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Questions tagged [dna]

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 percentage of twins has the same gender

If 30% of all twins are identical twins, what percentage of twins has the same gender? I thought: all identical twins have the same gender so it’s at least 30%. And of the non-identical twins it’s ...
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DNA linking number, twist and writhe

The image below is taken from a molecular biology textbook. It is not clear to me that what is happening at the two writhe crossings matches up with the numbers provided. Is there a problem with ...
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Are there examples of cells with more than one nucleus?

I've always wondered why cells have only one nucleus, as having multiple would seemingly prevent mutation. Are there examples of organisms with multiple nucleuses? If not, is there a reason?
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Can a gene be inactivated using CRISPR if it is not in the interspace of short palindromic repeats?

I have recently studied how CRISPR works but there is something that I do not understand at all. I have heard a lot of people claiming that with this method it is possible to modify any genome by ...
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Chromonema and Chromonemata

A chromonemata is composed of two chromonema. Which are again composed of chromatin fibre. Thus my question is chromonemata is composed of how many chromatin fibre ?
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Can proteins from different viruses be gathered in one virus?

There is a biology project I must do with some of my classmates and we're facing a problem. We would like to choose proteins from different viruses that seem interesting to us (for example one protein ...
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136 views

Why does deamination in the lagging strand lead to an increase in the relative number of guanine and thymine to cytosine and adenine?

My question arose from this article on Wikipedia on the GC-skew in bacterial genomes: https://en.wikipedia.org/wiki/GC_skew As far as I understood, the lagging strand (the template strand), during ...
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What is the expected amount of DNA shared by first cousins and the people between them in a family tree?

What is the expected amount of DNA that is shared by all of the people between first cousins, including the first cousins, in a family tree?
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How did biologists find out that bacterial plasmids were circular?

I was always curious how it was determined that bacterial plasmids were circular, since there isn't an obvious way to find this out. I heard somewhere that there was a difference when gel ...
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DNA of cellular organelle

Why do some cellular organelles like mitochondria and plastids have their own DNA. And what is the basic difference between the DNA of the nucleus and these organelles?
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Do non-functional (‘junk’) protein sequences exist?

For DNA one can distinguish between protein-coding DNA sequences, i.e. nucleic acid sequences inside DNA (vs. non-coding sequences) DNA sequences that do not code for proteins but are transcribed ...
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Trying to extract DNA with an incomplete kit

I'm wanting to run a DNA extraction on soil and root samples using a 96-well plate kit. My problem is that someone has gone through the kit and taken the Sealing Tape. This tape it used to seal the ...
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525 views

Don't understand how multiple replication bubbles work

I'm not exactly sure how multiple replication bubbles work, assuming were working with a linear, eukaryotic chromosome. This is a diagram for reference: It appears that the DNA is being synthesized "...
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DNA quantification in a high school bio lab

I'm working on a project in a high school bio lab (so limited resources), and I need a way to quantify the concentration of DNA in a PCR product. I can't use spectrophotometry (cheap ...
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2answers
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Question about phylogenies and DNA sequencing

I'm reading this web page which talks about phylogenies and DNA sequencing: https://bioinf.comav.upv.es/courses/biotech3/theory/phylogeny.html A certain sentence says, "If we consider dolphins and ...
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136 views

Misunderstanding about nucleotide biosynthesis

Some months ago, I asked what was a phosphoester bond, because I didn't really understand the following picture and explanations provided in the "Molecular biology of the gene" from Watson, Baker, ...
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How is single nucleotide polymorphism denoted?

Currently I'm studying an article on TERT promoter mutations in human melanoma and find myself unfamiliar with included denotations,I would appreciate it if someone could explain to me what C228T in ...
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Dilute DNA plasmids with distilled water

I just extracted the DNA plasmid from E.Coli and dilute them in EB buffer. However, I've just figured out that the next step, which is electroporation, required that the DNA plasmid be diluted in ...
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44 views

Meiosis and combinations of chromosomes

I was pondering about the genetics of siblings. It occured to me that a pair of biological brother and sister (not brothers or sisters) could inherit completely distinct sets of chromosomes from their ...
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44 views

Do single nucleotides spontaneously bind to ss DNA?

Do single nucleotides spontaneously bind to ss DNA? AT. GC. I realize the rhibisome is usually needed for making a strand, but what about randomly hbonded base pairs? Does this occur?
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How many polynucleotides are there in one molecule of DNA?

I always thought that a molecule of DNA was made of two polynucleotides each making up one strand of the molecule... Is that right?
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2answers
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Is a single polynucleotide necessarily and always a nucleic acid?

I am confused. I know that a DNA molecule is made of two polynucleotides. But does each polynucleotide represent one nucleic acid? If so, a DNA molecule is made of two nucleic acids, right? Or do ...
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265 views

How many nucleic acids is there in “one molecule of DNA”? [duplicate]

I am confused... People usually say that "DNA" is made of two strands deoxyribonucleic acid bound together. Nonetheless, the acronym "DNA" means "deoxyribonucleic acid". So by logic, a molecule of "...
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2answers
137 views

How do biologists determine the parents of a child

I am not well-versed in biology so this question might be wrong. As far as I understand meiosis, two germ line cells with 23 chromosomes each (one cell from the father and another from the mother) ...
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what kind of bonds join the okazaki fragments

During DNA replication, the synthesized okazaki fragments adjacent to each other are joined up directly by DNA ligase-catalyzed phosphodiester bond formation. Can someone point out to me which part of ...
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What determines the differences between differentiated cells?

Given two multi-cellular species with obviously different phenotypes. The reason for the different phenotypes reflects their different DNA. However two types of cells in an adult organism may have ...
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0answers
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Dyes that won’t bind to dna

I am looking for a dye that won’t bind to DNA. I want to add dye to proteinase K to make is visible when adding to clear buffer liquid samples. I need it to not bind to the DNA so it will be removed ...
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Why can't primary RNA be used as a direct template for a protein? [closed]

Why can't primary RNA be used as a direct template for a protein
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Is tunneling of a proton in our DNA a cause of mutations?

Our DNA strands are tight together by hydrogen bonds. Can the proton of Hydrogen tunnel to the other complementary strand, and by this during the replication bind to a different/wrong nucleotide, ...
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167 views

Why is the outer circle of human mitochondrial DNA ‘heavy’, whereas the inner circle is ‘light’?

Why is the outer circle of human mitochondrial DNA "heavy" whereas the inner circle is "light"?
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what happens when you put enhancer and caat box in prokaryotes

what happens when you put enhancer and caat box in prokaryotes
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Cutting dna using restriction endonuclease

Genomic dna is digested with alu 1 which is a four base pair cutter. What is the frequency with wich it will cut the dna assuming a normal distribution of bases. (this is not a homework)
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78 views

How do I go about traveling with DNA extract samples?

I am traveling from Fairbanks, Alaska to Vienna, Austria in six weeks and need to bring 10 very small (~50 ul) samples of extracted arctic ground squirrel DNA with me. I need to travel with these on ...
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0answers
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Can a phosphodiester bond form between RNA and DNA?

In the initiation of DNA synthesis: the RNA segments are first synthesized by primase and then elongated by DNA polymerase (Wikipedia). What does 'elongated' mean in this context? Is it possible ...
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1answer
185 views

What is the justification of Chargaff's second parity rule?

First parity rule The first rule holds that a double-stranded DNA molecule globally has percentage base pair equality: %A = %T and %G = %C. The rigorous validation of the rule constitutes the ...
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Organisms that do not wish to reproduce [duplicate]

Are there any organisms that do not want to reproduce? As humans, there are people who do not want to reproduce with the opposite sex. Do any other organisms replicate this behavior? Also, why does ...
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2answers
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What is the likelihood of a single human gene to the same gene from the other human?

The human genome comprises 3,234.83 Megabases and contains ~ 19,000 genes. It has been estimated that the genomes of humans are 99.9% identical. How likely is it that any single gene might vary from ...
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139 views

Enhancer elements in prokaryotic DNA?

I know that in terms of post-translational modifications of genes, prokaryotes and eukaryotes differ highly because of the lack of introns in prokaryotic DNA. With this said, do prokaryotic DNA ...
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Can we detect the origin of a 1000 year old dead body after grave excavation?

I recently read an article saying DNA analysis has shown some of the people buried in Viking graves in Scandinavia originated from places like Persia and it is talking about something around 1000 ...
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227 views

Can CRISPR-Cas9 make changes on a living organism?

Can CRISPR-Cas9 make changes on a living organism? What's the limit here? E.g. reversing/restoring hearing loss in a living adult mice.
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Would we improve our health if we removed all of our useless DNA?

(Just for curiosity. I am not a biologist) Suppose that we someday uncover all the secrets that our DNA might contain and discover that more than half of it is useless and doesn't encode anything in ...
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39 views

How do people actually find codons in a DNA transcript just by looking at it?

I was looking at this transcript of a DNA sequence, and the article kept referencing what the first codons are, but a codon like AUG isn't in the sequence...there's no "U" in any sequence. What am I ...
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What is the difference between average sperm epimutations and intersection sperm epimutations, in the context of the attached article?

The paper of interest is Manikkam et al. (2014). In research for a school Year 10 Science project, I came upon this article and the following two graphics. I don’t quite understand the difference ...
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187 views

Why does DNA need to be pure for restriction enzymes to act on it?

My textbook states: “In order to cut the DNA with restriction enzymes, it needs to be in pure form, free from other macromolecules. Therefore DNA isolated from other chemicals of the protoplasm like ...
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DNA Longevity in Keratin, Ivory and other Bioplastics

For how long is DNA viable for extraction and/or sequencing in bioplastics created by the human body? I checked out a few links online, and this article gives a record of about 7000 years for frozen ...
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How do cells become differentiated using epigenetics despite having the same genome?

How is epigenetics used in the differentiation of cells and is this the only thing that is used? I've seen that transcription factors play a role but are these simply proteins that initially write the ...
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Is a DNA molecule a single strand of polynucleotide or two of them linked together?

I'm so embarrassed to ask such a question here, but our molecular biology teacher told us that a double helix of DNA was composed of two DNA molecules linked together by hydrogen bonds. The thing is, ...
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225 views

why is DNA better for storing genetic info while RNA better for transmission of it?

I do know that RNA cannot be used for transmission since it is unstable, but how does it prove to be a better transmitter of genetic information?
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1answer
63 views

de novo assembly applications

Hey I hope this question supposed to be in this forum. I'm not from the biology community, I'm from the data security community so im not familiar with the words you might use for answers I need to ...
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DNA replication, why complex [duplicate]

When the DNA replicates, it first attaches RNA since the DNA polymerase can't attach DNA in the 3' end. Why the replication is happened this way? If the DNA polymerase can attach DNA from the 3', the ...