@techreport{TR-IC-98-37, number = {IC-98-37}, author = {Nalvo Franco de {Almeida Jr.} and João Carlos Setubal}, title = {Um {Modelo} {Oculto} de {Markov} para Encontrar Promotores em Seqüências de {DNA}}, month = {October}, year = {1998}, institution = {Institute of Computing, University of Campinas}, note = {In Portuguese, 12 pages. \par\selectlanguage{english}\textbf{Abstract} We present a Hidden Markov Model (HMM) to find binding sites, like promoters, in a DNA sequence. This approach allows variable-length spacers between the consensus sequences. The model was built using 150 known promoters of the {\em Escherichia coli} genome and uses the Expectation-Maximization (EM) algorithm to reestimate parameters. In order to test the model, we used 30 regions of {\em E.~coli}, each one known to contain a promoter. By cutting randomly these regions, we produced 20 sets of 30 sequences. The model was able to determine the correct or nearly correct (within 6 bp) 78$\%$ of the consensus sequences of a set, on average. The program is available through the WWW and can be useful as a tool to find a promoter in any procaryotic DNA sequence. } }