Compositional patterns in the genomes of unicellular eukaryotes.

Area of Science:

• Genomics
• Evolutionary Biology
• Molecular Biology

Background:

• Multicellular eukaryotic genomes exhibit compartmentalization into isochores, DNA regions with distinct GC levels, gene density, and chromatin properties.
• The evolutionary origin of this compartmentalized genome organization remains an open question.

Purpose of the Study:

• To investigate the evolutionary history of eukaryotic genome compartmentalization.
• To determine if compositional compartmentalization is a conserved feature across different eukaryotic lineages, including unicellular organisms.

Main Methods:

• Analysis of whole-genome sequences from a representative sample of unicellular eukaryotes.
• Examination of DNA compositional patterns, focusing on GC level distribution and compartmentalization.

Main Results:

• Genomes of unicellular eukaryotes display a wide range of average GC levels (19%-60%).
• Individual genomes show highly diverse compositional patterns, varying from narrow to complex.
• All tested unicellular eukaryotic genomes demonstrate compositional compartmentalization.

Conclusions:

• Unicellular eukaryotes exhibit broad GC level ranges and diverse compositional patterns, reflecting phylogenetic and environmental diversity.
• The presence of compositional compartmentalization in all tested unicellular eukaryotes suggests it is an ancient feature of eukaryotic genomes.
• This compartmentalization represents a fundamental difference between eukaryotic and prokaryotic genome organization.