Codon usage and sequence analysis of shigella flexneri genes

الملخص EN

The nucleotide sequences of fifty genes of Shigella flexneri 5 strains 8401 were analyzed.

The very lowly expressed genes (nine genes) have P2 value range of (0.29-0.42) while moderately low expressed genes (thirteen genes) have P2 range of (0.42-0.5).

Highly expressed genes (sixteen genes) range between (0.50-0.63) and very highly expressed genes (twelve genes) range was (0.63-0.85).

GC % content fluctuated from 44 %-55 % with a mean value of 52 % indicating the nucleotides G and C slightly higher than A and T and it is a GC rich microorganism.

The points of the ENc plot against GC3 composition are quite spreaded which suggest that there are other contributors to the codon usage pattern besides the genomic composition.

CAI values clearly parallel levels of gene expressions so highly expressed genes have higher CAI values.