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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Is telomere shortening consistant over consecutive cell divisions from zygote to a differentiated cell?

Considering the complexity of embryogenesis, a temporal referance would be helpful to coordinate the developmental sequences during embryogenesis and fetal development which is to be completed within ...
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More entropy: Atom or Macromolecule? [closed]

A question that appeared on my last exam was : Which of the following has greater entropy A) An atom B) A macromolecule The question doesn't specify anything else(i.e. type/size of atom or ...
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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 ...
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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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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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Turning publicly available genome data into proteins

I'm a computer scientist who is starting to dabble with biology. My eventual goal is to model different kinds of cells with a computer program. As of right now, I'm just trying to take some smaller ...
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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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39 views

To what extent is it possible to understand if a bacteria can produce a protein? (in silico only!)

I have to answer a question about a sub-task of my thesis: Can the bacteria X produce the protein Y? I searched of course Google and BLAST. There is no data supporting that this specific bacteria ...
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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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84 views

How much DNA of Albert Einstein is recoverable?

Since there seem to be five biological descendants of Albert Einstein, and the original chromosomes of him distributed among them ... Is it possible to recover enough DNA of an individual from his ...
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130 views

What makes DNA helical?

Why isn't DNA like RNA; why isn't RNA like DNA, that is, helical? Why are RNA chains straight?
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56 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 ...
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92 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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83 views

is it possible to completely reconstruct a family tree by DNA comparison alone?

Having DNA samples of all or almost all members of a population of, say, a few hundred or thousand individuals, is it possible to draw the entire family tree of those individuals? (Let's not assume ...
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986 views

Difference in length of Okazaki fragments

The length of Okazaki fragments in the lagging strand is about 100-200 nucleotides in eukaryotes and about 1000-2000 nucleotides in prokaryotes. What (molecular mechanism, enzyme type ) ...
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19 views

book on genealogy, haplogroups, migrations, etc

Looking for a popular science book on the topic. I need a wide-angle expose, not fiddling with minor details. It should also be somehow intertwined with migration. I've recently learned, for example, ...
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24 views

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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62 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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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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1answer
38 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 ...
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3answers
69 views

dsDNA translation

Since DNA is double stranded and each strand is complementary to the other, the codons on each strand will come out to be different after transcription(depending on the reading frame). Does this mean ...
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1answer
45 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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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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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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Genes, chromosomes, base pairs and the 23 pairs

OK so I'm a bit confused. Does a chromosome consist of genes and do genes consist of DNA? What about the 23 pairs in sexual reproduction? I can't remember what the pairs consist of
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47 views

How was Restriction Site of EcoRI sequenced?

The sequence of restriction site of EcoRI - GAATTC was identified in the early 1970s, before Sanger Sequencing was invented.(1977) How was the restriction site of EcoRI sequenced ?
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Evolutionarily speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
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What is most simple eukaryotic genome?

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

Why Only DNA can Contain Hereditary Material?

Well I'm well aware that it is proven that DNA contains genetic material via transformation and Hershey-Chase Experiment of T2 bacteriophage. Still I was wondering what is the reason only DNA ...
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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 ...
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30 views

What information do microarray image convey?

OK I have read that a cell generates 4 kinds of digital (to be precise discrete) data namely DNA, RNA, Protein (sequences that can be encoded as string sequences of nucleotides/ amino acids) and micro ...
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Why are there exactly four nucleobases in DNA?

Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
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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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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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Why are 3 nucleotides used as codons for amino-acid mapping in DNA?

DNA is made of 4 unique nucleotides. When coding for a protein, a sequence of 3 nucleotides is used to code for each amino acid. Why are codons 3 nucleotides in length? A related question can be ...
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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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16 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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50 views

how does DNA and RNA work [closed]

How do the DNA modules tell the cell what to do?
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81 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? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and energy)? time to copy is ...
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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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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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Does the genetic material the sperm carries affect it's physical properties

Basically, what I'm asking is, is the actual sperm cell built from the blueprint in the DNA of the man or is it itself also a consequence of the DNA it carries? I'd like to know a few more things ...
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68 views

How does GC-content evolve?

Background GC-content refers to the frequency of base pairs that are either C or G in the genome, or in other words the number of GC base pairs divided by the addition of the number of GC base pairs ...
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51 views

relative-rate of evolution

I am supposed to calculate the relative rate of evolution of two sequences (human and sheep) with a chicken serving as the outgroup. The sequences are pretty long, so I will just create a short ...
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1answer
369 views

Why do three nucleotides code for one amino acid? Why not 5 nucleotides? [duplicate]

We all know why there are 3-base codons, and why there aren't any 2-base codons. But why is there not a 4-base a 5-base codon?
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336 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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44 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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37 views

In what circumstances does a mammalian egg copy its DNA?

In the 2nd episode of the new Cosmos series, the host Neil deGrasse Tyson shows how the white-furred bear could have evolved (reasonable scientific speculation, of course). If you haven't seen that ...
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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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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. ...