A computational technique to compare two nucleotide or protein sequences. There are two basic types of sequence alignment i.e. local alignment (local comparison of subsequences) or global alignment (end to end comparison of the entire sequences).

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How do I select the sequence identity threshold in cd-hit to cluster proteins for core genome comparative analysis?

Can anyone suggest a method for selecting the sequence identity threshold for protein clustering in cd-hit? If I use too high of a threshold, then the number of protein clusters shared between three ...
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36 views

Determining the percentage of the query of an alignment from a BLAST output

Given this BLAST output, how can I determine the percentage of the query sequence in the alignment? I know that it's also referred to as 'query cover' but I can't seem to find anything online that ...
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73 views

How to get only perfect matches with blastn?

I have installed Blast locally and I've configured the nucleotide database to use. I want to search some sequences (from a .fastafile) in this genome. So I used blastn: ...
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259 views

How can I align more than 2 sequences locally?

ClustalW and Omega of EBI and Blast of NCBI, both globally align sequences. Smith waterman of EBI aligns sequences locally, but works with just two sequences. How can I align more than 2 sequences ...
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HMMSearch full output

is there a way to get a full sequence output for hmmsearch? I am running one sequence against my HMM and the result table only shows chunks. I would like to have a result for each AA in my sequence ...
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EMBOSS matcher and supermatcher - incongruent results?

I am trying to align a sequence to the mouse genome. I know a priori that part of my sequence should align to chromosome 9, but not all of it. I gathered that EMBOSS' ...
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2answers
174 views

What is the meaning of dots and dashes in clustalw?

I am converting outputs in stockholm format to clustalw using ...
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1answer
94 views

Is using Hidden Markov Models to find homologues sensible in abstract, short sequences?

HMM alignment tools like hhpred excel at finding subtle homologues of folded proteins that simpler scoring techniques (such those used in BLAST algorithms) would miss. I am only looking at a small ...
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240 views

How to do whole genome sequence alignment in R or Ruby/C++, any good language? [closed]

I need to perform tuberculosis mutation analysis. First step I need to do is to align sequences in fasta format against one reference file. i tried CLC genomics workstation --- it hangs on 60 000 ...
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88 views

Whole genome sequence analysis software

Please help to choose Bioconductor R packages and other software for the whole genome sequence data analysis and, in particlular, the goals of false discovery mutation rate, mutations exclusion, ...
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79 views

Aligning multiple sequences in heterogeneous group

I have a list of ~200 DNA sequences, representing probably 50 different genomic regions but they're all mixed up. For example, if I have seq1, seq2.... seq10, ...
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188 views

Bowtie: cannot read fasta file?

I am trying to use bowtie2 to analyze my data in FASTA format, but it seems that this version can't read properly my data. My command line is as follows: ...
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123 views

Where to find the corrected BLOSUM matrices?

I was looking at this paper which talks about the miscalculations in the BLOSUM matrices and how the "wrong" BLOSUM62 matrix performs better than the corrected version. I was trying to find the ...
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53 views

Applying Constraint Programming to sequence alignment/analysis

My Masters program is focused on formal methods such as SAT solving and constraint programming. I am interested in applying such techniques to problems in sequence alignment and sequence analysis, ...
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45 views

How is the GenBank used in typical biological research? [closed]

How is the GenBank used in typical biological research? According to the GenBank statistics, the database contains about 100 million sequences. I find it difficult to understand why is all that data ...
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1answer
116 views

Datasets of aligned nucleotide sequences [closed]

Where can I find some datasets of aligned nucleotide sequences? And what should I assume about the accuracy of the alignments there? (I would like to use such datasets for training the alignment ...
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1answer
104 views

Standard datasets for testing new multiple sequence alignment algorithms?

Are there any open and freely distributed standard datasets for testing new algorithms for multiple sequence alignment?
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181 views

What is the state-of-the-art algorithm for multiple sequence alignment?

Which algorithm or algorithms are considered the standard or state-of-the-art for multiple sequence alignment? How big is the need for better algorithms? How many sequences need to be alignment in a ...
4
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1answer
141 views

Blosum matrix with probabilities instead of the positive and negative scores

I am trying to find a version of the BLOSUM matrix that has the frequencies instead of the scaled log-odds. i.e. instead of the common version that tells us that the score LEU/ASP is -4, I would like ...
2
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1answer
73 views

Converting Ensembl Compara gene tree DNA alignment to corresponding amino acid alignment

I have Ensembl compara gene tree alignments (Compara.gene_trees.57.fasta.gz downloaded from ftp://ftp.ensembl.org/pub/release-57/emf/ensembl-compara/homologies/) in nucleotide format. According to ...
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94 views

Sequence alignment scoring

The following table is from Deonier's text Computational Gene Analysis at p. 152. This is an exercise in global sequence alignment and scoring of alternative sequences. The text proposed a solution ...
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221 views

Codon alignment via Python? [closed]

I have pairs of coding DNA sequences which I wish to perform pairwise codon alignments via Python, I have "half completed" the process. So far.. I retrive pairs of orthologous DNA sequences from ...
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2answers
107 views

what does sequences overlap indicate

what does it mean if different protein sequences overlap upon multiple alignment, are they the same, do they have a common ancestor, are they recombinants of each other and how does one go on to ...
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What is the difference between local and global sequence alignments?

Obviously there are a bunch of different alignment tools out there, and I don't want to get bogged down in the maths behind them as this differs from software version to version. I am aware that ...