Genomic islands (GI) are formerly mobile genetic elements that have been integrated into an organism's genome. They encode a variety of different functions that depend largely on the environment of the organism, and can be involved in symbiosis or pathogenesis. Often, they confer on an organism fitness to occupy a particular ecological niche. (Hentschel et al., Microbes Infect. 2001 Jun;3(7):545-8.). A single mobile element can be found in many distantly related species. The lateral gene transfer of mobile elements occurs between different organisms and strains in a variety of ways: Transformation, Conjugation, and Transduction. Base Composition Analysis (G+C content, genome signature, codon usage) can be used to identify laterally transferred genes. Base composition analyses methods established by Samuel Karlin (Trends Microbiol. 2001 Jul;9(7):335-43.) were used to find atypical genes.

The following table contains records of GIs that have been identified in Streptococcus mutans using base composition analyses and BLAST taxonomy data. The genome coordinates, the value of each parameter and a measure of its deviation is provided for each island. The skew is the number of standard deviations from the genome mean value of the quantity measured. The Genomic Island ID is hyperlinked to a annotated GI record that contains more detailed information.

Gen. Island ID Start Stop %GC GC Skew Genome Signature Skew Codon Bias (Genome) Skew Codon Bias (Ribosomal) Skew Description 1 4663 14649 31.02 -1.59 142 0.26 284 -0.47 489 -0.12 cell division-related cluster 3 31163 61245 38.57 0.35 127 0.00 418 0.60 570 0.60 purine metabolism (pur) gene cluster 4 100574 107970 36.20 -0.26 125 -0.03 345 0.02 528 0.23 sorbose PTS gene cluster 6 192032 215092 32.62 -1.18 169 0.72 393 0.40 625 1.09 transposon-related genomic island 7 257275 268245 40.31 0.79 132 0.09 404 0.48 506 0.04 sugar metabolism (rmp) and transport gene cluster 9 549702 565259 34.69 -0.65 124 -0.05 341 -0.02 505 0.03 virulence or fitness-related genomic island 10 1001210 1005248 33.24 -1.02 163 0.62 291 -0.41 517 0.13 acid tolerance gene cluster 11 1192562 1202655 40.78 0.91 100 -0.47 333 -0.08 565 0.56 histidine metabolism (his) gene cluster 12 1252687 1308700 33.97 -0.83 149 0.38 428 0.67 580 0.69 bacitracin synthesis (bac) gene cluster 15 1781143 1794754 37.19 -0.01 167 0.69 449 0.84 592 0.80 bacteriocin-related genomic island 16 976544 982531 35.39 -0.47 126 -0.02 427 0.67 587 0.75 uncharacterized island with mobile elements

Total Records: 11