Reversals and transpositions are the most common kinds of genome rearrangements, which allow us to establish the divergence between individuals along evolution. When the rearrangements affect segments from the beginning or from the end of the genome, we say they are prefix or suffix rearrangements, respectively. This paper presents the first approximation algorithms for the problems of Sorting by Prefix Reversals and Suffix Reversals, Sorting by Prefix Transpositions and Suffix Transpositions and Sorting by Prefix Reversals, Prefix Transpositions, Suffix Reversals and Suffix Transpositions, all of them with factor 2. We also present the intermediary algorithms that lead us to the main results. © 2014 Springer-Verlag Berlin Heidelberg.8392 LNCS 671682Agencia Nacional de Investigacion e Innovacion (ANII),Centro Latinoamericano de Estudios en Informatica (CLEI),et al.,Google,Universidad de la Republica, CSIC,Yahoo! LabsBafna, V., Pevzner, P.A., Genome rearrangements and sorting by reversals (1993) Proceedings of the 34th Annual Symposium on Foundations of Computer Science FOCS 1993, pp. 148-157Bafna, V., Pevzner, P.A., Sorting by transpositions (1998) SIAM Journal on Discrete Mathematics, 11 (2), pp. 224-240Berman, P., Hannenhalli, S., Karpinski, M., 1.375-approximation algorithm for sorting by reversals (2002) ESA 2002. LNCS, 2461, pp. 200-210. , Möhring, R.H., Raman, R. (eds.) Springer, HeidelbergBulteau, L., Fertin, G., Rusu, I., Pancake flipping is hard (2012) MFCS 2012. LNCS, 7464, pp. 247-258. , Rovan, B., Sassone, V., Widmayer, P. (eds.) Springer, HeidelbergBulteau, L., Fertin, G., Rusu, I., Sorting by transpositions is difficult (2012) SIAM Journal on Computing, 26 (3), pp. 1148-1180Caprara, A., Sorting permutations by reversals and eulerian cycle decompositions (1999) SIAM Journal on Discrete Mathematics, 12 (1), pp. 91-110Dias, Z., Meidanis, J., Sorting by prefix transpositions (2002) SPIRE 2002. LNCS, 2476, pp. 65-76. , Laender, A.H.F., Oliveira, A.L. (eds.) Springer, HeidelbergElias, I., Hartman, T., A 1.375-approximation algorithm for sorting by transpositions (2006) IEEE/ACM Transactions on Computational Biology and Bioinformatics, 3 (4), pp. 369-379Fischer, J., Ginzinger, S.W., A 2-approximation algorithm for sorting by prefix reversals (2005) ESA 2005. LNCS, 3669, pp. 415-425. , Brodal, G.S., Leonardi, S. (eds.) Springer, HeidelbergGalvão, G.R., Dias, Z., On the performance of sorting permutations by prefix operations (2012) Proceedings of the 4th International Conference on Bioinformatics and Computational Biology (BICoB 2012), pp. 102-107. , Las Vegas, Nevada, USASharmin, M., Yeasmin, R., Hasan, M., Rahman, A., Rahman, M.S., Pancake flipping with two spatulas (2010) Electronic Notes in Discrete Mathematics, 36, pp. 231-238. , International Symposium on Combinatorial Optimization ISCO 2010