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 is Mendelian Randomization, and how is it used to infer causality in epidemiology?

Studies of human traits and diseases are inherently confined to observational studies, known as epidemiological studies. This can make it very hard to determine what actually causes a particular ...
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1answer
90 views

Is there a tool to find the action of an enzyme in a metabolic pathway?

Is there any tool to search the biochemical action of a particular enzyme in a metabolic pathway of an organism? In other words, how can I find if enzyme "E" is involved in the metabolic pathway for ...
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2answers
116 views

Examples of references for mathematical approaches in bioinformatics that are applicable to linguistics?

Do you have any classic references for mathematical approaches in bioinformatics that are applicable to linguistics (or vice versa)? EDIT I am mainly interested in approaches to reconstruct the ...
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3answers
285 views

Compressing structural information in PDB files

There seems to be a lot of redundancy in PDB files. These files can of course be compressed with general-purpose compression programs like gzip, but I can't help but imagine that these tools are ...
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2answers
112 views

phylogenetic analysis of gene enrichment?

Are there any tools to do phylogenetic analysis of gene enrichment? This is, I have a list of genes from an experiment performed in several species, with a z-score that can be described as ...
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2answers
219 views

Can I compare Shannon indices of metagenome gene data?

I'm comparing 12 Metagenomes. I'm using HMM counts of a number of proteins known to exists as groups within certain operons. I have grouped the HMM counts for each type of operon and calculated the ...
6
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303 views

Has any large-scale origin-of-life simulation/experiment been done?

I have been thinking a little about the origins of life, and was further inspired by this question: How did the first self replicating organism come into existence? I can accept that we don't quite ...
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2answers
201 views

Can forensic DNA analysis be used to generate a visual approximation of a suspect?

In light of the current US supreme court case, I'm curious if enough information can be teased out of a DNA sample to get a "reasonable" approximation of the suspect (never mind the legality). I ...
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2answers
107 views

How are Genetic Circuits Modelled?

I've read a recent Nature Methods paper by Moon T.S. et al, in which a synthetic genetic circuit consisting of layered logic gates was created. For example, the paper, a circuit is modelled in Figure ...
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375 views

How can I predict DNA binding affinities from a protein sequence?

Are there any computational tools to predict the binding affinity to specific DNA motifs from protein domain sequence information?
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148 views

Find protein homologs with BLASTp

I'm trying to find homologs of a set of proteins using BLASTp. I'm working with custom databases. I'm using evalue of 0.00001 as threshold. I would like to filter queries having hits with >90% ...
6
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1answer
137 views

How can promoter binding sites be determined?

I have been trying to find out which sigma factor is responsible for the transcription of RNA polymerase subunits $\alpha$ (rpoA) and $\beta ^{\prime}$ (rpoC) in Bacillus subtilis. I would expect it ...
6
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1answer
246 views

Models of quorum sensing for multi-agent systems

Quorum sensing is a system of stimulus and responses correlated to population density that is used by bacteria to coordinate gene-expression. I am looking for a simple computational/mathematical model ...
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3answers
808 views

What percentage of protein isoforms have different functions?

I am looking for studies on how many protein isoforms have different functions, preferably in human. We know that a great many, if not most, of human genes are alternatively spliced and that many ...
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171 views

Additive genetic variance components from LMER in R

I've set up some dummy data in R which makes 40 genetically related lines, they are all siblings within a line so are genetically related by a factor of ½ thus additive genetic variance should be ...
5
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3answers
195 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 ...
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2answers
179 views

First pass protein structure prediction

I'm working with a protein that doesn't have any homology to other proteins so it will likely require ab initio structure prediction. However, since I don't work for a structure prediction lab and I ...
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2answers
172 views

How can I text-mine full-text articles from PubMed?

I want to do a text mining study using full-text versions of articles I find on PubMed. My intended search protocol will be roughly as follows: Search PubMed using a gene name (and any alternate ...
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3answers
178 views

How easy is it to carry out de novo sequence assembly?

Today a colleague of mine asked the following question: " Assuming I need to build from 0, a chromosome of a fish, with short reads but no other reference whatsoever [de novo assembly]: ...
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3answers
129 views

Finding a template/oligo combination for my first PCR experiment

I'm an information technology engineer. I love biology so I research biological topics and have an interest in PCR. That's why I have decided to create a PCR machine. Everything is done now and I ...
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2answers
87 views

What is the state of automated quantitative analysis?

Quantitative analysis of microscope images is essential for many types of studies, but the techniques used most often are very labor-intensive. I have been able to find some literature about using ...
5
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2answers
192 views

introduction to Chip Seq

I hope this question is suitable for this site. I am concerned about the Chip experiment part so I think it should be okay. I am a Applied Math student starting to get into bioinformatics and so I've ...
5
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1answer
160 views

Definitions and examples of some math-releated ecology branches

I would like to have an example of application and a brief description/definition (two or three lines) of the following fields. I would like to understand the exact differences between them. Other ...
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5answers
144 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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2answers
183 views

How to get smallest subtree containing a set of nodes from BioPhylo?

I'm testing out various phylogenetic libraries in Python. I want to read in a Newick tree, then, given a list of taxa, generate the smallest tree that contains them all. This task is quite simple and ...
5
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1answer
232 views

Which way to run BLAST?

I have a set of scaffolds from a genome assembly, and I want to align a collection of proteins from various species to it. I can do this using BLAST in two ways: Create a BLAST database of the ...
5
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1answer
82 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 ...
5
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1answer
90 views

Book suggestion on computational molecular evolution

I'm currently reading Computational Molecular Evolution by Yang. Can you recommend alternative books? I am finding it to be lacking on conceptual discussion (it's more focussed on the mathematics and ...
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305 views

Tool for nucleotide alignment with all nucleotide codes (e.g. R, Y, W, S, etc.)?

I have a vector sequence and would like to find the following nucleotide sequence in it. AASYWSRA This query sequence uses several degenerate symbols, defined ...
5
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1answer
447 views

Primer Dimer / Hairpin Algorithms

What are the algorithms / methods in use for the calculation of primer dimers and hairpins? As an example, IDT's OligoAnalyzer tool will generate these analysis given particular sequences. The ...
5
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1answer
110 views

How do I prepare a PDB for submission to the Protein Data Bank?

I have a couple structures that are nearly ready to be deposited in the PDB. Out of curiosity, I ran them through the ADIT's precheck tool and they failed with one error after another, as I lacked ...
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3answers
104 views

How to create a collection of anonymous sequences for teaching and testing? [closed]

I am looking for a large collection (>1000) of sequence files (eg. FASTA) from any real organism or a tool to create such a collection. The sequence files would be used for teaching and for testing ...
4
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3answers
161 views

Why do we need deep sequencing?

Why do we need deep sequencing? Why cannot the sequencing technologies read all the nucleotides correctly at the first read? Sorry since this question is too trivial, I don't have a biological ...
4
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2answers
307 views

Why is assembling paired end illumina without any input parameters an important problem?

In one of the comments in this question about multiple sequence alignment, it was stated @5heikki: btw if you want a good bioinformatics problem, come up with an assembler that assembles any ...
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3answers
138 views

Does anyone know a good software for producing tanglegrams?

I'm trying to look at relationships between parasite and host phylogenetic trees. I have done a bit of searching for a software in which to do this with, and I have tried using Dendroscope and ...
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2answers
42 views

where to find the relative frequency distribution of synonymous codons

Most amino acids can be encoded by more than one codon. For example, Serine can be encoded by any one of ...
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2answers
94 views

positive and negative feedback

I want to know more about positive feedback in gene regulation and to know the similarity and differences between positive and negative feedbacks.
4
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2answers
119 views

How can I fetch nucleotide sequences based on ENA accession numbers and positions?

I have a list of ENA accession numbers and a start and end position in each sequence. In the end I want to align all those sequences, but first I have to fetch them and the list is too long to do that ...
4
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4answers
227 views

Is there a PSI-BLAST for nucleotide sequences?

I understand that one can translate a nucleotide sequence and run PSI-BLAST on the protein (proteins if you take the 6 reading frames), but I'm looking for distant homology for bacterial small RNAs ...
4
votes
1answer
130 views

What is benjamini

I was doing some gene expression analysis using this tool http://david.abcc.ncifcrf.gov/summary.jsp. However, I have a confusion about what benjamini is. I fed it some gene list and it gave me some ...
4
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2answers
61 views

Main methods used to predict functional annotations in GO

Can someone provide me some information about the main method used to predict the inferred electronic annotations in Gene Ontology?
4
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4answers
745 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 ...
4
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2answers
345 views

Could be an union/synergy between Math, Computer Science and Marine Biology?

I'm studing for my bachelor's degree in Natural Science and I have to chose the path for my future life. I have to chose the right kind of graduate studies. Since I love computer science, maths and ...
4
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4answers
1k views

Multiple sequence alignment - how to align everything to 1 gene sequence?

I'm having trouble aligning 3 sequences together - the total gene (~2500bp) and the forward and reverse sequences that are ~1000bp in length. Now I'm using Clustal X2, but the problem is that the ...
4
votes
1answer
90 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 ...
4
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2answers
103 views

GO terms for non-model organisms

I have a list of differentially expressed genes from an RNA-Seq experiment in Xenopus laevis that I'm looking to functionally annotate with GO-terms. As X.laevis is not listed in DAVID it seems I have ...
4
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1answer
899 views

What does conditional analysis of a SNP in a GWA study entail?

I am familiar with the use of tag-SNPs in genome-wide association studies to identify gene loci involved in complex traits, but I keep seeing the term "conditional analysis" used without any ...
4
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2answers
190 views

Confusion related to gene expression

I have a set of gene expression data downloaded from http://www.ncbi.nlm.nih.gov/geo. I have two sets of data, one is the raw probe intensity data set in the form of CEL files. Another is processed ...
4
votes
1answer
108 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 ...
4
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1answer
49 views

RNA-seq Data on domestic animal with different environment

I want to find the RNAseq data available on domestic animals in different environments. If microarray data is available, it would be more useful. If you know I would appreciate to inform me.