Genome-wide nucleotide bias does not significantly affect the relative amino acid composition

Tuesday, October 25, 2011 — Poster Session II
Noon – 2:00 p.m.	Natcher Conference Center	NIAID	GEN/GENOM-12

Authors

• V Nagarajan
• P Crompton
• D Hurt

Abstract

A wide range of bias in nucleotide composition exists among genomes. Additionally, the amino acid composition significantly differs in correlation with the organism’s nucleotide composition. Since the core cellular machinery of every organism is similar, we hypothesized that there has to be similarity among the relative proportion of amino acids at the genome level, irrespective of the organism’s bias in nucleotide composition. The literature and the corresponding data showed a correlation between nucleotide bias and amino acid composition. The data and the conclusions from previous literature showed significant difference among similar amino acids of extremely GC-biased organisms. All of those comparisons have been made between individual amino acids. We reproduced the amino acid frequency chart similar to one that was previously presented for two organisms with extreme GC-bias. A different look at the same data as a genome-wide profile clearly showed a significant similarity among the amino acid profiles of extremely GC-biased organisms. We generated the genome-wide nucleotide profile, codon usage profile and the amino acid profile for three organisms with a wide range of nucleotide composition. Our data showed that irrespective of the bias in nucleotide composition all of the organisms have a similar genome-wide amino acid profile.

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