General features and properties of insertion sequence elements 1.1 IS Overview 1.2 IS History 1.3 What is an IS 1.4 ISfinder and the Growing Number of IS 1.5 IS Identification 1.6 Distribution 1.7 Major Groups are Defined by the Type of Transposase They Use 1.8 Groups with DDE Transposases 1.9 Groups with DEDD Transposases 1.10 Groups with HUH Enzymes 1.11 Groups with S-Transposases 1.12 Groups with Y-Transposases 1.13 Fuzzy Borders 1.14 tIS - IS and relatives with passenger genes 1.15 IS derivatives of Tn3 family transposons 1.16 IS related to ICE 1.17 IS91 and ISCR 1.18 Non-autonomous IS derivatives 1.19 Relationship Between IS and Eukaryotic TE 1.20 Impact of IS on Genome Evolution - The importance of time scale. 1.21 IS expansion, elimination and genome streamlining 1.22 Target Choice 1.23 Influence of transposition mechanisms on genome impact 1.24 IS and Gene Expression 1.25 IS Organization 1.26 Terminal inverted repeats 1.27 Domain structure of transposases 1.28 Direct target repeats 1.29 Control of transposition activity 1.30 Transposase expression and activity 1.31 Impinging transcription 1.32 Sequestration of translation initiation signals 1.33A Programmed translational frameshifting 1.33B Programmed Transcriptional Frameshifting 1.33C Recoding suppression of stop codons using the unusual amino acids Pyrrolysine and Selenocysteine 1.34 Translation termination 1.35 Transposase stability 1.36 Co-translational binding and multimerization 1.37 Host factors 1.38 Over expression inhibition 1.39 Reaction mechanisms 1.40 Chemistry of the DDE enzymes 1.41 Chemistry of HUH enzymes 1.42 Chemistry of DEDD enzymes 1.43 Chemistry of Serine-transposases 1.44 The casposases Acknowledgements and Sources