Prokaryotic nucleotide composition is shaped by both phylogeny and the environment

Area of Science:

• Microbiology
• Genomics
• Bioinformatics

Background:

• Prokaryotic genome nucleotide composition exhibits significant variation, with the underlying causes being a long-standing debate.
• Guanine and Cytosine (GC) content is a fundamental characteristic of DNA, influencing genome stability and gene regulation.

Purpose of the Study:

• To investigate the relative contributions of phylogeny and environment in shaping prokaryotic genome nucleotide composition.
• To identify specific environmental factors that drive variations in GC-content across different prokaryotic habitats.

Main Methods:

• Analysis of extensive metagenomic and whole-genome sequencing data from diverse prokaryotic populations.
• Statistical comparison of nucleotide composition (GC-content) across various phylogenetic groups and environmental niches.

Main Results:

• Both phylogeny and environment significantly influence prokaryotic nucleotide composition.
• Distinct phylogenetic groups show characteristic mean GC-values and variation levels across environments.
• Environmental factors drive GC-content variation independently of phylogenetic composition, even within similar environments like the human gut.

Conclusions:

• Prokaryotic genome nucleotide composition is a complex interplay between evolutionary lineage and environmental pressures.
• Environmental influences on nucleotide content are more subtle and pervasive than previously recognized, impacting microbial communities even within seemingly uniform habitats.