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 Porphyromonas gingivalis 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 7178 23334 50.44 0.35 90 -0.48 302 -0.63 438 -0.17 IS-related potential island 2 128858 144301 41.63 -1.43 95 -0.39 287 -0.75 467 0.09 uncharacterized genomic island 3 148690 181052 54.92 1.26 96 -0.37 327 -0.42 525 0.60 uncharacterized genomic island 4 199227 231967 44.85 -0.78 107 -0.17 306 -0.59 391 -0.58 IS-related potential island 5 353549 375744 55.07 1.29 104 -0.22 317 -0.50 535 0.68 uncharacterized genomic island 6 727794 740913 53.73 1.02 100 -0.30 312 -0.54 543 0.75 transport-related island 7 873740 939096 43.65 -1.02 128 0.22 407 0.25 511 0.47 mobilization cluster, ISPg-related 8 1028296 1043985 48.73 0.01 93 -0.43 300 -0.64 401 -0.49 IS-related genomic island 10 1167342 1195543 50.67 0.40 112 -0.07 362 -0.13 497 0.35 mobilization cluster 11 1269665 1284563 43.85 -0.98 143 0.50 424 0.39 531 0.65 IS-related genomic island 12 1520135 1538199 40.64 -1.63 120 0.07 374 -0.03 508 0.45 mobilization cluster 13 1549857 1565564 52.85 0.84 110 -0.11 337 -0.33 575 1.04 Bacteriodes conjugative transposon-related island (tra gene cluster) 14 1578596 1597485 37.25 -2.32 105 -0.20 296 -0.68 515 0.51 IS-related genomic island 15 1758531 1796435 49.75 0.21 117 0.02 384 0.06 484 0.24 IS-related potential island 16 2005445 2010268 42.40 -1.27 146 0.56 421 0.37 567 0.96 IS-related genomic island 17 2051446 2066786 52.49 0.77 115 -0.02 392 0.13 551 0.82 hemagglutinin-related cluster 18 2101130 2111755 40.76 -1.61 117 0.02 316 -0.51 509 0.46 IS-related island 19 2214142 2221575 54.34 1.14 99 -0.31 338 -0.33 483 0.23 thiamin biosynthesis cluster 20 48074 63278 49.00 0.06 119 0.06 357 -0.17 472 0.13 IS-related potential island 21 293955 310123 47.26 -0.29 90 -0.48 303 -0.62 405 -0.46 IS-related potential island 22 500619 527524 50.83 0.43 118 0.04 339 -0.32 461 0.04 IS-related potential island 23 1319677 1340727 48.32 -0.07 114 -0.04 331 -0.38 423 -0.30 IS-related potential island 24 1398895 1432136 48.96 0.05 103 -0.24 350 -0.23 423 -0.30 IS-related potential island 25 1464183 1482407 50.64 0.39 110 -0.11 370 -0.06 501 0.39 IS-related potential island 26 1725712 1742997 50.99 0.47 88 -0.52 271 -0.88 410 -0.41 IS-related potential island 28 2275212 2284438 47.70 -0.20 106 -0.19 321 -0.47 400 -0.50 IS-related potential island 29 2299717 2324027 51.58 0.59 116 0.00 337 -0.33 477 0.18 IS-related potential island 30 2325397 2334744 52.93 0.86 68 -0.89 226 -1.26 402 -0.48 potasium uptake gene cluster

Total Records: 28