Deoxyribonucleic acid (DNA) is the carrier of genetic information, including for all known living organisms. The only known exceptions are RNA viruses.

learn more… | top users | synonyms

57
votes
4answers
34k views

Why is uracil used in RNA rather than thymine?

What is the advantage gained by the substitution of thymine with uracil? I have read previously that it is due to thymine being "better protected" and therefore more suited to the storage role of ...
2
votes
1answer
48 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 ...
0
votes
1answer
30 views

PCR cycle problem [closed]

IF I began a PCR cycle with 5 copies of a particular DNA section, and copied the section by PCR, for 6 cycles, how many copies of the DNA (include the originals) would I have by the end of these ...
3
votes
1answer
75 views

Is a single x-ray photon capable of doing enough damage to the DNA of a cell to kill that cell? [closed]

Ionizing radiation is damaging to DNA, but is there such a thing as a safe dose below which no DNA damage could occur? I'm not asking about a minimum safe dose overall, just whether or not there's an ...
5
votes
3answers
169 views

What makes DNA sticky-ends sticky?

When restriction enzymes jaggedly cut double stranded DNA it results in so called sticky ends. What is the substance that makes the DNA sticky?
1
vote
1answer
53 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 ...
1
vote
1answer
168 views

Ribosomal Turing Machines, DNA/RNA computation

I'm a computer science guy, recently crossing over to do some research in computational biology on RNA secondary structure prediction. While looking through the materials I got a crazy idea, what if ...
-5
votes
1answer
66 views

Are there any similarities in the DNA of a humans and animals? [closed]

As the title says, i've been wondering if there are any similarities between the DNA of humans and the DNA of animals? Like, maybe monkeys are more similiar in their DNA to humans, than dogs are (to ...
6
votes
1answer
663 views

Why does A pair with T and G with C?

DNA is made up of pairs on AT and GC base pairs. I know that A only pairs with T and G only with C. Does this apply just to humans, or are there animals where T will pair with G? Also, surely there ...
0
votes
1answer
114 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 ...
5
votes
1answer
84 views

enzymes that stabilize DNA loops

As a follow-up of a previous question, I would like to know what enzymes or protein complexes have been used to manipulate DNA samples into stabilizing DNA loops. I have read that cohesin is one of ...
1
vote
1answer
34 views

Is the nuclear envelope present in G1 of interphase?

Is the nuclear envelope present in G1 of interphase of eukaryotic cell? If so how does a method like Calcium mediated transfection get DNA past the nuclear envelope?
4
votes
2answers
670 views

Importance of Double Helix DNA Structure

Gene expression involves transcribing only one strand of DNA molecule. So i was wondering what are some biological advantages of the double stranded DNA?
1
vote
1answer
130 views

Why is the threshold between human embryo and human fetus defined as 8 weeks after fertilization?

Why is the threshold between human embryo and human fetus defined as 8 weeks after fertilization? What's happening on the 8th week? Note: definition of embryo based on Wikipedia's current ...
9
votes
1answer
116 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and ...
2
votes
0answers
17 views

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 ...
6
votes
2answers
218 views

Can forensic DNA analysis be used to generate a visual approximation of a suspect?

In light of the current US supreme court case, I'm curious if enough information can be teased out of a DNA sample to get a "reasonable" approximation of the suspect (never mind the legality). I ...
3
votes
2answers
29k views

What does 5' and 3' mean in DNA and RNA strands?

What are 5' and 3' in DNA and RNA strands? Please clarify with some images and please use simple English.
4
votes
1answer
74 views

Redundancy of the genetic code

One particular codon codes only for one amino acid, but an amino acid can be coded for by several different codons. Now according to the genetic code, the codon UUU ...
1
vote
2answers
74 views

What kind of technology is required for plant seed DNA printing? [closed]

I'm a programmer so I have little knowledge in the field of biology. However I have an interest in plants, GMOs and DNA (in terms of programming). So, I want to know what kind of technology is ...
1
vote
2answers
65 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 ...
2
votes
2answers
96 views

How does non-homologous end joining (NHEJ) work?

I was reading about non-homologous end joining (NHEJ) in my molecular biology of the gene textbook but the explanation provided in the text was rather vague to me, and I was not able to understand it ...
2
votes
1answer
187 views

Does DNA replication in 5' to 3' (leading strand) need RNA primase?

https://www.youtube.com/watch?v=27TxKoFU2Nw In the above video it shows that during DNA replication, the lagging strand require RNA primase to add 3' -OH group for further addition of nucleotides. ...
3
votes
0answers
24 views

Gibson assembly - primer design with A and T rich regions

I have question about Gibson assembly. I have done it several times and it always worked okay for us, but now I want to assemble together a fragment which has sequence like this: ...
2
votes
1answer
94 views

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 ...
0
votes
2answers
74 views

If DNA is the input, what is the output? [closed]

How does cells use the DNA inside them? I am looking on DNA as a strip of tape of Turing machine, but with machines its easy. I can read the tape and calculate the behavior of that machine. With cells ...
0
votes
2answers
70 views

Chromatids in metaphase?

Please see the following picture: In my book, the author claims that these chromosomes are in metaphase (a metaphase stopped by cholchicin). I don't understand why they don't have two ...
2
votes
2answers
59 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 ...
1
vote
1answer
35 views

programmatic fast search of 100-1000 short reads to a public server and obtain list of nearby genes

What are the options for programmatic fast searching of 100-1000 short reads to a public server and obtain list of nearby genes where the reads map? Input: ~100-1000 short reads Output: GFF list of ...
12
votes
7answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
2
votes
1answer
47 views

How to identify genes?

You and me are different at DNA level. My eye color gene is different from yours. So, my DNA is different from yours. How can a scientist identify a certain gene in a chromosome (and its function) if ...
3
votes
1answer
69 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?
3
votes
3answers
3k views

Separating DNA Fragments by Gel Electrophoresis. Are all the strands for one size the same?

My apologies if my question is too basic, and please point me to a more appropriate forum. I am reading the textbook "Essential Cell Biology" by Alberts et al, and am consulting other sources as ...
5
votes
1answer
914 views

What is the fiber axis in the Watson and Crick paper?

I was reading Watson and Crick's article on DNA structure, and the diagram on the lower left of the first page had something called the fiber axis going through the DNA. This axis isn't in modern ...
7
votes
3answers
6k views

Does our DNA change during our lives?

As far as I know, DNA is the construction protocol of all organisms on Earth. Does it change when influenced by time and environment (physical laws)? As parents with schizophrenia are more likely to ...
13
votes
4answers
60k views

Why is DNA replication performed in the 5' to 3' direction?

DNA replication goes in the 5' to 3' direction because DNA polymerase acts on the 3'-OH of the existing strand for adding free nucleotides. Is there any biochemical reason why all organisms evolved to ...
1
vote
1answer
52 views

How is the rate of transcription influenced by temperature?

How is the rate of transcription influenced by temperature? More precisely, I am looking for an article who quantitatively measured the rate of transcription of an "average gene" and show how this ...
2
votes
1answer
29 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 ...
4
votes
2answers
48 views

where to find the relative frequency distribution of synonymous codons

Most amino acids can be encoded by more than one codon. For example, Serine can be encoded by any one of ...
1
vote
2answers
135 views

What is most simple eukaryotic genome?

Expressed in number of Base Pairs or Bytes, about how large is the simplest eukaryotic genome? How much of this is 'junk-DNA' (non-coding)?
1
vote
1answer
74 views

Has it been confirmed yet that the DNA found in dinosaurs was really DNA?

I hear different sources claiming different things, bbc said they did, wikipedia says it hasn't which is it?
7
votes
2answers
197 views

What causes skewed lanes in a DNA gel electrophoresis experiment?

In gel electrophoresis, what causes effects like these (see collumn 11 in the first one, an collumn 6 in the second). ? (These images were samples that I took from an online activity we did for ...
2
votes
1answer
131 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 ...
3
votes
1answer
34 views

How do nicks in the DNA strand affect the success of Long Range PCR?

Long Range PCR using NEB Master Mix - Hot Start Taq was working fine for me (amplicon sizes of ~10kb) but stopped working all of a sudden. Is it possible that many freeze-thaw cycles on the DNA ...
6
votes
1answer
138 views

DNA extraction from agarose gel

Because DNA is soluble in water, is it possible to extract PCR product by dissolving excised gel containing the DNA band of desired length in water, mashing the gel piece with a pestle, centrifuging ...
6
votes
1answer
53 views

What regulates the timing of the motion of molecular machines during DNA Replication?

This question is about this video I found on Youtube. I just want to know what is the mechanism which regulates the timing of motion of the parts of these molecular machines. I know that those big ...
2
votes
1answer
35 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 ...
0
votes
3answers
140 views

What is the purpose of DNA? [closed]

My very basic understanding is DNA gets transcribed into RNA by effectively replacing thymine with uracil, then RNA is translated to make proteins. Looking at it from an engineering perspective, it ...
7
votes
3answers
510 views

Possible reasons for DNA getting stuck in well

I am in the process of Library preparation for Illumina MI-Seq using mtDNA. Using NEB Hotstart LongAmp Polymerase, I was able to obtain upto 10kb amplicons of mtDNA. However, when I switched to a ...