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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Why do our epiphyseal plates close up in our late teens or early twenties?

What causes our epiphyseal plates close up in our late teens or early twenties? I realize that one's genetics plays the main role in this. I assume there is a gene that controls the epiphyseal plates ...
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52 views

Are the DNA codon mappings arbitrary?

I am a Biology novice so I apologize in advance if I state anything incorrectly.... My question is, are the DNA codon mappings arbitrary? I understand that the DNA code is made up of codons which ...
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2answers
181 views

Single stranded DNA in gel electrophoresis

From http://www.nfstc.org/pdi/Subject05/pdi_s05_m01_01.htm : ... The separation medium contains a denaturant in order that the electrophoresis is conducted on single-stranded DNA fragments. ...
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48 views

Activity of DNA glycosylase

I am wondering how DNA glycosylase works from the chemical point of view. Sometimes in papers I can see that they are doing activity assays with 1M NaOH and I am trying to understand why using 1M NaOH ...
2
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255 views

How is the transcription direction of RNA polymerase determined?

When transcription factors attach to the DNA strand - How do they know in which direction they have to initialize the transcription by rna polymerase? Is it always read in the same direction anyway? ...
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65 views

Can protein precipitate out in alcohol during DNA extraction?

In common lab sessions to extract DNA from strawberry or cheek cells, will there be protein contaminating the DNA extract in alcohol? If so, how can we prevent protein from precipitating out of the ...
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2answers
44 views

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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84 views

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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584 views

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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3answers
88 views

Simulating Cell differentiation

I'm a computer programmer deeply interested in Biology. I wish to write a computer simulation for cell differentiation. I understand there will be seemingly impossible challenges in doing this. But ...
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27 views

Transcription rate expressed in microarray per hour

This article gives measurement of transcription rate and the unit they're using is microarray per hour. For example, at 27°C the average expression of their genes is 236.1 microarray per hour (page ...
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34 views

What is the biding site code recognized by the parts of the spliceosome

Another question about another Youtube video. At 0:50, the splicing process begins to remove the non-coding section of the DNA (intron), so the different parts of the spliceosome attach to the borders ...
2
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44 views

Why does the stability of YAC increase with size?

From Lehninger Principles of Biochemistry : The stability of YAC increases with size (up to a limit). Those with inserts of less than 100000 are gradually lost during mitosis. Why does this ...
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24 views

Size of DNA in phage

I have read that DNA(after recombination) is packaged in bacteriophages lambda only if it's between 40000 and 53000 bp long. This constraint can be used to ensure packaging of recombinant DNA. I ...
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43 views

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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2answers
103 views

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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2answers
185 views

How much natural genetic variation is there between bacteria of the same species?

There are lots of questions about how and why there is genetic variation between organisms of the same species, but I haven't been able to find a numerical value for the expected amount of genetic ...
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485 views

What is Luc Montagnier's research on electromagnetic signals from DNA about?

After reading a Youtube comment, I started reading on Luc Montagnier's research on electromagnetic signals from DNA. I haven't been able to find a source that would clearly explain what it's about. I ...
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161 views

How does electroporation mediated recombination work?

For yeast and other organisms, DNA can be readily taken up into the cell naturally or through membrane disruption. What does applying a voltage to cells do exactly that allows more recombination to ...
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1answer
712 views

Difference between viral and human genetic material

I have heard that there is a difference between viral and human genetic material. What is that difference? If I take my cells and take DNA out of them and insert only a small part of it having a ...
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2answers
385 views

Transcription factor binding site located in intron

I have noticed that some TF binding sites are located in the introns of the genes. I am puzzled about whether the TF only binds to DNA in the initiation stage of transcription and will detach during ...
2
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1answer
79 views

What causes skewed ladder bands on an agarose gel?

I frequently ran into an issue where the bands of my ladder become skewed. What causes this? Here's an example: 0.7% agarose gel, 100V, 60 minutes. Same problem occurs with 1%. I loaded 10 ul of a 20 ...
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332 views

Properties of Satellite Chromosomes

I have some questions regarding Satellite chromsomes which could not be resolved by a google search. Does the satellite consist of telomeric sequences ? If not, What is the function of a satellite ? ...
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1answer
54 views

Converting Ensembl Compara gene tree DNA alignment to corresponding amino acid alignment

I have Ensembl compara gene tree alignments (Compara.gene_trees.57.fasta.gz downloaded from ftp://ftp.ensembl.org/pub/release-57/emf/ensembl-compara/homologies/) in nucleotide format. According to ...
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53 views

How does DNA resolve on size exclusion resin?

We generally have a good idea of how DNA separates using agarose gel electrophoresis, how well does DNA resolve on a SEC resin like superose? I get the impression that salt influences where it elutes. ...
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61 views

Maintaining purebred pedigrees and how to lessen chance of getting disease?

Many breeds of dogs are known for a high incidence of genetic disorders. German shepherd and Saint Bernard dogs are predisposed to developing a crippling condition called hip dysplasia. Q: What ...
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111 views

Should the length of the electrodes in the electrophoresis chamber be proportional to chamber's size?

I am trying to build a small horizontal electrophoresis chamber from scratch. I want to use it for comet assay and I will be using only 1 slide, so it's going to be about 3cm wide, 10cm long and 4cm ...
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59 views

How correlated are proximally related CpG sites in human DNA?

Cytosine residues in DNA that can be methylated (i.e. CpG sites) are likely to be in the same methylation state if they are geographically (proximally) close together. I can only find one paper that ...
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130 views

DIY extraction and long term storage of human DNA sample?

What is the recommended DIY way of extracting and long term storing of human DNA samples to store at home and send for sequencing in years time? Considerations: Sample material: cheek swab, hair, ...
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306 views

DNA replication Okazaki fragments

I understand multiple origin bubbles; DNA polymerase only synthesizes DNA from 5' to 3' and all that. But what I don't understand is why it has to be in fragments. Yes, DNA is anti parallel, and so ...
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3k 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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199 views

How to learn DNA Origami

Can you tell me is there any good softwares and tutorials which can be used to learn DNA Origami. I am new to this and want to learn from basics. Advance thanks for your help edited: INSILICO
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Nucleosome wrapping direction

Does anyone know which direction the nucleosomes are wrapped? I wonder: Relative to the B-DNA double helix twist direction (right-hand) Relative to the neighbor nucleosomes. Do they alternate to ...
2
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1answer
56 views

What percentage of DNA do people share?

If you picked two people in the world at random, sequenced each of their entire genome, and compared their DNA, what would the expected percentage match be?
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48 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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What to do with a DNA sequencer? [closed]

My school is very fortunate to have a DNA sequencer, and I want to find an opportunity to learn how to use it. I'm currently taking AP Biology this year, and I hope to do an independent study in ...
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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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114 views

Would it be correct to state that any biological difference between the sexes has to be found in the Y chromosome?

If the reason Why Men Don't Listen and Women Can't Read Maps is genetic, then one of the genes in the Y chromosome is to blame and in theory could be identified. Correct or incorrect?
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458 views

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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67 views

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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85 views

Do individual (free) nucleotides base-pair with other free nucleotides?

I had a student ask me about this and my google-fu let me down. He asked if individual nucleotides (not in a nucleic acid) base-pair with their complementary nucleotides, essentially forming many ...
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63 views

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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1answer
93 views

Generating custom human DNA sequences based on traits such as eye colour?

I'm wondering if it would be possible to create software (unless some already exists, but I couldn't find any) to generate human DNA (the base pairs on the double helix) containing genes representing ...
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116 views

Do spouses begin to share genes over time?

I apologize if this hypothesis sounds strange by I was wondering if any research had been done on a phenomenon which I've seen and have corroborated with many other - the idea that over time spouses ...
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1answer
54 views

Has DNA communication/interaction at a distance been empirically demonstrated?

I recently had a discussion with a statistician in my school about memory. Among other things, he told me that it has been experimentally demonstrated that when one extracts DNA from any organism and ...
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2answers
58 views

How does high-fidelity of DNA replication depend on the formation of hydrogen bonds?

Replication has an error rate of less than 1 in 100 million. DNA polymerase forms H-bond with the H-bond acceptor atoms in the minor groove. <-- enhance fidelity here? Binding of the triphosphate ...
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1answer
76 views

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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61 views

Are there beneficial genetic mutations identified by consumer DNA genotyping?

I'm looking at services like 23andme, and see that they identify a wide variety of genetic-based risks, like predisposition to diseases, hair loss, cancer, etc. Are there a more "positive" DNA ...
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1answer
39 views

Low copy numbers of plasmids

I have a plasmid with the P15A origin which apparently has a low copy number (see here). This would explain why my purification yeilds for subsequent digestion are low (gel shows the plasmid after ...
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45 views

Conclusions from hybridization results

A double stranded DNA was denatured in a mixture that included mRNA from a gene in the segment. The mixture was then cooled to promote RNA and DNA hybridization. The following figure the results. ...