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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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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1answer
44 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 ...
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1answer
45 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 ...
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1answer
49 views

Comparing Shine Dalgarno scores, creating a distribution

I am in the process of creating a poster for the phage that I recently annotated. The phage is an A4 and the portion of the poster I am working on is analyzing the data that we have collected. I have ...
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1answer
42 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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1answer
39 views

To what extent is it possible to understand if a bacteria can produce a protein? (in silico only!)

I have to answer a question about a sub-task of my thesis: Can the bacteria X produce the protein Y? I searched of course Google and BLAST. There is no data supporting that this specific bacteria ...
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4answers
100 views

E-value BLAST cut-off

What is the best cut-off for e-value in BLAST? Some say 0.01 ,others 0.0001? Even BLAST tutorials don't give a very clear idea about which cutoff suits which purpose? Could some experts give me a ...
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1answer
41 views

About the quality of microsatellites

I built a script to detect microsatellites in a FASTA file. However, there are thousands of possibilities. So, my question is: what are the markers of a "good" or "useful" microsatellite? - How ...
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0answers
48 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 ...
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2answers
90 views

Heterochromatin binding sites position information

I am working on a project and I'm trying to find data on the position of genes and heterochromatin binding sites such as HP1 in Drosophila melanogaster. Is this information available for the DGRP ...
2
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2answers
71 views

chimeric sequences [closed]

I understand that chimeric sequence identification is done in results of sequencing projects to remove them and improve the quality of the output. I am unsure as to how they show up during sequencing. ...
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1answer
50 views

Convert gene name to uniprot ID

i have a list of gene name in a file CHRNB2 EGR2 GCK KRT14 LMNA FGF3 TK2 ABCC8 How can I map them to uniprot ID ? P.S I tried Uniprot "ID mapping" ...
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2answers
46 views

is there a way to do batch download for all gene pathways?

I would like to download all the gene pathways and genes of each pathway. Preferably, gene length of each gene as well. It would be a lot more convenient if there is an R package.
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2answers
36 views

Hiding identical sequences in NCBI web interface

Sometimes there are identical sequences in Genbank/Genpept, most often coming from the same species but different strains. Ie if I look up "bacteria chitin synthase", the 624-aa protein from Dickeya ...
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1answer
25 views

Alleles notation in SNPPedia criteria

I can understand the allele notation when is in the form rs8176719(T;T) or rs8176719(G) but recently i found this ones rs8176719(T;-) or rs8176719(-;T). So im confused, rs8176719(T;-) is the same as ...
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1answer
70 views

Recombination-based vs. Sequence-based genetic mapping

Now that sequencing is becoming increasingly cheap, what is the value of recombination-based genetic mapping against the sequence-based genetic mapping? I think that in the past recombination-based ...
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0answers
42 views

Can a heterozygous allele show non-heterozygous expression in a family?

I'm doing a family study looking for novel cancer-associated variants in germ-line samples; the goal is to find candidate biomarkers which might be used for early detection. At an earlier step our ...
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1answer
52 views

Can someone suggest me good opencourseware links for learning computational biology basics?

My internet is slow and I have only 1GB data usage allowed for this month. And I want to make maximum out of it for learning some basics of computational biology. Which are the best online course ...
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5answers
128 views

What are some examples of evolving networks in biology?

I'm a master student working on networks analysis in general. A network is something that has nodes and there are links between the nodes. Nodes and links could have attributes. An evolving network is ...
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0answers
47 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 ...
4
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1answer
53 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 ...
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2answers
956 views

How can rooted and unrooted (phylogenetic) trees be distinguished from one another

I understand that both are similar in structure But how can they be easily identified as one or the other? Is it simply based on the presence or lack of a named root (the root is identified as a ...
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1answer
35 views

Quantitative Comparisons of Phylogenetic trees

I am working on a broad phylogenomic analysis of proteins involved in one particular cellular process. I have constructed a phylogenetic tree for each protein. I am now working on comparing those ...
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3answers
157 views

Protein structures given in PDB and SNP's

There are millions of proteins given in PDB, the sequence for which we can download in FASTA format. There are also hundreds of SNP's given in NCBI dbSNP. My question is whether the proteins in PDB ...
3
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1answer
101 views

The parameter for setting the number of mismatches in standalone blast

In a standalone blast search, is there a parameter that could be specified to fix the number of mismatches allowed in an alignment. I went through the parameters and I could only find parameters to ...
3
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1answer
50 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? ...
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0answers
24 views

dbSNP database table desciptions

I am trying to build a local implementation of dbSNP. I would like to know the descriptions of tables listed on ftp://ftp.ncbi.nlm.nih.gov/snp/database/organism_data/human_9606 and on ...
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1answer
47 views

What is the close and related genome used for in Gene models?

all I am a little bit confused about using the related genome or reference genome. When we have a reference genome, we can do alignment. Also we can do the assembly. Can you give some more reason ...
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0answers
24 views

What percentage of chimeric takes up in a cDNA library?

I get a cDNA library of species of Mollusca,and complete some of the clones with polyA tails.But when I translate them with three frames,I find there is a large percentage of sequences that cannot ...
3
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1answer
33 views

Local storage of NCBI database in MongoDB [closed]

My short term goal in a project is to build a local database of the NCBI dbSNP database. The data and schema are available on the FTP site(). I was going to implement the database using MySQL, but I ...
2
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2answers
67 views

Databases for metabolic pathways of human disease

Which databases contain the metabolic pathway of human diseases? I have searched Metacyc and KEGG but didn't find the appropriate metabolic pathway.
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0answers
24 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
35 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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1answer
28 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?
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1answer
18 views

Why are different lengths of nucleotides taken for structure prediction from an miRNA match area after BLAST analysis?

Generally in miRNA prediction most researchers do as Blast search with a set of miRNAs downloaded from miRBase with the parameters they require. Later on usually custom methods are utilized to get an ...
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0answers
29 views

Meta-Data Retrieval from Bio-Rad Images

I asked a related question on SO, but I also had some biology related questions to this issue. One of the big things I'd like to do is sort between DNA/UV images and Western/Chemi images. After ...
1
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1answer
60 views

downloading a reference genome for alignment

I am currently working through the code example on the MATLAB website. It requires me to download the reference genome of Arabidopsis thaliana (thale cress) so I can use BowTie2 to align the Chip-Seq ...
3
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1answer
48 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 ...
2
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1answer
54 views

Steps to confirm if predicted miRNA is good or bad

I aligned all miRNAs available to the supercontigs of a particular genome with certain parameters (e value of 0.01 and a word match of atleast 7 as suggested in this paper). I have also isolated the ...
7
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1answer
147 views

List of np-hard problems in biology/bioinformatics

I'm not sure if this is the right place for this but... I am looking for a list of computationally "hard" problems such that if a problem from this list could be solved effectively, it would be ...
5
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2answers
2k views

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 ...
2
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1answer
125 views

How to determine the direction of regulation of a gene by comparing gene expressions?

I am just learning about the gene expressions and regulation. Several researches focus on finding the genes of altered gene expressions on a microarray to claim that they have a correlation to a ...
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0answers
28 views

What is the suitable terminology to describe this study approach?

I need to know the correct term(s) which are usually used in the parlance of both biology and bioinformatics for this study approach: About 11 transcripts were investigated using qPCR for a number of ...
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2answers
154 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
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1answer
36 views

H O N C alternatives for organic life?

Most organic structures built from hydrogen, oxygen, nitrogen and carbon. They are represent 1-,2-,3-,4- bond relations (chemical valence) which allow to build variety of chain structures. Are there ...
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2answers
77 views

What is most simple eukaryotic genome?

Expressed in number of Base Pairs or Bytes, about how much large is the simplest eukaryotic genome? How much of this is 'junk-DNA' (non-coding)?
5
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1answer
78 views

Base Substitution Probabilities Derivation

In Felsenstein's 1981 Paper Evolutionary Trees from DNA Sequences: A Maximum Likelihood Approach, he describes (in equations (6) and (7)) a derivation of the equation of the probability of a ...
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1answer
83 views

Color van der waals bonds in swiss PdbViewer

I'm trying to color certain amino acid's van der waals bonds as in the following picture: can anybody please describe the steps to accomplish that?
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2answers
73 views

Gene perturbation, what is it used for, explain to computer scientists? [closed]

I am trying to build a gene regulation network, and I need some basic knowledge of it. So, in gene research, we perturb genes. Such as knock down them? Can people tell 2 or 3 experiment methods to ...
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3answers
125 views

What is the potential function of ultra-conserved elements in the genome?

If selection pressure results in conservation of DNA sequences, what is the most plausible explanation for the existence of ultra-conserved elements (refs here and here) given that there hasn't been ...