Evolution of Genomic Base Composition: From Single Cell Microbes to Multicellular Animals

Area of Science:

• Evolutionary biology
• Genomics
• Microbial evolution

Background:

• Whole genome sequencing (WGS) has revealed insights into microbial evolution.
• Eukaryotic genome data is increasing, enabling comparative analyses.
• Genomic base composition dynamics vary across life's domains.

Purpose of the Study:

• To review evolutionary dynamics of base composition in prokaryotes and eukaryotes.
• To compare common and differing evolutionary mechanisms influencing genomic base composition.
• To highlight distinct evolutionary constraints on base composition in prokaryotes and eukaryotes.

Main Methods:

• Review of existing literature and genomic data.
• Comparative analysis of base composition evolutionary mechanisms.
• Examination of GC content correlations with genome size and other factors.

Main Results:

• Prokaryotes and eukaryotes exhibit both similarities and striking differences in genomic base composition evolution.
• Eukaryotes show GC-biased gene conversion (gBGC) increasing local GC content.
• Prokaryotic GC content increase appears driven by environment and selection, with AT-rich DNA uptake explaining negative GC3-genome size correlation.

Conclusions:

• Genomic base composition has evolved under different constraints in prokaryotes and eukaryotes.
• Mechanisms like gBGC in eukaryotes and environmental selection in prokaryotes drive base composition changes.
• Similar observed phenomena, such as negative GC3-genome size correlation, arise from distinct evolutionary pathways.