"The use of structure information to increase alignment accuracy does not aid homologue detection with profile HMMs"
Sam Griffiths-Jones ∗ and Alex Bateman
Abraços
Amanda
Re: Textos p/ aula de segunda (18/10/2010)
"Automatic Identification of individual Killer Whales"
Judith C. Brown, Paris Smaragdis and Anna Nousek-McGregor.
Caso alguém queira saber sobre o que se trata. Segue o abstract:
"Following the successful use of HMM and GMM models for classification of a set of 75 calls of northern resident killer whales into call types [Brown, J. C., and Smaragdis, P., J. Acoust. Soc. Am. 125, 221-224 (2009)], the use of these same methods has been explored for the identification of vocalizations from the same call type N2 of four individual killer whales. With an average of 20 vocalizations from each of the individuals the pairwise comparisons have an extremely high success rate of 80 to 100% and the identifications within the entire group yield around 78%."
Bom final de semana a todos.
Re: Textos p/ aula de segunda (18/10/2010)
meu texto será:
Andrieu O, Fiston AS, Anxolabéhère D, Quesneville H. Detection of transposable elements by their compositional bias. BMC Bioinformatics. 2004 Jul 13;5:94. PubMed PMID: 15251040; PubMed Central PMCID: PMC497039. http://www.ncbi.nlm.nih.gov/pubmed/15251040
Re: Textos p/ aula de segunda (18/10/2010)
O que voces mandaram são textos de UMA aplicação de HMM OU profileHMM.
Re: Textos p/ aula de segunda (18/10/2010)
acho, espero, que este texto esteja no módulo que o senhor deseja.
Hidden Markov Models in Bioinformatics
Segue o abstract:
Re: Textos p/ aula de segunda (18/10/2010)
deixa ver se eu entendi. Vc quer um texto geral sobre HMM:
E um texto sobre profile HMM que fale sobre áreas de aplicação em Bioinfo:
Background: Jumping alignments have recently been proposed as a strategy to search a given
multiple sequence alignment A against a database. Instead of comparing a database sequence S to the multiple alignment or profile as a whole, S is compared and aligned to individual sequences from A. Within this alignment, S can jump between different sequences from A, so different parts of S can be aligned to different sequences from the input multiple alignment. This approach is particularly useful for dealing with recombination events.
Results: We developed a jumping profile Hidden Markov Model (jpHMM), a probabilistic
generalization of the jumping-alignment approach. Given a partition of the aligned input sequence family into known sequence subtypes, our model can jump between states corresponding to these different subtypes, depending on which subtype is locally most similar to a database sequence. Jumps between different subtypes are indicative of intersubtype recombinations. We applied our method to a large set of genome sequences from human immunodeficiency virus (HIV) and hepatitis C virus (HCV) as well as to simulated recombined genome sequences.
Conclusion: Our results demonstrate that jumps in our jumping profile HMM often correspond
to recombination breakpoints; our approach can therefore be used to detect recombinations in
genomic sequences. The recombination breakpoints identified by jpHMM were found to be
significantly more accurate than breakpoints defined by traditional methods based on comparing single representative sequences.
É isso?
Re: Textos p/ aula de segunda (18/10/2010)
Extinguindo as baleias, segue o paper que tem uma base introdutória sobre HMM e algumas variações dessa técnica além de alguns aspectos relacionados com a bioinformática tais como:
(1)- Gene finding
(2)- Alternative splicing
(3)- Signal Analysis.
Abstract
Markov statistical methods may make it possible to develop an unsupervised learning process that can automatically identify genomic structure in prokaryotes in a comprehensive way. This approach is based on mutual information, probabilistic measures, hidden Markov models, and other purely statistical inputs. This approach also provides a uniquely common ground for comparative prokaryotic genomics. The approach is an on-going effort by its nature, as a multi-pass learning process, where each round is more informed than the last, and thereby allows a shift to the more powerful methods available for supervised learning at each iteration. It is envisaged that this "bootstrap" learning process will also be useful as a knowledge discovery tool. For such an ab initio prokaryotic gene-finder to work, however, it needs a mechanism to identify critical motif structure, such as those around the start of coding or start of transcription (and then, hopefully more).
For eukaryotes, even with better start-of-coding identification, parsing of eukaryotic coding regions by the HMM is still limited by the HMM's single gene assumption, as evidenced by the poor performance in alternatively spliced regions. To address these complications an approach is described to expand the states in a eukaryotic gene-predictor HMM, to operate with two layers of DNA parsing. This extension from the single layer gene prediction parse is indicated after preliminary analysis of the C. elegans alt-splice statistics. State profiles have made use of a novel hash-interpolating MM (hIMM) method. A new implementation for an HMM-with-Duration is also described, with far-reaching application to gene-structure identification and analysis of channelUrl: http://www.biomedcentral.com/1471-2105/7/S2/S14
Re: Textos p/ aula de segunda (18/10/2010)
Alan
Re: Textos p/ aula de segunda (18/10/2010)
Agr é:
Recent Applications of Hidden Markov Models in Computational Biology
Khar Heng Choo, Joo Chuan Tong, Louxin Zhang
Re: Textos p/ aula de segunda (18/10/2010)
Re: Textos p/ aula de segunda (18/10/2010)
Confirma para mim se esses dois paper pode ser?
Sobre HMMs:
Título: What is a hidden Markov model?
Autor: Sean R Eddy
Comentário: "Statistical models called hidden Markov models are a recurring theme in computational biology. What are hidden Markov models, and why are they so useful for so many different problems?"
Disponível em: <http://www.nature.com/nbt/journal/v22/n10/full/nbt1004-1315.html>
Sobre profile HMMs:
Título: Profile hidden Markov models
Autor: Sean R. Eddy
Resumo: The recent literature on profile hidden Markov model (profile HMM) methods and software is reviewed. Profile HMMs turn a multiple sequence alignment into a position-specific scoring system suitable for searching databases for remotely homologous sequences. Profile HMM analyses complement standard pairwise comparison methods for large-scale sequence analysis. Several software implementations and two large libraries of profile HMMs of common protein domains are available. HMM methods performed comparably to threading methods in the CASP2 structure prediction exercise.
Obrigada
Abraços
Amanda
Hidden Markov Models and their Applications in Biological Sequence
Analysis
Byung-Jun Yoon
Current Genomics, 2009, 10, 402-415
Abraços,
Fernando
HMM: Martin, 2006 - Analysis of an optimal hidden Markov model for secondary structure prediction. (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1769381/)
pHMM: Huang, 2005 - KinasePhos: a web tool for identifying protein kinase-specific phosphorylation sites. (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160232)