproduction and pass compositional information from one “generation” to the next.
Authors therefore propose that micelles — comprising molecularly diverse amphiphiles [i.e., chemical compounds that possess both hydrophilic (polar, water-loving) and lipophilic (nonpolar, lipid-loving) properties] could be evolutionary precursors to more elaborate protocellular entities, en route to life as we know it. The attached review extends and fortifies Kauffman’s “Origin” scenario, whereby collectively autocatalytic sets (CAS) of small molecules could precede RNA.
Previously, it had been proposed that a highly suitable platform for embodying CAS could be “mutually catalytic lipid networks,” and it had been shown — via details of the graded autocatalysis replication domain (GARD) chemical kinetics model — how mixed lipid assemblies could undergo compositional self-reproduction. The currect study now focuses on the possibility that life began with nanoscopic (i.e., extremely small, on a scale of one-billionth of a meter) lipid micelles, and reveals how experimental evidence regarding micellar catalysis substantiates the authors’ predictions.
Finally, this latest review paper emphasizes that micellar origin of life is compatible with prebiotic “messy chemistry.” Thus, this paper lends credence to what is becoming a viable scenario for a “pre-RNA origin of life.” 😊
DwN
Nat Rev Chem, (2021) https://doi.org/10.1038/s41570-021-00329-7
Self-reproducing catalytic micelles as nanoscopic protocell precursors – Nature Reviews Chemistry
We propose that life originated in spontaneously formed catalytic lipid micelles. Accumulating experimental evidence shows that such micelles undergo compositional autocatalytic reproduction. Lipid-first constitutes a parsimonious alternative to the RNA-first scenario.
doi.org