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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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 ...
7
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1answer
134 views

PDB Mining: Why Do I Find Atoms Less than 1 Angstrom Apart?

I am attempting to find potential Hydrogen bonds between Hydrogen donors and aromatic ring acceptors. I do this by predicting the location of Hydrogens on residues and then calculating how far these ...
7
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225 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 ...
7
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1answer
309 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 ...
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260 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 ...
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3answers
771 views

How exactly are game theoretical evolutionary models described during implementation for computer simulations?

When a biologist or a layman tries to reason the evolutionary explanation for something, they would simply use English with some math thrown in (for a random example, pick any explanation out of "The ...
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392 views

What's the use of DNA sequencing results?

Suppose I sequence DNA of some organism (a human perhaphs) and now I have the entire DNA "string" - the sequence of nucleotides. What's the use of that? It's just a "string" where nucleotides encode ...
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7k 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 ...
6
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554 views

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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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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122 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
304 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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115 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
226 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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1answer
42 views

What is a positive epitope fragment

What is a positive epitope fragment? I found one paper on the subject: COBEpro: a novel system for predicting continuous B-cell epitopes by Michael J. Sweredoski and Pierre Baldi
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2answers
108 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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418 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?
6
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1answer
183 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
177 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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98 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 ...
6
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270 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
886 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 ...
5
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3answers
212 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 ...
5
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2answers
188 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
76 views

The meaning of RNA-seq data

many papers I read mentioned "RNA-seq data". While searching for the meaning of this word, I could not find any layman's definition. As far as I understand, RNA-seq data is the complete RNA ...
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2answers
245 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
187 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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135 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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91 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 ...
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2answers
144 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 ...
5
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2answers
233 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
175 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
153 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
217 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
262 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 ...
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1answer
100 views

Determining if a Protein Model Contains a Backbone Clash

I have an ensemble of homology models of a protein, and I now wish to remove those models which have backbone clashes. I could obviously check by eye but this is subjective and probably will not be ...
5
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1answer
87 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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3answers
360 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
504 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
114 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 ...
5
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1answer
52 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 ...
4
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3answers
106 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
179 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
382 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 ...
4
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3answers
191 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 ...
4
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2answers
151 views

explanation of meaning of high-throughput

Almost all of the papers about bioinformatics, I faced with the high-throughput word, but I could not find any explanation about it (I think it is so easy to understand and thats why anyone explains ...
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2answers
51 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 ...
4
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2answers
119 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
149 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 ...
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4answers
272 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 ...