Greetings good people,
I dimly remember a suggestion that pure, (ie uncontaminated), Human DNA acts as a carcinogen for Homo Sapiens, anyone else heard this or can shed some light?
Peter
Bwhuh? Are you talking about exposure to purified DNA through ingestion or some other means? Or does this have something to do with the fact that we have genes that can cause cancer if misregulated? Or the mutations that result from copying errors or other normal processes? I can’t tell what you’re referring to.
No, eating DNA will not act as a carcinogen, if that’s what you’re asking.
Yes, if you mean “all cancers are at root genetic (i.e. DNA) aberrations.”
Thanks for the quick post, Because I can’t remember the exact details of the original premise I’m assuming any form of physical contact ingestion, touch etc.
It’s been an odd niggling thought that has occasionaly bugged me for years and this is one of the very few sites where I’d expect some sort of credible response.
Peter
I’m not sure, but I think you have to distinguish between the deoxyribose sugar which is just the back bone of the helix and should be utterly harmless and the C-A-T-G (cytosine, guanine, thymine, adenine) base pairs.
But even then, to cause cancer, you would need something like a shotgun type of hybridization vector where you literally load up a small projectile with the DNA segments you want to transfect and then slam, bam thank you mam, hit the target cells with it. However that’s not usually done to create cancers, but since we’re talking hypothetically . . .
BTW, I did used to take a supplement of yeast RNA and DNA. I went for a PCR HIV test once and it actually picked up one of the codons from the yeast as matching the virus. I don’t know for sure it was the yeast DNA except that a) I didn’t have HIV and b) the next test done with no yeast supplement was clean.
It was not the yeast.
It was only one codon. What makes you so certain? 
Is a yeast codon any different from a retroviral codon or a human codon?
Also, isn’t PCR used for viral load? I don’t think any PCR test is done for diagnosis.
A codon is a just a coding sequence of 3 bases guys. It codes for a single protein. You can have overlap between any and all kinds of eukaryotes.
And yes, PCR is done for diagnosis, it’s just not common since the antibody tests are cheaper. But PCR is much more accurate since it tests directly for the viral genetic material.
Plus, at least in Canada, the antibody tests fall under specific-consent laws, but direct viral testing doesn’t. Useful in cases of needlestick injuries.
For starters, it is quite unlikely that any of the yeast DNA (or RNA) would turn up in your blood with its primary structure still intact.
What is “it was only one codon” supposed to mean, by the way? Codons are essentially meaningless for PCR. What are you basing that statement on?
A codon specifies a single amino acid (or stop-translation signal), not a protein. An amino acid is a protein monomer (“building block”). This is why your statement doesn’t make sense. Saying a PCR-based screen picked up an “HIV codon” is the same as saying there is a unique three-base sequence that appears in the HIV genome but not in other genomes.
Apart from the fact that a single codon represents an amino acid, not a protein, this is true — but also trivial. Of course many organisms use the same genetic code, but so what? It’s the order of those codons in a gene that makes the difference.
You fail Bio101! A codon codes for an amino acid…not a protein. My question is whether there is a difference between yeast, viral and human codons. I’m fairly certain they are identical.
Also, l am fairly certain that diagnosis of HIV infection is done by an ELISA and a Western blot…neither of which involve PCR. I guess it could have changed recently but I haven’t heard about it. Got a cite?
This thread is making my head hurt. Let’s start with some definitions:
A codon is a sequence of three nucleotides that codes for a single amino acid. Proteins are made of many amino acids (dozens to thousands). Almost all life uses the exact same codons, viruses and humans included.
PCR is a test that identifies much larger sequences, with a minimum around ~50 nucleotides. You cannot detect a codon with PCR.
HIV DNA has very little in common with either human or yeast DNA. Yeast DNA would not be detected by the HIV PCR test – something else caused the false positive.
And getting back to the OP, the only way that DNA could be a carcinogen is as DeltaSigma refers to: blast cells with huge quantities of a particular cancer-causing gene. To do this to a human, you’d need to deliver the DNA with something like a virus or gene gun.
Sorry, got sloppy with the terminology.
You really only need the first 2 bases for each amino in most cases, so there can be a great deal of overlap.
I had this test done in the early 90’s right after PCR became commercially available and at least a decade before most people even heard of it, so I really do have some idea what I’m talking about. I’m not a molecular biologist, but I was involved with one who did basic research research at places like Columbia and part of why we met was because it was an area of intense interest for me long before that.
If you want a cite, just look up PCR. It amplifies DNA to the point where you can test for it directly. It use a polymerase isolated from an archaea that is heat sensitive such that when you cycle the heat up I think, the DNA denatures and the polymerase can read it and match up the bases. Something like that. It’s been a while. The point is that it’s specific to DNA I think you just have to give it the right transcription sequence (?).
Dude, if you can identify an individual amino, you have virtually identified the codon (overlooking the fact that that there are probably 2 codons for the same amino).
Anyway, I’m telling you what the people from Specialty Labs told me - they were the first lab in the country to do the PCR test so I think they probably knew a little more about it than you do.
I will however admit that the part about the yeast is speculation, but I said that from the start. It is NOT however something that can be rejected apriori - that’s just bullshit.
Be that as it may, they never said anything about codons or yeast, did they?
Yes, it can. All it has going for it is your post hoc ergo propter hoc reasoning.
They SPECIFICALLY said that it matched up to one of the HIV codons. That is an EXACT QUOTE. Of course I don’t expect you to believe me, but as long as you don’t ask me if I care, we should be copacetic.
Whelp, I am a molecular biologist, so I do know what I am talking about. I am quite familiar with PCR genotype techniques. I have no doubt that the people who developed this HIV test know a little more about its particulars than I do, but it is clear that you do not.
If that’s an exact quote, it was in error. Or your memory of a twenty year old quote is imperfect.
What we are trying to tell you is that the very concept of an HIV-specific codon is nonsensical. There is simply no such thing as a codon specific to any one genome. This is like saying a torn page from a book is from War and Peace because the letter A in a sentence matches a letter A from the book.
A PCR-based test of the type used to detect HIV uses a pair of primers specific for a known region of the target’s genome. Primers are typically 18-25 nucleotides long. They are not for single codon, and don’t even have to be from a protein-coding region. If the target is present, the primers will anneal to the target at the specified locations and provide a free end for the polymerase to synthesize the specified region. After the reaction, a large pool of copies will be present and detectable.
That said, PCR can produce a false positive by chance all on its own. No yeast interference necessary. The primers can occasionally misanneal to a different target, the test can get contaminated at the lab, or you could even have a few non-functional fragments of the test target’s genome in you, among other possibilities.
It has been over 20 years since you had the test done. Which is more likely, you have misremembered what was reported, or the test did something which is not only impossible but nonsensical?