The emergence of eukaryotes as an evolutionary algorithmic phase transition

Area of Science:

• Evolutionary biology
• Genomics
• Molecular evolution

Background:

• The origin of eukaryotic cells is a pivotal event in evolution, enabling multicellularity.
• Understanding the regulatory mechanisms that facilitated this increase in complexity is crucial.

Purpose of the Study:

• To investigate the evolutionary transformation of gene activity regulation during the origin of eukaryotes.
• To analyze protein and gene length distributions across diverse species.

Main Methods:

• Analysis of protein and gene length distributions for 6,519 species.
• Development of a simple model to explain observed length relationships.
• Examination of evolutionary trends from prokaryotes to eukaryotes.

Main Results:

• A scale-invariant relationship between mean gene length and variance was observed across evolutionary history.
• Prokaryotic protein length scaled with gene growth, but eukaryotic mean protein length stabilized around 500 amino acids.
• Gene growth in eukaryotes predominantly involved noncoding sequences for gene regulation.

Conclusions:

• The stabilization of protein length at the eukaryotic origin suggests a shift in evolutionary strategy.
• Noncoding DNA expansion played a critical role in regulating gene activity in early eukaryotes.
• This transition may represent an algorithmic phase transition driven by constraints on protein size.