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Early evolution: prokaryotes, the new kids on the block
1Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand. anthony.poole@molbio.su.se
Summary
Challenging the prokaryote-first origin of life model, this study proposes that early life required a high-accuracy RNA replicase and a ribosome with a prior function. This RNA world model better explains eukaryotic features and the origin of life.
Area of Science:
- Origin of Life Studies
- Molecular Evolution
- Biochemistry
Background:
- Current models of life's origin often assume prokaryotes are the oldest life forms.
- This assumption complicates understanding the transition to complex life and explaining ancient eukaryotic features.
- Relic RNA species suggest an RNA world stage preceding protein evolution.
Purpose of the Study:
- To propose a new model for the origin of life.
- To explain the persistence of ancient RNA world features in eukaryotes.
- To reconcile the requirements for early RNA replication and ribosome function.
Main Methods:
- Inference from relic RNA species in modern organisms.
- Development of a theoretical model connecting RNA replicase and ribosome function.
- Analysis of RNA metabolism and genome structure in prokaryotes and eukaryotes.
Main Results:
- An RNA world likely required a high-accuracy RNA replicase before protein evolution.
- The ribosome's size suggests a function predating protein synthesis.
- A unified model explains early life transitions and eukaryotic RNA world vestiges.
Conclusions:
- The origin of life may not have started with prokaryotes.
- Eukaryotic features are better explained by a model emphasizing an early RNA world.
- Prokaryotic RNA evolution can be explained by r-selection and thermoreduction.