On an RNA-Membrane Protogenome

Efficient evolution exists before DNA, else the DNA genome itself could not evolve. Current data suggest RNA-membranes for this role. Selected RNAs bind well to phospholipid bilayers; randomized sequences do not. No repeated sequences are evident in selected binding RNAs. This implies small and vari...

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Main Author: Michael Yarus
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Life
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Online Access:https://www.mdpi.com/2075-1729/15/5/692
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author Michael Yarus
author_facet Michael Yarus
author_sort Michael Yarus
collection DOAJ
description Efficient evolution exists before DNA, else the DNA genome itself could not evolve. Current data suggest RNA-membranes for this role. Selected RNAs bind well to phospholipid bilayers; randomized sequences do not. No repeated sequences are evident in selected binding RNAs. This implies small and varied membrane-affinity motifs. Such binding sequences are partially defined. Phospholipid-bound RNAs require divalents like Mg<sup>2+</sup> and/or Ca<sup>2+</sup>, preferring more ordered bilayers: gel, ripple, or rafted membranes, in that order. RNAs also bind and stabilize bent or sharply deformed bilayers. RNA binding without divalents extends to negatively charged membranes formed from simpler anionic phospholipids and to plausibly prebiotic fatty acid bilayers. RNA-membranes frequently retain RNA solution functions: base pairing, passive transport of tryptophan, specific affinity for arginine side chains, and ribozymic ligase catalysis. Membrane-bound RNAs with several biochemical functions, linked by specific base-pairing, are readily constructed. Given these data, genetic roles seem feasible. RNA activities often require few nucleotides, easily joined in a small RNA. Base-paired groups of such RNAs can also be purposeful, joining related functions. Complex functions can therefore require only replication of short RNAs. RNA-membranes potentially segregate accurately during cell division and quickly evolve through new base pairings. Accordingly, ancient RNA-membranes could act as a protogenome, supporting encoded RNA expression, inheritance, and evolution before the DNA genome: for example, supporting organized biochemistry, coded translation, and a Standard Genetic Code.
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spelling doaj-art-c3025ccaddfb41e3bb0a02163a9067d22025-08-20T03:47:54ZengMDPI AGLife2075-17292025-04-0115569210.3390/life15050692On an RNA-Membrane ProtogenomeMichael Yarus0Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USAEfficient evolution exists before DNA, else the DNA genome itself could not evolve. Current data suggest RNA-membranes for this role. Selected RNAs bind well to phospholipid bilayers; randomized sequences do not. No repeated sequences are evident in selected binding RNAs. This implies small and varied membrane-affinity motifs. Such binding sequences are partially defined. Phospholipid-bound RNAs require divalents like Mg<sup>2+</sup> and/or Ca<sup>2+</sup>, preferring more ordered bilayers: gel, ripple, or rafted membranes, in that order. RNAs also bind and stabilize bent or sharply deformed bilayers. RNA binding without divalents extends to negatively charged membranes formed from simpler anionic phospholipids and to plausibly prebiotic fatty acid bilayers. RNA-membranes frequently retain RNA solution functions: base pairing, passive transport of tryptophan, specific affinity for arginine side chains, and ribozymic ligase catalysis. Membrane-bound RNAs with several biochemical functions, linked by specific base-pairing, are readily constructed. Given these data, genetic roles seem feasible. RNA activities often require few nucleotides, easily joined in a small RNA. Base-paired groups of such RNAs can also be purposeful, joining related functions. Complex functions can therefore require only replication of short RNAs. RNA-membranes potentially segregate accurately during cell division and quickly evolve through new base pairings. Accordingly, ancient RNA-membranes could act as a protogenome, supporting encoded RNA expression, inheritance, and evolution before the DNA genome: for example, supporting organized biochemistry, coded translation, and a Standard Genetic Code.https://www.mdpi.com/2075-1729/15/5/692RNA worldRNA9RNA10DNAlipidphospholipid
spellingShingle Michael Yarus
On an RNA-Membrane Protogenome
Life
RNA world
RNA9
RNA10
DNA
lipid
phospholipid
title On an RNA-Membrane Protogenome
title_full On an RNA-Membrane Protogenome
title_fullStr On an RNA-Membrane Protogenome
title_full_unstemmed On an RNA-Membrane Protogenome
title_short On an RNA-Membrane Protogenome
title_sort on an rna membrane protogenome
topic RNA world
RNA9
RNA10
DNA
lipid
phospholipid
url https://www.mdpi.com/2075-1729/15/5/692
work_keys_str_mv AT michaelyarus onanrnamembraneprotogenome