Repeated sequences in bacterial chromosomes and plasmids: a glimpse from sequenced genomes

To gain insight into the extent of exact DNA repeats in sequenced bacterial genomes and their plasmids, we analyzed the collection of completely seque nced bacterial genomes available at GenBank using the program Miropeats. Th is program draws graphical representations of exact DNA repeats in whole ge nomes. In this work, we present maps showing the extent and type (inverted or direct) of exact DNA repeats longer than 300 bp for the whole collection . These repeats may participate in a variety of events relevant for bacteri al genome plasticity, such as amplifications, deletions, inversions, and tr anslocations (via homologous recombination), as well as transposition. Addi tionally, we review recent data showing that high-frequency architectural v ariations in genomic structure occur at both the interspecies and interstra in levels. (C) 1999 Editions scientifiques et medicales Elsevier SAS.