O código genético é degenerado, isto é, o mesmo amino ácido pode ser codificado por vários codons. Apesar de codificarem o mesmo amino ácido, estes codons sinônimos não são utilizados da mesma forma em genomas diferentes, e mesmo em um único genoma o padrão de uso dos codons sinônimos pode variar muito entre os genes, ou ainda ao longo de um único gene. Com a recente introdução de seqüências ge...

UNLABELLED It is well known that an amino acid can be encoded by more than one codon, called synonymous codons. The preferential use of one particular codon for coding an amino acid is referred to as codon usage bias (CUB). A quantitative analytical method, CUB and a related tool, Codon Adaptative Index have been applied to comparatively study whole genomes of a few pathogenic Trypanosomatid sp...

To study the roles of translational accuracy, translational efficiency, and the Hill-Robertson effect in codon usage bias, we studied the intragenic spatial distribution of synonymous codon usage bias in four prokaryotic (Escherichia coli, Bacillus subtilis, Sulfolobus tokodaii, and Thermotoga maritima) and two eukaryotic (Saccharomyces cerevisiae and Drosophila melanogaster) genomes. We genera...

We propose a simple, sensitive measure of synonymous codon usage bias, the Relative Codon Adaptation Index (rCAI), as a way to discriminate better between highly biased and unbiased regions, compared with the widely used Codon Adaptation Index (CAI). CAI is a geometric mean of the relative usage of codons in a gene, and is calculated using the codon usage table trained with a set of highly expr...

Although the mapping of codon to amino acid is conserved across nearly all species, the frequency at which synonymous codons are used varies both between organisms and between genes from the same organism. This variation affects diverse cellular processes including protein expression, regulation, and folding. Here, we mathematically model an additional layer of complexity and show that individu...

Codon usage bias, the preferential use of particular codons within each codon family, is characteristic of synonymous base composition in many species, including Drosophila, yeast, and many bacteria. Preferential usage of particular codons in these species is maintained by natural selection acting largely at the level of translation. In Drosophila, as in bacteria, the rate of synonymous substit...

Submitted for the MAR07 Meeting of The American Physical Society A Model of Codon Usage Bias MORTEN KLOSTER, CHAO TANG, UCSF — The genetic code is degenerate; most amino acids can be encoded by from two to as many as six different codons. While one might expect these codons to be used with equal frequency, this turns out not to be the case—not only are some codons favored over others, but their...

Codon usage bias measure is defined through the mutual entropy calculation of real codon frequency distribution against the quasi-equilibrium one. This latter is defined in three manners: (1) the frequency of synonymous codons is supposed to be equal (i.e., the arithmetic mean of their frequencies); (2) it coincides to the frequency distribution of triplets; and, finally, (3) the quasi-equilibr...

Synonymous codons are unevenly distributed among genes, a phenomenon termed codon usage bias. Understanding the patterns of codon bias and the forces shaping them is a major step towards elucidating the adaptive advantage codon choice can confer at the level of individual genes and organisms. Here, we perform a large-scale analysis to assess codon usage bias pattern of pyrimidine-ending codons ...

TP53 gene is known as the "guardian of the genome" as it plays a vital role in regulating cell cycle, cell proliferation, DNA damage repair, initiation of programmed cell death and suppressing tumor growth. Non uniform usage of synonymous codons for a specific amino acid during translation of protein known as codon usage bias (CUB) is a unique property of the genome and shows species specific d...