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Regularities of context-dependent codon bias in eukaryotic genes
Alexei Fedorov1, Serge Saxonov, Walter Gilbert
1Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA. afedorov@fas.harvard.edu
Nucleic Acids Research
|February 28, 2002
Summary
The nucleotide following a codon significantly impacts codon usage bias, known as the N1 context. This bias is prevalent across four eukaryotic genomes and is not always explained by overall genome composition.
Area of Science:
- Genomics
- Molecular Biology
- Bioinformatics
Background:
- Codon usage bias influences gene expression.
- The N1 context, the nucleotide following a codon, is a key factor in synonymous codon selection.
- Understanding codon usage patterns is crucial for gene function and evolution.
Purpose of the Study:
- To investigate the prevalence and characteristics of N1 context-dependent codon bias in four diverse eukaryotic genomes.
- To determine if genome-wide oligonucleotide composition explains observed codon bias.
- To identify regularities in codon bias based on nucleotide composition and N1 context.
Main Methods:
- Analysis of codon relative abundance in genes from Homo sapiens, Drosophila melanogaster, Caenorhabditis elegans, and Arabidopsis thaliana.
- Comparison of codon N1 context bias with 4mer oligonucleotide frequencies across entire genomes.
- Application of ranking statistics to compare context-dependent codon biases within synonymous groups.
Main Results:
- Over 90% of codons across all studied eukaryotes exhibit statistically significant N1 context-dependent codon bias.
- In approximately 50% of cases, this bias could not be attributed to the overall genome's sequence composition.
- A statistically significant correlation was found between the relative abundances of codons sharing identical second and third positions and the same N1 context.
Conclusions:
- N1 context-dependent codon bias is a widespread phenomenon in eukaryotes.
- Genome composition alone does not fully explain context-dependent codon bias.
- Regular patterns exist in N1 context-dependent codon bias related to codon nucleotide composition.