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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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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55 views

Expected dS/dN ratio for exome

I am trying to determine whether or not my sequencing data has more/less non-synonymous mutations than would be expected. My understanding is that there is some fixed ds/dn ratio for the human exome ...
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90 views

How can I generate a random DNA sequence?

I've found this paper which involves the construction of 19-bp random DNA sequences, but I don't know enough biology to understand how this method works. Could someone explain it to someone who is ...
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70 views

Prader-Willi Syndrome and Angelman Syndrome?

On the website http://www.whatisepigenetics.com/fundamentals/2/ it states that the imprint disorders Prader-Willi syndrome and Angelman syndrome, display an abnormal phenotype as a result of the ...
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44 views

Insertion of synthetic DNA sequence

If I have some synthetic DNA sequence (<=20 bp long), is there a way for me to reliably insert this sequence next to some n-bp motif? I'd like for this to be possible in humans. If so, are there ...
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32 views

Time needed for transcription of DNA [closed]

How much time would it take to complete the transcription of an average-sized human gene?
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822 views

Mitochondrial DNA and recombination

Firstly I could do with a brief description of mitochondrial DNA. How does the structure of DNA in mitochondria compare to animal DNA (for the sake of simplicity let's say human - some animals might ...
5
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1answer
122 views

How do electrons destroy DNA bonds in radiation?

Malignant tumors can be treated by radiation therapy. Most commonly it's radiotherapy with photons, or protons and so on. The common denominator for both types is that the radiation creates electrons ...
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35 views

How do cell repair mechanism ratios change as they age?

I have seen that embryonic stem cells are shown to use homologous repair for double strand breaks rather then non-homologous end joining (NHEJ). [1] I am wondering if something also happens to a ...
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1answer
123 views

Why do bacteria need messenger RNA?

Why do bacteria need mRNA? Isn't the DNA free floating without nuclear membrane so why doesn't the tRNA read the code directly off of the split DNA strands? (ofcourse after helicase splits them). ...
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1answer
38 views

Why isn't the RNA in bacteria always split up and replicating?

Isn't helicase always free floating in bacterial cells, and the DNA without a nuclear membrane and uncoiled and freefloating and so why doesn't the helicase keep breaking the double helix of DNA? ...
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Does a man contain all the genes needed to make a woman?

This question is brought on by a Sci Fi novel I am thinking about writing. The plot device involves a colonist in charge of building a population on a new planet who loses his supply of embryos and so ...
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67 views

Homework Question: Confused about figure related to cDNA and gDNA

what is the answer in blank? I think the loop structure for the top blank is an intron. I think RNA is the answer for the bottom blank, but it is cDNA, so it can't be RNA. I cannot figure out ...
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17 views

Amputation of part of the cytoplasm of the amoeba? [closed]

We ampute a part of the cytoplasm of the amoeba many times and we observe that amoeba is not divided This experience allows to deduce the cause of the division of amoeba Do that have relation with ...
3
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1answer
177 views

How to perform a DNA structural alignment in pymol

How can I "fit" two DNA structures having different nucleotide sequences in pymol? I would like to use the structure of a DNA binding protein in pdb (1h9t), which is bound to DNA in the pdb file, ...
7
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3answers
164 views

Are non-coding RNAs introns?

I am slightly confused as to what part of the genome codes for non-coding RNAs. Is it the introns? This would make sense to me as to why they are not transcribed as the introns are not transcribed. Or ...
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2answers
820 views

What is the instructional language of DNA?

DNA carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses (Wikipedia). Is it already know how ATCG's ...
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1answer
39 views

How DNA programs the first cell in womb into a human [closed]

Sorry if you see me silly. I am just a programmer happens to be curious about biology... So far I understand how DNA make protein, how cell divides, how one composed of cells->tissues-> organs. ...
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2answers
171 views

Why can't this be 1st meiotic division non-disjunction as well?

The child has gotten 2 "sick" chromosomes from his dad and 1 healthy from his mom, leaving it with trisomy 13. I can see how this can happen in the second meiotic division of the father but I can ...
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206 views

Why does size decrease across the sequence of human chromosomes?

The following graph shows a decrease in the amount of base pairs per chromosome across the sequential set of human chromosomes: Is this because chromosomes were originally numbered by their size on ...
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1answer
48 views

In DNA sequencing, is “mate pairs” synonymous with “paired ends”? If not, how do they differ?

By just looking at Roach et al's paper I get the impression that they are the same thing, and the Wikipedia URL for the former is a redirect to the latter. However, I suspect they are not exactly the ...
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1answer
79 views

Difference between PCR for linear template and a plasmid?

I believe PCR can be conducted both on a linear template and a plasmid, and I was wondering how these procedures differ in what enzymes are used, how the enzymes work on the template, primers used ...
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1answer
33 views

why dna polymerase 3 requires a primer for replication [duplicate]

Why DNA polymerase 3 needs a primer to star replication.And whats happens when there is no AUG sequence on entire DNA.
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1answer
73 views

Why do you need primers in PCR? [duplicate]

I have read that DNA polymerase requires a primer to bind to the DNA, but I am confused as to why this is the case. When DNA undergoes replication in the cell, there are no primers in the nucleus so ...
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1answer
86 views

Protocol to dilute DNA step ladder?

I need to run gels that are of not the "most" importance. So I do not want to waste alot of money on step ladder. How do I dilute DNA step ladder? Is there a general procedure, for I have tried ...
2
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1answer
6k views

How does a thymidine block halt DNA synthesis?

The best I've been able to find is that there's a feedback mechanism, but what is this feedback, and how does the mechanism work? If it's just that the concentration of thymidine is too high, why ...
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1answer
2k views

Calculating number of amino acids in mRNA

Assuming there were 20 different amino acids and less than 40 types of different tRNAs found in this alien organism. How many amino acids would be found in the translational product of a ...
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1answer
48 views

Can DNA base pairs go through each other? [closed]

Consider the simplified version of the motion one DNA base pair held together by a hydrogen bond: Use u and v to denote the displacements of the bases from their equilibrium position along the ...
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1answer
103 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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2answers
117 views

Alternatives to PCR

PCR uses cycles of heating and cooling to denature the strands, calling for special thermostable DNA polymerases. In a cell, during replication, Helicase unwinds the DNA without the requirement of ...
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1answer
31 views

How many nucleotides are there in the LMO1?

Dr Maris at CHOP has linked the cause of high-risk neuroblastoma to a common SNP in LMO1. How many nucleotides are there in the LMO1 gene?
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100 views

Are missing limbs hereditary?

So with my basic understanding of biology, DNA can change over time. Does this mean that if one (or both) parents have something major missing (like a limb), the kid will come out without a limb? ...
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88 views

What would be the shortest and optimal method of extracting human cells for PCR? Is there a colony PCR like protocol for human cells?

I am trying to devise a quick method to extract genomic DNA from human cells for a PCR. I first collected cells by centrifuging saline mouthwash (0.9% NaCl) and extracted genomic DNA using kit ...
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19 views

Base Excision Repair and Nucleotide Excision Repair

What's the difference between BER and NER? I understand that BER removes the improper base, while NER removes the nucleotide (including the base). However, in BER, don't repair enzymes then remove ...
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31 views

What is the aqueous solution for DNA immobilization?

This paper Electric-field assisted immobilization and hybridization of DNA oligomers on thin-film microchips Which is talking about how the electric field improve the DNA immobilization process. ...
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30 views

What are the reasons which make intron detection uncertain?

Intron/exon sequence detection seems to involve statistical prediction which can at best deliver a guess (until experimentally confirmed) as to where the splice site is. What are the reasons why ...
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1answer
91 views

difference in genetic instuctions between male and female [duplicate]

I'm a computer science graduate so please bear with me the following computer program : mov ecx, -1 INC ecx consist of 2 instructions (mov,inc) each working on specific data , can genetics ...
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2answers
49 views

Do eukaryote cells contain DNA that isn't part of a chromosome or located in the mitochondria?

I specify eukaryote in the title, but I'm also interested if this question isn't applicable to eukaryote cells in general but is to humans. I was reading "RNA-seq: An assessment of technical ...
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1answer
46 views

Query from a ppt slide

I came across this slide: Now I haven't understood what the last two grey colored lines mean. Can't ORFS be of any size? What is overlapping frames here?
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56 views

Does common PCR amplify genes regardless of what cells / barriers they are in?

I have some understanding of how PCR testing works. What I have always been wondering: how can we be sure that a primer reacts with the targeted gene(s) regardless of where¹ the genes are inside a ...
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1answer
33 views

Conjugated deoxyribonucleotides

I'm currently learning about using PCR techniques to make fluorescently labelled DNA probes, and the textbook mentions "conjugated deoxyribonucleotides" Can someone explain what these are? Nothing ...
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55 views

Why do some bacteria have an asymmetric replication?

Our teacher said that Bacillus subtilis has an asymmetrical replication fork. I know that this happens only in some strain of the bacteria . She asked us to find an explication for this mechanism , ...
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23 views

DNA replication: in which direction does the DNA polymerase 3 work?

In a couple of sites I have seen, it states that it reads in 3' to 5' direction (upstream) though the daughter strand is made in the 5'-3' direction. How does that work?
2
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1answer
210 views

Anomalous base pairing of nucleotide tautomers

What tautomers base pair with what bases? I know that adenine pairs with thymine and guanine pairs with cytosine normally. My question is what does the imino form of adenine base pair with? Regular ...
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63 views

Absorbed dose from a CT scan with relation to radiation accidents

I read somewhere that the average CTDIvol in CT scans at hospitals is ~40 mGy. This translates to the 'radiation intensity' at the center of the person, and can also be roughly interpreted as an ...
8
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1answer
105 views

Horizontal gene transfer from humans

It is known that some viruses embed themselves in the human genome. Is there a mechanism by which human genes can be transferred to other animals or plants by means of viruses shuttling them from ...
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29 views

Components of DNA repair and DDR

Many of the molecules involved in DNA repair, specifically Homologous Recombination, do not have clear differentiation from DNA Damage Response Pathway. What is the best journal article that makes ...
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40 views

Are there any arguments against the Onion Test

Are there are any sound arguments (that are simply explained) against the Onion test (http://www.genomicron.evolverzone.com/2007/04/onion-test/)? Which in turn could contribute to the argument that ...
2
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3answers
481 views

What is the biological significance of finding palindromes in DNA sequence?

I found a function called palindromes in Matlab that finds palindromes from DNA sequence. Now what is the biological intention behind incorporating this function? What the biological significance of ...
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1answer
53 views

tandem repeat sequence; causes of contraction and/or expansion question

Question: Which of the following events, occurring within a tandem repeat sequence, will cause an expansion or contraction of the array? A) Endoduplication B) homologous recombination C) ...