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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Understanding DNA supercoiling

While trying to understand DNA supercoiling, I came across these lines in the book Genetics by Ursula Goodenough : All natural DNA is superhelical. The axis of the duplex itself follows a ...
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If a gene altered causes cancer and creates a protein for cancer can the new protein be isolated in some way?

In the above title question, can the protein thats altered not be isolated (to separate out from other proteins) somehow? Is there nothing that can bind to the specific cancer proteins that will not ...
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Functioning of EDTA

I know that EDTA chelates metal ions. It weakens bacterial cell wall and inactivates the DNases. What is the reason why it can do so ? I guess it can inactivate DNases by altering the ...
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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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How many transcription factors are there?

In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow (or transcription) of genetic information from DNA to ...
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If everybody DNA is different then how blood can match even with matching blood group?

We know that everybody's DNA pattern is different in the world. Then how can ´we transfer blood from one person to another person and this person can survive ?
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Functioning of BRCA2

I know that BRCA2 interacts with RAD51 to repair DNA damage. But how exactly does it function ? What are the other proteins that interact with it ?
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How can I re-format my DNA motifs' position weight matrices?

I am working with a set of DNA motifs that are predicted as potential regulatory motifs (e.g. transcription factor binding sites). The motifs belong to several species, and I wanted to cluster these ...
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112 views

How does the telomere repeat sequence vary in Eukaryotes?

Question: How does the telomeric repeating sequence vary in non-vertebrate Eukaryotes? If you know the repeating sequence of a given species I would appreciate hearing it. Background: Telomerase is ...
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Association of shorter telomeres with heart disease

From this paper Those with shorter telomeres in blood DNA had poorer survival, attributable in part to a 3.18-fold higher mortality rate from heart disease (95% CI 1(.)36-7.45, p=0.0079), and ...
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549 views

Are all body atoms really recycled several times during a life?

I heard a point, that all (human) body atoms are recycled withing short period like few years. Recycled means "old" atoms are replaced by "new" ones during metabolism, leaving only structure ...
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100 views

How does DNA mess up

When there is an error in copying DNA (a mutation), what exactly goes wrong? If G goes with C and A goes with T, I don't see how that part can mess up. Is the idea that when the double helix is ...
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2 types of telomerases?

As telomerase works by adding new nucleotides complementary to the RNA it contains, it cannot work for the complementary strand. Say telomerase X has RNA complementary to the 5' to 3' strand it ...
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If DNA has a half life of about 500 years, how can old seeds be planted?

According to this article, DNA has a half life of 512 years Wikipedia claims that there are seeds planted as old as 31000 years Doing the basic math $100 / (2^{30000/512})$ we get that only about ...
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Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
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243 views

circularizing DNA molecules?

I have been reading about next-generation sequencing technologies that can sequence long reads. Even though the origin of my question is sequencing technologies, the question I am asking is about the ...
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248 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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How to DIY preserve pet DNA today so that it can be used in 20 years

I know that there are companies that offer a kit+storage of your pet DNA for around $2k. My question is if there is any other option for doing this yourself with a thought in mind that in 20+ years ...
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Quantitative Differences : DNA and Gene

After HGP, we are not having many databases which consist of several notepad files of ATCG.... Can we distinguish quantitatively a given A,T,C and G stretch as DNA or Gene?
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Looking for a DNA sequence

I am not a biologist. Please pardon me, if my question does not make sense. I am trying to obtain a DNA sequence for pattern analysis in Matlab. I used to generate random sequence ...
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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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How do mosquitoes maintain telomere length?

While the vast majority of eukaryotic organisms maintain their chromosome ends (telomeres) via telomerase, an enzyme system that generates short, tandem repeats on the ends of chromosomes, other ...
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How do we know that everybody's DNA fingerprint is unique?

How do we know that everybody's DNA fingerprint is unique? I know, I know, everybody's DNA is unique. But when we do DNA fingerprinting, we're looking at very specific regions of high variability. ...
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190 views

How do scientists create specific mutations?

Suppose I want to create a mutant like Antennapaedia how will I go about accomplishing it ? I know that radiation and certain chemicals are mutagenic. So do scientists subject animals to such ...
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What is the genetic distance where linkage can be ignored?

I heard several times that two SNPs, that have at least 1'000 nucleotides between them, can be seen as 'unlinked' due to frequent recombination events. I also once saw a paper showing a graph "degree ...
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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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DNA sequence from the middle of a gene

Someone gives you a short DNA sequence that comes from the middle of a gene. 5'- TCTAACTGATTAGC -3' 3'- AGATTGACTAATCG -5' From this sequence, determine the ...
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Why do we add salt when precipitating DNA?

All the DNA extraction protocols I have seen involve adding salts to the extraction buffer. What is the purpose of the salts? What happens if they aren't included?
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Do “transcription factor binding site” and “operator” mean the same thing?

Can the terms "transcription factor binding site" and "operator" be used interchangeably in all contexts when referring to a DNA sequence, e.g. regardless of a cell type, whether or not the binding ...
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Can a certain part of human dna can be replaced with other animals dna?

Human DNA consists of adenine, thymine, guanine and cytosine. Can thymine of other animal can be placed with humans thymine?
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In vitro transcription, contamination problem

I am using a RNA which is in vitro transcripted before I started my project. It turned out it is not prepared properly and has DNA contamination. Instead of perform the in vitro transcription again, ...
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Question about Autosomal Recessive Alleles

I had a homework question that I could not figure out. It states: A woman has cystic fibrosis in her family and did not want to have a child that suffered from the disease. She and her spouse ...
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416 views

Effect of single nucleotide deletion or insertion on primer annealing

How is primer annealing, and, consequently, PCR amplification affected by single nucleotide deletion or insertion inside the primer ? Imagine a primer like this: GCGTCATAAAGGGGACGTG (primer) and ...
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135 views

Real-time PCR delay in Cq due to insertion SNP in primer

I am collecting evidence, even anecdotal, how does single nucleotide deletion or insertion in primer region affect the outcome of real-time PCR. I am most interested in how much there is a delay in ...
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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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Removing a restriction site and introducing other at its place

What would you do if you want to remove an EcoRI restriction site and introduce BamHI restriction site at apprx. the same location ? One of the answers in my textbook was : To construct a DNA ...
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Telomere shortening during replication

It is widely know that each cell cycle during DNA replication some fraction of the telomeres is lost, and this phenomenon is called the end replication problem. Well this is due to the fact that the ...
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Phylogentic Footprinting Project

I'm working on performing phylogentic footprinting to figure out how many TRE sequences there are in the TWIST1 gene. (Sequence motifs). I'm trying to use ENSEMBL to gather orthologues of species in ...
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Need help distinguishing between a primary and secondary source

I am trying to figure out if the following article is a primary or secondary source. I'm leaning towards secondary but here are my cases for both. Primary: Published in a peer-reviewed ...
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What is this image?

What I understand is- I think this is picture of DNA. But why is it in this conformation ? What types of cells have this type of DNA ?
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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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DNA ligase mechanism

I am unable to understand what happens to the phosphates from ATP. What are they used for ?Charging 3' end or 5'end ?
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SNP genotyping using PCR

I read this wikipedia article on SNP genotyping and wasn't able to understand this part : In examining the results, if a genomic sample is homozygous, then the PCR products that result will be ...
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Gel electrophoresis after RNAse treatment

I do not understand how to solve this question. I know that RNAse will cut smaller pieces of RNA. The answer given is A
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Stay young by reinserting own DNA from years ago?

As far as I know, the DNA sequence becomes shorter every time a cell divides. A shorter sequence results in information loss and aging characteristics. As a countermeasure, shouldn't one stay young ...
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A basic example of the interactions of 2 or more non-identical alleles leading to an advantageous outcome for an individual organism

Could someone help me out with a basic example of the interactions of 2 or more non-identical alleles leading to an advantageous outcome for an individual organism? Based on empirical research OR on a ...
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150 views

How does “inheritance of methylation” of DNA and/or histones work?

What are the current models/ideas describing the mechanisms explaining inheritance of methylation on DNA resp. histone level? Is there evidance of this "setup" information being really ...
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DNA fingerprinting

I would like to make my own DNA fingerprint - just for fun to have my "autoportrait":). I was looking around a bit and all the commercial kits you can have are very expensive. Can you suggest me a ...
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Transposons and the net amount of DNA

The retrotransposons and certain DNA-transposons, are "jumping" sequences which may be incorporated elsewhere in the genomic DNA of an organism, through varying mechanisms. This insertion is almost ...