Common Repeat Sequences in Bacterial Genomes
Repeat sequences are widely appearing in bacterial genomes. However, detailed functions and mechanisms of most repeats are still unknown. We explored four types of repeats in 58 fully sequenced bacterial genomes, including 60 chromosomal and 22 plasmid sequences. For each bacterial genome sequence, the repeat density in number and in length were both calculated and compared, and potential common repeats of four repeat types were also recognized. The results showed most chromosomal sequences contain repeat sequences and a large number of plasmid sequences do not have repeat sequences. The density of repeats is not correlated with either the current taxonomy or the genome size of bacteria. Only the reverse complement repeats are common in most bacterial genomes. The four types of repeats might be different in terms of functions, evolutions and mechanisms. For further investigations, the development of a new methodology with combined statistical analysis and detailed biological knowledge of each bacterial organism will be needed.