Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
J Mol Evol. 2024 Oct;92(5):539-549. doi: 10.1007/s00239-024-10201-z. Epub 2024 Sep 8.
Abiogenesis is frequently envisioned as a linear, ladder-like progression of increasingly complex chemical systems, eventually leading to the ancestors of extant cellular life. This "pre-cladistics" view is in stark contrast to the well-accepted principles of organismal evolutionary biology, as informed by paleontology and phylogenetics. Applying this perspective to origins, I explore the paradigm of "Stem Life," which embeds abiogenesis within a broader continuity of diversification and extinction of both hereditary lineages and chemical systems. In this new paradigm, extant life's ancestral lineage emerged alongside and was dependent upon many other complex prebiotic chemical systems, as part of a diverse and fecund prebiosphere. Drawing from several natural history analogies, I show how this shift in perspective enriches our understanding of Origins and directly informs debates on defining Life, the emergence of the Last Universal Common Ancestor (LUCA), and the implications of prebiotic chemical experiments.
自生说是人们经常设想的一种线性、阶梯式的复杂化学系统的进化过程，最终导致了现存细胞生命的祖先。这种“前分类学”观点与古生物学和系统发生学所提供的生物进化生物学的公认原则形成鲜明对比。从这个角度来看起源，我探讨了“干细胞生命”的范例，该范例将自生说嵌入到遗传谱系和化学系统的多样化和灭绝的更广泛连续性中。在这个新的范例中，现存生命的祖先谱系与许多其他复杂的前生物化学系统一起出现，并依赖于这些系统，作为多样化和多产的前生物界的一部分。通过几个自然历史类比，我展示了这种观点的转变如何丰富了我们对起源的理解，并直接影响了关于定义生命、最后普遍共同祖先 (LUCA) 的出现以及前生物化学实验的意义的争论。
