Processes of genome evolution reflected by base frequency differences among Serratia marcescens genes

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• The G+C content of DNA sequences can be influenced by mutation pressures and natural selection.
• Synonymous codons within genes can exhibit varying G+C content.
• Non-coding DNA regions are often considered less constrained by selection.

Purpose of the Study:

• To investigate the variation in G+C content at silent sites within Serratia marcescens genes.
• To determine the factors influencing G+C content, including mutation pressure and natural selection.
• To compare the G+C content of non-coding sequences with that of silent sites.

Main Methods:

• Analysis of G+C content across various Serratia marcescens genes.
• Comparison of G+C content between coding silent sites and non-coding regions.
• Statistical evaluation of the interplay between mutation and selection pressures.

Main Results:

• Significant variation in G+C content was observed among silent sites of Serratia marcescens genes.
• The G+C content appears to be shaped by a balance between mutation towards higher G+C and selection acting on codon usage.
• Non-coding sequences exhibited substantially lower G+C content compared to silent sites.

Conclusions:

• G+C content in Serratia marcescens is a dynamic property influenced by evolutionary forces.
• Natural selection plays a role in constraining codon choice, even at silent sites.
• Non-coding regions may be subject to different evolutionary pressures than coding silent sites.