Terminal Inverted Repeats (TIRs) are short sequences that flank the internal regions of DNA transposons. They themselves are flanked by Target Site Duplications (TSDs).
A well-studied example of TIRs is in the bacterial transposon family Tn3 , which are particularly important due to the fact that they encode ampicillin resistance. Tn3 transposons are 4957bp in length + their TIRs are between 35-48bp long. All transposons in this family have > 90% sequence similarity.
Here is a great article explaining the difference between LTRs and Terminal Inverted Repeats (TIRs). This is also where the above image was taken from .
1. Ichikawa, H., Ikeda, K., Wishart, W.L. and Ohtsubo, E., 1987. Specific binding of transposase to terminal inverted repeats of transposable element Tn3. Proceedings of the National Academy of Sciences, 84(23), pp.8220-8224.
2. Howe, M. and Berg, D., 1989. Mobile DNA. Amer Soc Microbiol, Washington DC. [see chapter 5]
3. Llorens, C., Futami, R., Covelli, L., Dominguez-Escriba, L., Viu, J.M., Tamarit, D., Aguilar-Rodriguez, J. Vicente-Ripolles, M., Fuster, G., Bernet, G.P., Maumus, F., Munoz-Pomer, A., Sempere, J.M., LaTorre, A., Moya, A. (2011) The Gypsy Database (GyDB) of Mobile Genetic Elements: Release 2.0 Nucleic Acids Research (NARESE) 39 (suppl 1): D70-D74 doi: 10.1093/nar/gkq1061
4. Ichikawa, H., Ikeda, K., Amemura, J. and Ohtsubo, E., 1990. Two domains in the terminal inverted-repeat sequence of transposon Tn3. Gene, 86(1), pp.11-17.