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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60 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 ...
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32 views

Single channel micro arrays

What does single channel microarray mean? When is it used? Thank you for your case in advance.
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45 views

Clustal Omega - convert from distance into # of substitutions

I have a set of nucleotide sequences for which I have aligned using Clustal Omega. In particular, I performed a full alignment, and obtained a full distance matrix. The distance matrix scores range ...
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3answers
74 views

Are there tools for automatically parsing glycan names into tree structures?

My colleague and I are working on a project involving data produced at a glycan microarray facility. The array data that came back to us were a list of glycan names (in IUPAC condensed format). We ...
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42 views

Why are low throughput methods more trustable for protein interaction?

I read that protein interactions found using high throughput methods are less trustable than those found using low throughput methods. For example, searching for interaction of BRCA2 on BioGRID, I ...
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2answers
69 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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67 views

Systems Biology of triacylglycerol (TAG) synthesis in Jatropha

I need the genetic regulatory network of TAG synthesis (Kennedy pathway) of Jatropha plant?? Or is there any way to convert metabolic pathway into genetic regulatory network?
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1answer
201 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 ...
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3answers
55 views

Using PSI-BLAST

I understand that the first BLAST yields almost the same results as blastp. The second time the iterated blast generates different results as it uses different matrix based on our first result. But I ...
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1answer
51 views

Hidden Markov Model

I read about the hidden markov model in bioinformatics. I amn't able to understand what it is. Can anyone explain me in brief and in very very simple words what it is ? I have NO background in ...
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48 views

Biopython error [closed]

from Bio import SeqIO for seq_record in SeqIO.parse("ls_orchid.fasta", "fasta"): ... print(seq_record.id) File "", line 2 print(seq_record.id) ...
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1answer
109 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 ...
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1answer
202 views

basic programming and bioinformatics [closed]

As a molecular biology graduate student I have decided to learn some basic programming and bioinformatics since everybody says that it is crucial. For example, what would you learn if you need to work ...
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35 views

comparing conventional phylogenetic tree to phylogenetic trees which are based on enzymes

I built trees (for 4 organisms: mouse, human, drosophila and C-elegans) for different enzymes family, compared them to the conventional tree, and try to explain them. how would you explain these ...
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1answer
54 views

Genome Assembly Using Reads

I'm taking an online bioinformatics class and I am stuck on a problem. The resources I have found don't help that much. Here is the problem: "Assemble the error-free reads from a circular genome on ...
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3answers
85 views

Phylogenetic tree

I want to find the conventional phylogenetic tree of human, mouse, C elegans and drosophila, without all the other organisms. Do you know where can I get it? thanks, Noga
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2answers
92 views

How do you find pre-miRNAs from mature miRNA Blast output?

So in short, I did a blastn with standalone blast using all known miRNAs against the EST sequences in a genome (word length 7 and e-value 0.01). Now to confirm one of the next steps would be obtain ...
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2answers
51 views

Bioinformatics : Drawbacks of using ORA(Overlap Analysis)

What do you think are the potential drawbacks/weakness of using ORA to explain distinction between two phenotypes. I identified a few which were the dependencies of DE and the statistical method used ...
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2answers
100 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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2answers
80 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 ...
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2answers
38 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 ...
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1answer
69 views

Transcribing DNA to mRNA with introns

I have a problem in my bioinformatics class that I thought I was doing right, but someone else is getting a different answer. Here is the problem: Given the following DNA sequence, ...
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1answer
95 views

Transition/Transversion ratio

I'm taking a bioinformatics class and at this point we are just going over basic stuff about molecular biology. Half of the class is doing reading/research on our own, so there isn't much class time ...
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2answers
53 views

Connection between genes and pathways

I am reading about a paper about inferencing pathway information in cancer cells. Authors refer to ERBB2 as a gene and a pathway. I don't have solid biology background. What exactly means when we ...
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2answers
78 views

Reference sequence for defining single nucleotide polymorphisms

Single nucleotide polymorphism (SNP) or genetic variation in general, by definition are relative to a reference sequence. When we talk about databases of SNP as in ("dbSNP—Database for Single ...
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1answer
58 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 ...
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3answers
63 views

What is the datatype of dna sample?

What is the type of data you get when analyzing dna of a person? If you want to store them in a database, what type of field you will need (text,number,hex)? And what should be it's length?
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1answer
140 views

Codon alignment via Python? [closed]

I have pairs of coding DNA sequences which I wish to perform pairwise codon alignments via Python, I have "half completed" the process. So far.. I retrive pairs of orthologous DNA sequences from ...
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1answer
372 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
81 views

what does sequences overlap indicate

what does it mean if different protein sequences overlap upon multiple alignment, are they the same, do they have a common ancestor, are they recombinants of each other and how does one go on to ...
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1answer
58 views

bioinformatics /genomics [closed]

i am looking for likely truncation sites to prove recombination in sequences. i have 4 sequences. i believe one to be the "real sequence" and the other 3 to be recombinants caused by cleavage possibly ...
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3answers
168 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 ...
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167 views

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

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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3answers
168 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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1answer
48 views

Finding RNA Loops

I was rooting through the literature, but there is too much work on the topic of detecting loops in RNA and the RNA helices that go with them. Can anyone point to a good review on this topic or even ...
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3answers
145 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 ...
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2answers
209 views

Blast a sequence against multiple databases

I would like to BLASTP a list of protein sequences in fasta format against multiple protein databases. Since I'm only interested in the first hit of each database, it is possible that BLAST result ...
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1answer
21 views

How to get conservation of vaccine candidates between hundreds of bacterial strains?

We have identified vaccine candidates via an ex-vivo RNA-seq approach. Next step would be to perform conservation of these candidates (about 20) between multiple bacterial strains (about 200). I would ...
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1answer
176 views

What are the differences between HPRD and BIOGRID databases?

What are the differences between HPRD and BIOGRID protein-protein interactions databases? What are their purposes? Why do we need two different databases? How is data collected into each one? How ...
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1answer
68 views

(Web)app to search metabolic/signalling pathways

I'm looking for an application where you can find pathways by selecting a chemical occurring in it. So, for example, selecting 6-phosphogluconolactone brings up the pentose phosphate pathway or any ...
4
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1answer
142 views

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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0answers
62 views

Workflow for batch analysis of ROI in histology samples

This is a pretty big task, and I have several work-arounds, but I am looking for an efficient way to go from PAS stained slides of lung tissue to defined ROI's over the whole slide (presumably via ...
5
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1answer
145 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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0answers
66 views

At which step apply a detection filter when preprocessing microarray data? (Before/After normalization, batch effects removal)

I am trying to understand what is the best practice when preprocessing microarray data using a detection filter (on scanner p-value). Suppose I have a microarray dataset that I have to normalize with ...
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0answers
124 views

I need help plotting ADMIXTURE results in R [closed]

I am trying to plot ADMIXTURE output in R. My output is two-dimentional (two columns, 190 rows). These rows represent individuals, and groups of them (e.g., 1-12) represent populations. I have eleven ...
2
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2answers
114 views

Image analysis of GFP-tagged protein localization bursts

I'm reading an article (full text here) that analyze the dynamics of localization of a GFP-tagged transcription factor (Crz1) over the time at the single-cell level, by taking movies in a fluorescent ...
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1answer
54 views

Is the book “Bioinformatics for Geneticists” outdated?

I am going to be working with genetics data in my organization's data warehouse next year and helping our biotechnology department. I work in academic research, but I have very little genomics ...
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2answers
3k 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 ...
3
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3answers
238 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 ...
2
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1answer
77 views

.Net DNA/Codon Parser

Does anyone know of an .NET (C#,VB.NET, maybe F#) DNA parser? If not I will probably make one, it doesn't seem like it would be hard. My general idea was to generate something that would report the ...