Questions tagged [bioinformatics]

The science of collecting and analyzing complex biological data such as genetic codes using informatics.

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156
votes
7answers
16k views

Does DNA have the equivalent of IF-statements, WHILE loops, or function calls? How about GOTO?

Does DNA have anything like IF-statements, GOTO-jumps, or WHILE loops? In software development, these constructs have the following functions: IF-statements: An IF statement executes the code in a ...
48
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4answers
7k views

What exactly are computers used for in DNA sequencing?

I've thoroughly read the Wikipedia article on DNA sequencing and can't get one thing. There's some hardcore chemistry involved in the process that somehow splits the DNA and then isolates its parts. ...
36
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3answers
83k views

What is the difference between local and global sequence alignments?

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 not only between software but varies from software version to version. ...
33
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1answer
4k views

I just had my genome sequenced. Can someone tell me what these different file formats are?

I just had my whole genome sequenced and now I want to play a bit with bio-informatics. However, the documentation is quite scarce on the file standards used. These are the files I have been given (...
27
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3answers
6k views

Is “computational biology” different from “bioinformatics”?

Are "computational biology" and "bioinformatics" simply different terms for the same thing or is there a real difference?
25
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1answer
2k 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 ...
23
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3answers
2k views

120-year-old gene regulation problem independently solved by a computer. How?

My Background: I'm a mathematics graduate student with a physics background. I have a very little biology knowledge and a little knowledge of machine learning and statistics. Topic: I recently ...
22
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4answers
2k views

Alternatives to NCBI BLAST during US government shutdowns?

Many molecular biologists are used to going to NCBI BLAST for quick, hassle-free BLAST searches of their genetic or protein sequences. However, during the last American government shutdown in 2013, ...
21
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4answers
859 views

Machine learning for light microscopy — problems to solve?

I would like solve some biological problems that would improve the state-of-the-art of biology or bioinformatics. In particular, I want to apply machine learning on light microscopic images. The ...
18
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1answer
19k views

What is the significance and method behind Ramachandran plots?

My PI showed a Ramachandran plot in class today with minimal explanation, but I'm interested in finding out more. I understand that the Ramachandran plot shows the relation between the omega phi and ...
17
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3answers
333 views

What is the optimal frame size for protein secondary structure prediction methods?

The whole question is What is the optimal frame size for the second and third generation protein secondary structure prediction methods? Justify your answer. I remember it has something to do with ...
17
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3answers
3k 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 (...
16
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8answers
2k views

Are there examples of encryption in nature?

There are examples of mathematics in nature such as Fibonacci number, fractals, etc. Are there examples of encrypted information? What I am looking for is a pattern that seems random on the ...
16
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2answers
427 views

How can computer predictions of protein folding be verified computationally?

Currently, there is a lot of research focused on solving the folding patterns of proteins using computers (Folding@Home, https://fold.it/portal/, etc.). The question that I have is: How do you know ...
16
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2answers
397 views

Can two protein secondary structures “overlap” in the PDB?

I have a technical question regarding the syntax in Protein Data Bank files. In the protein with PDB# 1AE9 (pdb file), there are two lines in the .pdb file: ...
15
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5answers
2k views

Why did high A+T content create problems for the Plasmodium falciparum genome project?

The main paper for the Plasmodium palciparum genome project (Gardner et al., 2002) repeatedly mentioned that the unusually high A+T content (~80%) of the genome caused problems. For example they imply ...
15
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3answers
2k views

Why reference genome is a reference?

I have heard that a reference genome such as humans is generated by randomly choosing samples from a group of donors. But why do we call the DNA sequence generated as a reference? Why should we ...
15
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2answers
654 views

Looking for a cancer drug target database to guide sequencing of patient tumor DNA

I have a question I would like to pose to the community. I have recently received access to a bench-top ion torrent DNA sequencer. Our idea is to use this machine to sequence the DNA from patient’s ...
15
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1answer
313 views

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

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 Loess and correct with ...
14
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4answers
2k views

Where can I get a file/list of the common and scientific names of species?

I am searching for an un-encoded data file with common and scientific names for example of a few hundred species or tens of thousands, where I can search the common and scientific labels of organisms.
14
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2answers
1k views

Why and how does uniprot list around 150,000 proteins in the human genome?

Using organism:"Homo sapiens (Human) [9606]" as a query in uniprot returns about 146,000 proteins. I was under the impression that there were only 20-25,000 protein ...
14
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3answers
2k views

Databases for gene regulatory network graphs?

What databases are available for gene regulatory network graphs starting from a given gene? For example, starting from p53 gene, where can I find a gene regulatory network image that can be exported ...
14
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3answers
2k views

Why do restriction enzymes tend to have an even number of bases in their recognition site?

When reading my textbook I noticed that in all examples but one from eight the recognition site was an even number of bases. I wondered if this was just a co-incidence, so I took the data from this ...
14
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4answers
753 views

Computer Virus that infects DNA?

I have watched a talk by Mikko Hypponen (CEO of the security company F-Secure) called Silicon Plague. There, roughly at minute 51 of the talk, he mentions a computer code that is supposed to be able ...
14
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2answers
839 views

When does BLAST fail to align 2 DNA sequences?

This is an assignment that had confused me for a long time. So I think you guys who study computational biology might be interested. The original question is: Find the two most similar DNA ...
14
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1answer
1k views

How do I get the current “camera position” in PyMol so I can reuse it in scripts?

I have a few protein models I want to take pictures of with various ligands bound. It would be nice if I could do it from the same "position", but the only way I can figure out to repeat the same ...
13
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1answer
945 views

Human disease and associated phenotype database?

Does anyone know of any good databases that contain symptoms for diseases and other ailments in humans? I've tried working with UMLS, but thats been impossible to work with. I've also tried working ...
12
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5answers
742 views

Introductory literature for synthetic / systems biology

I am a computer engineer (MSc in Computer Engineering) who's looking to switch into the field of synthetic / systems biology. I have a comprehensive layman's understanding of evolution, genetics, ...
12
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2answers
325 views

Is there a program that simulates biology on a molecular level?

Is there a computer program that simulates biology on a molecular level? Software that has rules that simulates the rules of molecular-biology?
12
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1answer
232 views

Systems identification in small neural network

When analyzing data from cortex, we often try to understand what each neuron does in terms of its inputs from other neurons - a specific kind of a systems identification strategy. Most current ...
12
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3answers
4k views

Are there any open plant databases (database/library/collection), containing species information and pictures?

I would like to download a plant database containing photos and species details. Do you know if there are any openly available online?
12
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2answers
437 views

Biopython - Big Discrepancy Calculating RNA melting Temperature over Literature

I experience big discrepancies when calculating melting temperature of RNA 7-mers with Biopython over values generated by a popular algorithm. I tried the nearest neighbour algorithm with RNA and ...
12
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1answer
348 views

Which is the reference 16S rRNA?

Recently, I've stumbled upon a fact, which hasn't bothered me for many years. The fact is that all universal 16S primers are written as "[FR][0-9]+" (in regex notation), that is they have a position ...
11
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5answers
620 views

What was the first piece of work in computational biology?

What was the first piece of work in computational biology? I'm ideally looking for a paper. I am not interested in works that involve data management or data analysis but work that model biological ...
11
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4answers
563 views

What can you tell about a person, having only their whole genome as information?

Well, the question is in the title, no explanation need.
11
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3answers
441 views

Source of DNA sequences

I'm working on a project where I am taking DNA sequences and translating the codons into musical notes. I have some good ideas of how to do this, I'm just not sure what sequences to work with. My case ...
11
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2answers
2k views

Scoring sequence against position weight matrix

I have a weight matrix of length 20 x 15 (amino acids x sequence positions). Each element of my weight matrix is a relative probability If I have a sequence say "AAPGTGASMHSGLLW" how would I score it ...
11
votes
3answers
697 views

Shortest strings not present in the human genome

What length are the shortest strings of DNA not present in any known person's genome, and what are they? And is there a database online by which I could find this out?
11
votes
1answer
759 views

Sequence evolution simulation tool

I'm looking for a tool to simulate sequence evolution given a specific mutation model and birth-death model. I'm aware of tools and packages like INDELible, Seq-Gen and PhyloSim, but they simulate ...
11
votes
2answers
839 views

Books on machine learning applications in Biology

I have recently engaged with a collaboration, which requires me to construct, then train an unsupervised artificial neural network (ANN). However, I have only a very coarse understanding of what ...
10
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2answers
14k views

How to convert bwa mem output to BAM format without saving SAM file

I want to go straight from bwa mem alignment to BAM format as I don't need the SAM file and it takes up too much space. How do I achieve this?
10
votes
1answer
7k 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 ...
10
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5answers
32k views

What E-value BLAST cut-off is best?

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 ...
10
votes
2answers
983 views

How many gigabases of DNA are there on earth?

The human genome is about 770 MB, the C. elegans genome is about 100 MB, the yeast S. cerevisiae is about 12 MB. Different other genomes have been sequenced: how many GB of genomic DNA we have now? ...
10
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2answers
13k views

What is the difference between sequence, reads, and contigs of genetic material?

Can someone explain the differences between sequence, reads, and contigs of genetic material such as DNA, if possible with an example? I am new to bioinformatics, and I have not found any conclusive ...
10
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3answers
516 views

How do we know if the folding@home project results are right?

Some of us are involved in the folding@home project, spending time, money, and resources. I would like to know the answer to two main questions: How do we know we fold it right? I mean, these models ...
10
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1answer
1k views

Digital Genomic Footprinting for ENCODE

I'm reading over the ENCODE Nature papers, and one of the papers referred to is "Global mapping of protein-DNA interactions in vivo by digital" by Hesselberth et al[1]. Genomic footprinting is a ...
10
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1answer
992 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 ...
10
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2answers
231 views

What role does a protein's size have on protein-protein interactions?

Protein-protein interactions are when two or more proteins bind together, possibly for some important biological function. Recently, I'm starting to look more into proteins, and in particular, ...
10
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1answer
2k views

Mass spectrometry versus western blotting for validation

I have mass spectrometry data (LC-MS/MS) from rat cortices under either drug or control treatments. The results were performed in triplicate (three pairs of rats, drug or control per pair). In ...

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