Bioinformatics connects life sciences and quantitative sciences, typically involving the application of software and algorithms to solve computationally intensive questions, such as those in genomics, sequence analysis, and systems biology. Questions tagged Bioinformatics should have a direct ...

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What makes a DNA sequence motif a DNA sequence motif?

I've read about DNA sequence motifs, but still don't understand what makes some sequence a DNA sequence motif. Is this a well-defined concept? For, example, What are DNA sequence motifs? says: ...
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2answers
102 views

Combining gene expression data from two species

I currently have two sets of gene expression data. The first is a dataframe of genes identified by Annotation id CG numbers (for example "CG10005") in one column and a numerical variable of interest ...
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98 views

Assembly of metagenomic data

I'm trying to assemble metagenomic data that comes from termite guts. The sequences comes from SOLiD and no paired, so the reads are extremely short (25bp). I have tried multiple assemblers (CLC, ...
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55 views

Where can I find histograms and tables of prevalence of mutations in cancer?

At some point in the past I found a cancer portal site which had aggregated data for the relationships between various mutations and their prevalence in cancer types and tumor data. The data was ...
4
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1answer
118 views

Online toolkit that provides functional similarity scores (in the form of a matrix) between two functional gene sets in the context of gene ontology

Where can I find an online toolkit that provides functional similarity scores (in the form of a matrix) between two functional gene sets in the context of gene ontology? I have tried the following: ...
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58 views

What value type would a chromosome position be in a database or form?

I wanted to create a tool for some fields like SIFT, Phenotype, etc..so for example I know Phenotype will have "Text" values or SIFT will have some determined values from a drop down list...but what ...
4
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1answer
70 views

Statistics on energy consumption breakdown per biological functions across organisms?

Are there any statistics available on how much energy organisms use for each biological functions (i.e. something similar to the line of "Bacteria spend X% of energy on information processing, Y% for ...
4
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1answer
784 views

How do I view the simulated protein structure along with ligand in VMD?

I did a simulation of a protein-ligand complex, and it has stabilized after 5 ns. I have got the respective pdb files for every ns, but when I try to view in VMD (Visual Molecular Dynamics), I cannot ...
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54 views

How to find ion/water channel related genes

We now have a collection of transcripts at hand. We would like to investigate some particular ones, which are ion/water channel related. How to perform this? Could anybody point out how to find the ...
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41 views

Which sequence assemblers I can use to compare different paradigms?

I'm a high school student whose interested in bioinformatics. Therefore I chose a project which I study Sequence Assembly. My main goal is to compare different paradigms (Greedy, OLC, De Bruijn). I ...
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271 views

Statistical Coupling Analysis (SCA) to identify coevolved residues: use of ICA [closed]

We've begun to try out the SCA Matlab toolbox (latest version) downloaded from Dr. Rama Ranganathan's website, and, following the included tutorials, would like to apply it to our protein family. The ...
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2answers
182 views

Biological key file format

I am in the process of creating biological key software tool for use on android devices. I would like to know if there are any established file formats for storing biological key data. Thanks
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142 views

Organize sequence database [closed]

I recently took up the task of organizing the sequencing database for a research project. I am still quite unsure of which database type I should use for this. Some advices/recommendations would be ...
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2answers
155 views

High sequence similarity but start codon isn't methionine

I have noticed in a particular genome sequence of a prokaryote that various regions in a sequence share similarity which is high(>80%) with known proteins. However, the start is not a methionine. Is ...
3
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3answers
461 views

Bioinformatics tool for “pairwise alignment” of complementary sequences?

I'm currently working on some ribozyme binding, and I'm looking for a tool that will essentially analyze the regions of the degree of complementarity in two sequences in order to extrapolate ...
3
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1answer
76 views

What information can Uniprot give me about phosphorylated forms of proteins?

I have a list of proteins formatted like this: ...
3
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1answer
573 views

Ka/Ks (dN/dS) analysis module for Python?

From this wiki article: In genetics, the Ka/Ks ratio (or ω, dN/dS), is the ratio of the number of Nonsynonymous substitutions per non-synonymous site (Ka) to the number of synonymous ...
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2answers
425 views

JMol “calculate HBONDS”: which atom is the donor/acceptor?

JMol can be used to identify Hydrogen bonds in proteins by the script "calculate HBONDS". By outputting the state of the network, we can obtain a lisdt of H-bonds. Here's one line from an example ...
3
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42 views

Are there journals for theoretical models of protein-protein interactions?

Are there respectable scientific journals for publishing models of protein-protein interactions obtained by docking simulations? I would also discuss the biological significance of the particular mode ...
3
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2answers
76 views

Microbiome Data

How is it possible to access microbiome data like that found here? I'd like to perform analyses on similar type of data, but cannot find OTU data like that at the Human Biome Project. Thanks for any ...
3
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2answers
70 views

Sequence compression method / format

As someone working with sequencing data and sequence files I was wondering whether is there a compression method / format for sequence / read files? Of course one can use general compressors like rar ...
3
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1answer
97 views

meaning of the “reads” keyword in terms of RNA-seq or next generation sequencing

I'm an undergraduate student at computer science and currently, I'm interested in bioinformatics. Today, I've started to read a paper about clustering and classification of non-coding RNAs can be ...
3
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1answer
271 views

What do the Clustal Alignment Symbols Mean?

Occasionally I will run protein alignments on peptide families and I can never remember what the symbols mean to show degrees of identity. What do they mean?
3
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1answer
182 views

Any tool to align whole genome sequence data to another genome and give exon regions a higher mark?

I want to align WGS data from several mammals to one reference such as the human genome sequence. Since in most cases exons should be conserved and spliced in the same way and introns should vary, I ...
3
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1answer
914 views

Difference between “transcriptional activity” and “RNA expression”

I am working with a network object where the nodes are different events in molecular biology. Specifically; Catalytic activity of X, RNA expression of X, GTP-bound activity of X, Kinase activity of ...
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4answers
119 views

Identifying the origin of replication of an unannotated *E. coli* plasmid

I have attempted a few searches for a list of origins of replication for plasmids in E. coli, but I was only able to find a list of origins, but not their individual sequences. The available plasmid ...
3
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1answer
733 views

Hamming distance between two DNA strings

By definition from Wikipedia, the Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. In other words, it is the number of ...
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1answer
77 views

PSI-BLAST website algorithm parameters

http://blast.ncbi.nlm.nih.gov/Blast.cgi In this website, when I want to apply the psi-blast algorithm on a sequence, under the section of algorithm parameters , what does PSI-BLAST threshold mean? ...
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2answers
309 views

How to use Autodock just for (re)scoring

I have some protein-ligand complexed that I have been docking with some other software and just want to use Autodock to evaluate those complexes. So, basically I just want to use it as a scoring ...
3
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1answer
124 views

Should the sum of RPKMs be constant over experiments

I have cufflinks data from 18 different RNA-seq experiments. I've noticed that if the sum all the RPKM values for a particular experiment, are vastly different between experiments. How could this be? ...
3
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1answer
1k views

RNA-seq analysis - q-values in cuffdiff

I'm using cuffdiff 2.1.1 to look for differential gene expression between two conditions. Each condition has 2 biological replicates. The results I get look promising from a log fold change ...
3
votes
1answer
155 views

Can compounds be predicted from Polyketide synthases gene clusters?

I've seen a few talks on the subject. From a gene cluster, there is some decent ability to determine which domains contribute to certain functional groups in the final metabolites. It sounds like this ...
3
votes
1answer
582 views

Displaying nucleotide at a single position from RNA-seq reads in a BAM file

How do I display a single nucleotide position from reads in a BAM file? I have been looking at variation using samtools mpileup, but I want to actually just display the nucleotide at the position I am ...
3
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2answers
48 views

Deciding a reasonable threshold for copy number variation in a CNV (SNP array) TCGA dataset

Is there a methodology to select a reasonable threshold for copy number variation in a CNV (SNP array) TCGA dataset, to define when there is a significative alteration? Can I download CNV data for ...
3
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1answer
69 views

Simplified molecular-input line-entry system

This may be a bit abrupt/vague question, but I didn't know how to proceed the search to get the answer. What are the properties of a 3D biomolecule which gets ignored when a 3D biomolecule is ...
3
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1answer
34 views

Gene Sequencing and Plasmapper

Is there anything similar to this in Java (especially the circular map sequencing along with hover effect)? For information I would like to convey that I am using Plasmapper and BioJava for achieving ...
3
votes
1answer
360 views

Why is Cysteine and Tyrosine used to calculate a sequence isoelectric point?

Why are the amino acids - cysteine and tyrosine used in isoelectric point calculations for a protein sequence, yet neither of them are positively charged molecules? and are not used in net charge ...
3
votes
1answer
67 views

SEREX serological analysis of cDNA expression library

What is Serological Analysis of cDNA expression library? I went through this article:http://cancerimmunity.org/serex/introduction/ but could not really make out. Can someone please explain this to me ...
3
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1answer
48 views

I2D vs STRING for protein-protein interactions

Can someone clearly explain me the differences between STRING and I2D(Interlogous interaction database) ? What does each database do best ? Which database is better for what kinds of studies etc ?
3
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2answers
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 ...
3
votes
1answer
82 views

Regarding the NCBI FTP site

I am trying to extract information about SNP data from the FTP server of NCBI. Could someone please explain to me how the directory is organised? There are many many files and folders and I can't ...
3
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1answer
146 views

mFOLD prediction result interpretation

I am trying to predict the secondary structure of certain predicted pre-miRNAs through mFOLD which is the generally accepted technique for structure prediction in most studies. I am finding it hard to ...
3
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1answer
156 views

Biological meaning/interpretation of clustering coefficience

I have been looking for some time to find an answer to the following question. I would be grateful for any help/advice or directions. I work very frequently with large number of proteins and assess ...
3
votes
2answers
90 views

Mass Spectrometry Terminology

I began reading this paper (http://www.biomedcentral.com/1471-2105/14/56) and had a few questions about mass spectrometry terminology that I couldn't find answers to elsewhere. Consider the following ...
3
votes
2answers
162 views

Why only heterogeneous SNVs for validation using genotyping arrays?

I am trying to validate the variants I found using whole genome sequencing . The standard practice, I have seen in the two publications below were to check for the number of heterozygous SNPs called ...
3
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1answer
93 views

What is a good source for info on disease frequency distribution among age groups?

I need information on the disease frequency distribution among age groups for an Android app I'm building... Hopefully I've come to the right place. Is there a good data source for this? Like a ...
3
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1answer
114 views

Superposing DNA

I have a series of protein models with DNA docked. I now want to superpose the DNA on a reference DNA molecule and extract the translational distance applied and the rotation angle used. I can ...
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0answers
52 views

Efficient algorithm to calculate various population divergence statistics

Intro and description of the data I am simulating the evolution of very long DNA sequences. The model works well, is performant and will output data in the following kind of fasta format ...
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0answers
28 views

How can I create R8 (homopolymer repeat) filter without using illumina pipeline?

illumina instruments have built-in -or online- analysis software for variant analysis (CASAVA). This software can filter out the false positive variants near the homopolymer repeats (AAAAAAAA) and ...
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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: ...