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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1answer
45 views

blastn: What substitution matrix is used?

I'm currently working aligning sequences, and I need to compute similarity between pairs of DNA 'words' of a particular length. For amino acids I am able to use the substitution matrices in Biopython ...
3
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2answers
101 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
97 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
35 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
688 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
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1answer
97 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
236 views

Software to calculate Fst from sequence data

I'm looking for a software to calculate Fst from 3 loci DNA data of individuals from a metapopulation. I don't have any prior on the population structure (have no idea of the number of subpopulations ...
3
votes
1answer
104 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
50 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 ?
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2answers
100 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
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1answer
868 views

How to check if a fastq file has single or paired end reads

I am trying to check if a fastq file has single or paired end reads. How can I achieve this with an error-proof method? I checked wikipedia and MAQ but I want to know if is there a reliable document ...
3
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1answer
188 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
210 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 ...
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2answers
92 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
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2answers
180 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
votes
1answer
102 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
votes
1answer
116 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
64 views

Why are fifth order Markov Models, the ones most often used for gene prediction?

As far as we know that smallest polypeptide chain length is 60 amino acids - so if we found an Open Reading Frame (ORF) of about 60 codons without the interruption of stop codon we can consider it to ...
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0answers
60 views

How can I find the mRNA sequence for a specific prokaryotic gene?

What I want to find out is the start of the transcription for a specific gene, how long the UTR is before the actual coding sequence starts. I've looked at various databases like NCBI Gene, Refseq or ...
3
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0answers
45 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 ...
3
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0answers
130 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: ...
3
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0answers
44 views

What does the term 'epitope mapping' mean? [closed]

Epitope mapping means identifying the binding site of antibodies on the target antigen. This means that the site to be identified is part of the antigen and not antibody, am I right?
3
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0answers
228 views

Accuracy of genome size estimation by flow cytometry

I'm working on a genome project and using an in silico k-mer analysis to estimate the size of our genome based on the available Illumina reads. The k-mer based estimate is consistent across a wide ...
3
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0answers
136 views

Good poly-A filtering rules or tools

I am aligning a large number of ESTs. It seems poly-A tails show in many different ways. In addition to occurring at the very end, they can be flanked by the cloning sequence one one end, or have ...
2
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6answers
150 views

Which information can be obtained from a list of gene names?

Lets say I only have a list of gene names. I know they are up regulated and I know they are related to cancer. What information can I obtain from having only the names of genes? For example is there ...
2
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3answers
189 views

fastq-dump using mkfifo to stream data

So, fastq-dump has the ability to be run on just an SRA file accession number, such that the SRA is converted to FASTQ on-the-fly, and the SRA doesn't have to be written to disk. I'm curious whether ...
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2answers
81 views

peptide MHC microarray

"The recent technology is peptide–MHC microarray or artificial antigen-presenting chip. In this technique, recombinant peptide–MHC complexes and co-stimulatory molecules are immobilized on a ...
2
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2answers
101 views

Consensus codon optimization by organism

Does a public database exist that contains this information? I'm trying to make a simple gene annotation program that will let me input a DNA sequence and then optimize it based on one of these tables ...
2
votes
1answer
272 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: ...
2
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2answers
64 views

Simulating Drug Entry in Protein and binding?

Is there any simulation protocol or paper which can simulate the dynamics of drug entry and interaction with the target protein?
2
votes
1answer
274 views

Plastid and mitochondria

I am not biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is difference between plastid, chloroplast and mitochondria? Are there any plant ...
2
votes
1answer
109 views

How to build S16 rRNAs phylogenetic trees?

Here is what I know so far: Multiple copies are present in prokaryotes, but according to a paper by Lukjancenko el al.[1] it is enough to select the most similar ones. There are stem regions in the ...
2
votes
1answer
39 views

In DNA sequencing, is “mate pairs” synonymous with “paired ends”? If not, how do they differ?

By just looking at Roach et al's paper I get the impression that they are the same thing, and the Wikipedia URL for the former is a redirect to the latter. However, I suspect they are not exactly the ...
2
votes
3answers
275 views

What is the biological significance of finding palindromes in DNA sequence?

I found a function called palindromes in Matlab that finds palindromes from DNA sequence. Now what is the biological intention behind incorporating this function? What the biological significance of ...
2
votes
1answer
61 views

How do I find the number of child terms associated with a specific GO term?

I am trying to figure out how to find the number of child terms associated with a specific Gene Ontology (GO) term using QuickGO, without just counting the amount of terms in a list. For example when ...
2
votes
2answers
108 views

Can all biological processes be understood as computations and studied as such? [closed]

Can we understand a cell as an organic computational device? In that case the whole organism can be considered an ensemble of a large number of interacting computational devices? If this is the ...
2
votes
2answers
139 views

How to retrieve full gene names list and Entrez gene IDs and other annotation information from HUGO gene name list (in R or any)?

How to retrieve full gene names and Entrez gene IDs and other annotation information from HUGO gene name list (in R or any other software or language)? Is it possible vice versa: having full gene ...
2
votes
2answers
566 views

MOL2 to PDBQT conversion via OpenBabel and MGLTools removes hydrogen atoms

I am trying to convert a MOL2 file (includes partial charges and hydrogen atoms) into a PDBQT file for re-scoring in AutoDock Vina. However, both approaches that I tried don't keep the hydrogen atoms ...
2
votes
2answers
54 views

RNA secondary structure comparison

Do you know any program which can compare two and more different RNA secondary structures? I need find some (dis)similarities between lots of predicted secondary structures. And create maybe common ...
2
votes
1answer
137 views

Expanding the SETI initiative to seek intelligent data within DNA sequences?

I've recently read a couple articles dealing with long term data storage, and DNA was suggested as one of the prime candidates for long term storage of digital data additionally, there is this article ...
2
votes
2answers
83 views

In Sanger sequencing, why do we resort to cloning? Why doesn't PCR suffice?

I understand that in Sanger sequencing we can clone our fragments with the help of e.g. bacteria to make multiple copies of our fragments for further analysis. I also understand cloning can be a ...
2
votes
1answer
35 views

Why my base-quality in alignment is not perfect?

I have a fasta file with some DNA sequences. I would like to simulate next-generation sequencing reads from it. I'm doing it without any base error and mutation error. ...
2
votes
1answer
61 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 ...
2
votes
2answers
169 views

GATK workflow for Cancer

I am just starting to learn to use bioinformatics tools. My university has a limited and expensive bioinformatics team, so I'm mostly on my own except for big questions. I am planning to use GATK to ...
2
votes
2answers
795 views

How do download a list of the gene length of all genes?

I would like to get the gene length information of all the human genes. Is there a quick way to get this information? Thank you!
2
votes
2answers
1k views

TCGA gene expression data are missing matched normal

I'm trying to use the TCGA data portal to get gene expression data for cancer tissues, but I'm not sure what "Tumor matched normal" means. It is unclear to me if the values are already compared to a ...
2
votes
1answer
3k views

What does phasing mean?

What does phasing mean in genetics/informatics? I've heard that a phased file is a file that has genes separated by chromosome, but can someone give a concrete definition of what phasing actually ...
2
votes
2answers
100 views

TFBS predictions for yeast and pombe?

Are there any resources out there for TFBS (transcription factor binding site) predictions for the yeast (S. cerevisiae) and S. pombe genomes? Even if these are only de novo predictions, I would like ...
2
votes
2answers
74 views

How to build a trimeric protein structure from monomeric PDB file?

Problem: I have a PDB file, with a monomer, but I would like to show the entire structure - which is trimeric - but I don't understand how to merge/build or combine the monomeric units to its full ...
2
votes
2answers
112 views

Core Biological concepts explained to a Computer Scientist?

I am a computer scientist delving into Bioinformatics and I need to gain insight in biological phenomena. How would you explain three core concepts as: Evolution, Selection and Variation, to a ...