Deoxyribonucleic acid (DNA) is the carrier of genetic information, including for all known living organisms. The only known exceptions are RNA viruses.

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Do thymine and uracil ever appear in the same strand of RNA?

Wikipedia says that "in RNA, thymine is replaced with uracil in most cases." I'm curious what are the cases when this does not happen? Does this ever occur in normal functioning, or is it an error? ...
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232 views

Is there a DNA test to identify dog mixes?

We adopted a dog at the age of two. Our vet said it was a mix of an Australian Shepherd and Border Collie, which we've told everyone. Based on markings, I think it's likely. I am wondering, however, ...
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505 views

How to find Exons in mRNA Computationally

I'm having trouble finding a method to find exons in the original DNA sequence used to create the mRNA, even given the sequence of the mRNA, as I cannot find a way to reliably identify the beginning ...
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2k views

What is the fiber axis in the Watson and Crick paper?

I was reading Watson and Crick's article on DNA structure, and the diagram on the lower left of the first page had something called the fiber axis going through the DNA. This axis isn't in modern ...
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684 views

Does the genetic material the sperm carries affect its physical properties

Basically, what I'm asking is, is the actual sperm cell built from the blueprint in the DNA of the man or is it itself also a consequence of the DNA it carries? I'd like to know a few more things ...
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544 views

What is the minimum length required for a circular DNA ligation?

What is the minimum length of a DNA molecule for the ends to come in close enough contact that they can ligate. Assume there are free divalent cations in solution. Does anyone have any idea?
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196 views

Is DNA replaced after organ donation?

If an organ from person A is transplanted to a new human body B, is it possible that we can detect A's DNA in B? How long until the organ's DNA is replaced by B's DNA so that we are no longer able to ...
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701 views

What does it mean to “map the human genome”

I know some elementary chemistry and biology. I also think I know what a gene is (it's a sequence of DNA which encodes a particular protein). I also know that on a chromosome there are sections of DNA ...
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235 views

How are DNA polymerase error rates measured?

It is well known that the first DNA polymerase, Taq, is quite error prone. Newer generation commercial enzymes that have either been isolated from different thermophile species or have been improved ...
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362 views

What is the benefit for cells having the ATP production regulated in mitochondria compared to being from the nucleus?

Mitochondria have their own DNA and appear to be loosely connected to the nucleus and it role. Why are the functions of mitochondria not in the nucleus? Why doesn't the nucleus control the ...
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Why is the DNA helix anti-parallel? [duplicate]

Why is it that DNA strands are running in anti-parallel fashion? Given the chemical base-pairing, they could have been parallel just as well.
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enzymes that stabilize DNA loops

As a follow-up of a previous question, I would like to know what enzymes or protein complexes have been used to manipulate DNA samples into stabilizing DNA loops. I have read that cohesin is one of ...
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248 views

Mitotic crossover happens in G1?

I was reading this article in wikipedia and came across this : It has been suggested that recombination takes place during G1, when the DNA is in its 2-strand phase, and replicated during DNA ...
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39 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
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How do mutations actually occur?

DNA replication seems so mechanical- the DNA polymerase just running along the template strand. I just don't understand how mutations can arise. When it comes to substitutions, I get that a wrong ...
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194 views

Why does nature use a 4-level system (DNA) to encode information?

First, I am not a biologist, so this question might be naive: All of our information processing and storing is based on 2-level logic, bits with 0 and 1. Now, DNA stores the information in a 4-level ...
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593 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 as:...
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How does formaldehyde cause protein-DNA crosslinking?

How does formaldehyde cause protein-DNA crosslinking? I would guess it's because the strongly polar water molecule interacts strongly with polar residues on a protein-DNA complex, and adding a less ...
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802 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 homo-...
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279 views

What is a genetic marker?

In DNA sequencing and analysis, what is a genetic marker? I've heard that microsatellites are genetic markers? Those are repetitive strands of bases such as GCAGCAGCAGCA etc. Why are they markers and ...
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435 views

Does crude oil or kerogen contain ancient DNA?

According to wikipedia by the formation of oil there are a lot of organic materials present including DNA. Is it possible that this DNA is conserved somehow for millions of years?
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340 views

Biodiversity is restricted by genome combinatorics?

Me and some friends are interested in opinions for the following: Conjecture The maximum number of species must be limited by the maximum combinatorial/permutational space that can be occupied ...
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478 views

What makes DNA helical?

Why isn't DNA like RNA; why isn't RNA like DNA, that is, helical? Why are RNA chains straight?
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283 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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Is there a term for when a detrimental gene can be positively selected for because of linkage to a very fit gene?

Let's say that some piece of DNA would be subject to extreme negative selection if it were independently inherited, but it is very closely linked to an extraordinarily fit gene, and so the complex it ...
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To what extent is the genetic code more than just a code?

It is worth specifying the exact meaning of "code" in this question. A code is a map from one space to another space with which it has no algorithmic connection. Thus representing 321 as 0x141 is not ...
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What are the major causes of mutations in DNA?

I know that point mutations can change the base sequence of a gene by altering a specific codon that codes for a particular amino acid. Are these mutations purely random events that occur when DNA is ...
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103 views

Turning publicly available genome data into proteins

I'm a computer scientist who is starting to dabble with biology. My eventual goal is to model different kinds of cells with a computer program. As of right now, I'm just trying to take some smaller ...
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117 views

Clarification on the “orientation” of chromosomal rearrangements

I need some clarifications on the concept of "orientation" in case of chromosomal rearrangements. Given a deletion event on a chromosome for example, is the resulting DNA at the breakpoint always in ...
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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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can the face of a person be accurately predicted from DNA information? [duplicate]

http://blogs.smithsonianmag.com/artscience/2013/05/creepy-or-cool-portraits-derived-from-the-dna-in-hair-and-gum-found-in-public-places/?utm_source=plus.google.com&utm_medium=socialmedia&...
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Why can't we use plasmids to add genes to ourselves?

Reading these answers I wonder, why doesn't "gene therapy" use self-contained plasmids instead of trying to splice a length into a chromosome?
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Importance of Double Helix DNA Structure

Gene expression involves transcribing only one strand of DNA molecule. So i was wondering what are some biological advantages of the double stranded DNA?
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DNA of the human body?

If our DNA determines certain patterns within the human body such as hair color and eye color, if scientists were able to "turn off" such as the gene for eye color after the pattern was established, ...
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84 views

Detecting cancer or a genetic predisposition based on DNA sequencing

I am not by any means a biologist - so go easy. What would be a method for determining whether or not a patient has cancer based only on a genomic sequence? Update Thanks for the help in revising ...
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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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Is solving cancer required in order to avoid aging?

When the telomerase enzyme is not active the telomere shortens every time the cell duplicates leading to a reproductive limit (Hayflicks limit). On one hand this is a believed reason for aging. On the ...
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Difference between CDS and cDNA

What is the difference between Coding Sequences (CDS) and cDNA? Are Coding sequences the sequences that is transcribed to mRNA and cDNA in contrast DNA obtained by reverse polymerization of matured ...
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930 views

Why is DNA double stranded and RNA single stranded? [closed]

Why is DNA present as a double helix structure and RNA as a single helix? What causes the difference between them? What are the practical physiological differences between dsDNA and ssRNA? How are the ...
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Why AZT is selective towards HIV and doesn't impair human DNA replication?

I've found this article, which is a very old one (from the time when nucleoside analogs where researched as a possible way to prevent replication of virus genetic material, before the HIV epidemics). ...
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424 views

Stability of helical strands of DNA?

The DNA molecules contain phosphate groups involved in $3'\rightarrow 5'$phosphodiester linkages. These groups, in the bonded state with deoxyribose, contain 1 negative charges ($\ce{3'-PO4^{-}-5'}$). ...
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How to safely conserve my current DNA methylation marks?

I read the Wikipedia article on DNA methylation Let's say I want to extract and then stock my current DNA methylation marks somewhere so that I can use it safely 20 years in the future for a medical ...
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58 views

What does “~mitochondrial DNA ~bp linear DNA” means?

I'm surfing NCBI website -Nucleotide- to find some examples of real DNA sequences to use in my small homework project. My question is related to the title of a DNA sequence below: Sus scrofa ...
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109 views

Bayes theorem for mutations

MEN 2A is a dominant inherited disease caused by a mutation in the RET proto-oncogene. The probability of being sick when you have the mutation of the RET proto-oncogene varies with age and is assumed ...
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108 views

Is there a DNA analogue to ribozymes? [duplicate]

If not, is it impossible for DNA to have enzymatic activity?
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What is biological dark matter?

I recently stumbled upon the Biological Dark Matter wiki page. Its pretty light on details, but it appears to be genetic material found in humans that doesn't fall into currently classifications. ...
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Can we attack viruses by attaching proteins and such to their shells?

Haven't looked into this to very long, but an initial search didn't return anything. HIV uses certain co-receptors to enter our cells. Could we flood the blood stream with specially designed ...
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In DNA repair, how is it determined which strand contains the error?

DNA replication is more accurate than transcription (or RNA replication) because mechanisms exist for proof-reading and repair of DNA, but not for RNA. Consider a segment of a DNA strand, AGTC. Its ...
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262 views

How do mutations come to be shared by all cells?

It's my understanding that various hazards can damage the DNA in our cells, causing mutations. But whenever I picture this, I see the damage being done to one of our tissues (for example, our lungs ...
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109 views

How to read this DNA inversion diagram?

In the following diagram about chromosome inversion, I don't understand: Why do we need to take the reverse complement from step 1 to 2? Isn't inversion just reversing the bases in the region? How ...