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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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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108 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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240 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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44 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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79 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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47 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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87 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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95 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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66 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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56 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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77 views

Can IVF decrease the probability of trisomy in the fetuses of older mothers?

Is trisomy mostly due to complications with fertilization? If so, does in vitro fertilization reduce the probability of trisomy for the fetuses of older mothers? If not, can zygotes be screened ...
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37 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. ...
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130 views

Codon alignment via Python? [closed]

I have pairs of coding DNA sequences which I wish to perform pairwise codon alignments via Python, I have "half completed" the process. So far.. I retrive pairs of orthologous DNA sequences from ...
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1answer
110 views

Suggestions for an experiment? [closed]

I would appreciate suggestions for my year-long AP Biology project. Such a project would consists of a standard experiment, to be done over the period of a year, so it would have >to be fairly ...
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1answer
2k views

Is episome a plasmid or a virus?

A plasmid is a small DNA molecule that is physically separate from, and can replicate independently of, chromosomal DNA within a cell. In general, in eukaryotes, episomes are closed circular DNA ...
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38 views

On which part of the DNA will the new DNA nucleotide connect? [closed]

My question is: Where will the new DNA nucleotide connect on the (part of the) DNA shown on the picture? Will it connect to the phosphate group? What does the 5' --> 3' mean? Thank you in ...
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50 views

Percentage of understood human DNA [closed]

I want to know what's the approximate percentage of understood human DNA, as in, which part does what. I'm not asking for details, just the amount. Thank you.
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55 views

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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27 views

Concentration of DNA by isopropanol

I have read that DNA can be concentrated by addition of isopropanol. What does "concentrated" mean? What does isopropanol do on a molecular level to concentrate DNA?
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16 views

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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1answer
48 views

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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68 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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48 views

Clarification of the procedures to amplify cDNA needed

The typical procedure to obtain cDNA from genomic extracted DNA is the following: RNA is extracted from desired tissue, RNA/DNA hybrid is obtained by virtue of reverse transcriptase RNA dependent DNA ...
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59 views

Why use DNA polymerase in making cDNA?

RT is capable of synthesizing a complementary dna strand ( as in HIV life cycle.) Then why is DNA pol used when cDNA (synthesizing the second strand of it ) has to be synthesized from mRNA ( For eg.to ...
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41 views

Anti-parallel DNA code operons

Coming from a software engineering standpoint, suppose I have a string of code like so: ... 5'-ATAGAC-3' ... ... 3'-TATCTG-5' ... Assume the above code is part of a larger segment. Now, reading ...
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41 views

About the quality of microsatellites

I built a script to detect microsatellites in a FASTA file. However, there are thousands of possibilities. So, my question is: what are the markers of a "good" or "useful" microsatellite? - How ...
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61 views

Does DNA influence death (e.g. by cell aging)

I know that we age because of errors in the cell replication process and these errors eventually leads to death. If we exclude environmental factors, are there any other factors that can cause these ...
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70 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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36 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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128 views

Can two denatured DNA strands reassociate?

What matter if I increase the temperature to 95°C. So double-strand DNA denatured into two ssDNA, and then I decrease the temperature to room temperature. Are they able to reassociate after ...
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28 views

Genotoxic agent and their metabolic pathway

What are the mechanics (set of biochemical reactions) allowing a given genotoxic agent to modify the mutation rate at a given spot? to induce only a given type of mutation (from Gs to Cs for ...
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67 views

Complementarity of cDNA

Strictly speaking, what is the definition of cDNA? This confuses me, since usually it is said to refer to DNA that is complementary to mRNA. Is this correct? Is it restricted to mature mRNA? I ...
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75 views

Do mitochondrial DNA have repair enzymes?

Mitochondria are considered endosymbionts originated from a prokaryote. So, do they have a DNA repair mechanism ?
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161 views

How to deduce if RNA virus infection or DNA virus infection

Is there any general rule to say this must be RNA virus infection and the other one DNA virus infection? Example of a case: 5 children develop a bright red rash on the face and turns violet after a ...
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82 views

What is the mechanism of labeling a DNA molecule with deuterated water?

I have seen a paper in which deuterated water was used to follow dividing cells. The assumption was that deuterated water will be incorporated into newly synthesized DNA molecules. Is there any direct ...
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69 views

Why can't we observe haplotypes directly?

I am completely a noob to biology and DNAs, but recently I am looking into EM-algorithm used in the case of re-constructing haplotypes from genotype data. I am just wondering what exactly in the ...
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107 views

DNA Replication

I just wanted to understand the basic steps behind the replication of the lagging strand of DNA: Have helicase unwind it first DNA Primase lays down RNA primers in fragments, called Okazaki ...
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The move from RNA to DNA and the necessity of reverse transcriptase

In this piece about giant viruses and the origin of life, in the context of the move from RNA world to DNA world, virologist Valerian Dolja states: In order to move from RNA to DNA, you need an ...
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What percentage of chimeric takes up in a cDNA library?

I get a cDNA library of species of Mollusca,and complete some of the clones with polyA tails.But when I translate them with three frames,I find there is a large percentage of sequences that cannot ...
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42 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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31 views

Cloning an extinct species - how far are we? [duplicate]

What is the state of the art regarding cloning an extinct species? I don't mean Jurassic Park stuff, but for example extinct animals for which well preserved DNA and a reasonably adequate extant ...
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About virus developement [closed]

If viruses ONLY evolve from earlier viruses was their an ancestor to all viruses? Was there on ancestor to all RNA viruses? Was there a time before multicelled organisms were virus 'ancestors' ...
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Planar circular DNA and protein

I am trying to develop a planar (two dimensional) lattice based framework to simulate ring (circular) DNA and proteins. To verify my model, I need to simulate real DNA and proteins. The base idea for ...
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condensed protocol for sequencing a portion of human DNA from buccal sample

Anyone have a short & sweet protocol for PCR amplifying a region of human DNA (chromosomal or mt, I don't care) extracted from a buccal sample: including validated primer sequences and preferred ...
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1answer
27 views

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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59 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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49 views

DNA content in seeds vs. fruit flesh

Is there a publication comparing DNA yield and / or PCR-amplifiability after extraction from fruit flesh (like apples, oranges, cherries etc) in comparison to seeds of the same fruits ? I would prefer ...
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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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39 views

How is the number of histones being related to the number of chromosomes [closed]

Please name me at least one reason. I am referring to rats and to humans, as well.