Evaluation of Genome Size Correlation with Behavioral and Ecological Characteristics in the Pathogenic Bacteria

Increasing number of bacteria which their genome sequenced leads to wide spread utilization of this data. Use of genomic information is possible through the simultaneous application of bioinformatics and bacteriology. Bioinformatics study of pathogenic bacteria indicates significant variation in genome size. There are several hypotheses about the reason of this variety as well as the relationship between fundamental processes of bacteria and genome size. The aim of this study was to investigate the relationship between genetic characteristics and behavior of pathogenic bacteria and genome size. The genome sequence data of 100 species of pathogenic bacteria were collected from different sources. The association of genome size with some characteristics of pathogenic bacteria was evaluated. Data were analyzed using SPSS statistical software, version 19.0. A significant relation was observed between the genome sizes of pathogenic bacteria with regard to some genomic features including G+C % content, the total number of genes, proteins, pseudogenes, acquired genes and some behavioral and ecological characteristics of bacteria, such as mobility, host range and breathing. Gene distribution and percent of non-protein-coding DNA have no correlation with genome size. There is a high DNA flexibility in pathogenic bacteria, and the size of the DNA is decreased during the evolution. This may lead to loss of some genes and less often acquire genes. These factors cause a reduction in the number of proteins and G + C percentage of bacteria which may account for their habitat limitation.