Abstract:
The obcell hypothesis is a proposed route for the RNA world to develop into a primitive cellular one. It posits that this transition began with the emergence of the proto-ribosome which enabled RNA to colonise the external surface of lipids by the synthesis of amphipathic peptidyl-RNAs. The obcell hypothesis also posits that the emergence of a predation-based ecosystem provided a selection mechanism for continued sophistication amongst early life forms. Here, I argue for this hypothesis owing to its significant explanatory power; it offers a rationale why a ribosome which initially was capable only of producing short non-coded peptides was advantageous and it forgoes issues related to maintaining a replicating RNA inside a lipid enclosure. I develop this model by proposing that the evolutionary selection for improved membrane anchors resulted in the emergence of primitive membrane pores which enabled obcells to gradually evolve into a cellular morphology. Moreover, I introduce a model of obcell production which advances that tRNAs developed from primers of the RNA world.
摘要:
obcell假说是RNA世界发展为原始细胞世界的拟议途径。假定这种转变始于原核糖体的出现,该核糖体使RNA能够通过两亲性肽基-RNA的合成而定居在脂质的外表面。obcell假说还认为,基于捕食的生态系统的出现为早期生命形式的持续发展提供了选择机制。这里,由于其重要的解释能力,我主张这一假设;它提供了一个基本原理,为什么最初只能产生短非编码肽的核糖体是有利的,并且它放弃了与在脂质外壳内维持复制RNA有关的问题。我通过提出对改进的膜锚的进化选择导致原始膜孔的出现来开发该模型,该原始膜孔使obcells逐渐进化为细胞形态。此外,我介绍了一个obcell生产模型,该模型促进了从RNA世界的引物开发的tRNA。