Skip to comments.Gonorrhea acquires a piece of human DNA
Posted on 02/13/2011 2:39:33 PM PST by decimon
First evidence of gene transfer from human host to bacterial pathogen offers new view of evolution, disease
CHICAGO --- If a human cell and a bacterial cell met at a speed-dating event, they would never be expected to exchange phone numbers, much less genetic material. In more scientific terms, a direct transfer of DNA has never been recorded from humans to bacteria.
Until now. Northwestern Medicine researchers have discovered the first evidence of a human DNA fragment in a bacterial genome in this case, Neisseria gonorrhoeae, the bacterium that causes gonorrhea. Further research showed the gene transfer appears to be a recent evolutionary event.
The discovery offers insight into evolution as well as gonorrhea's nimble ability to continually adapt and survive in its human hosts. Gonorrhea, which is transmitted through sexual contact, is one of the oldest recorded diseases and one of a few exclusive to humans.
"This has evolutionary significance because it shows you can take broad evolutionary steps when you're able to acquire these pieces of DNA," said study senior author Hank Seifert, professor of microbiology and immunology at Northwestern University Feinberg School of Medicine. "The bacterium is getting a genetic sequence from the very host it's infecting. That could have far reaching implications as far as how the bacteria can adapt to the host."
It's known that gene transfer occurs between different bacteria and even between bacteria and yeast cells. "But human DNA to a bacterium is a very large jump," said lead author Mark Anderson, a postdoctoral fellow in microbiology. "This bacterium had to overcome several obstacles in order to acquire this DNA sequence."
The paper will be published Feb. 14 in the online journal mBio.
The finding suggests gonorrhea's ability to acquire DNA from its human host may enable it to develop new and different strains of itself. "But whether this particular event has provided an advantage for the gonorrhea bacterium, we don't know yet, " Seifert said.
Every year an estimated 700,000 people in the United States and 50 million worldwide acquire gonorrhea. While the disease is curable with antibiotics, only one drug is now recommended for treatment because the disease developed resistance to previously used antibiotic options over the past four decades.
Gonorrhea is a particularly serious disease for women. If left untreated, gonorrhea can lead to pelvic inflammatory disease, a painful condition that can cause sterility and ectopic pregnancy. In rare cases, men and women can develop a form of the disease that leaves the genital tract and enters the bloodstream, causing arthritis and endocarditis, an infection of the inner lining of the heart.
An ancient disease that sounds like gonorrhea is described in the Bible, noted Seifert, who has studied the disease for 28 years. Most of his research focuses on how the bacterium evades the human immune system by altering its appearance and modulating the action of white blood cells.
The gene transfer was discovered when the genomic sequences of several gonorrhea clinical isolates were determined at the Broad Institute in Cambridge, Mass. Three of the 14 isolates had a piece of DNA where the sequence of DNA bases (A's, T's, C's and G's) was identical to an L1 DNA element found in humans.
In Seifert's Feinberg lab, Anderson sequenced the fragment to reconfirm it was indeed identical to the human one. He also showed that this human sequence is present in about 11 percent of the screened gonorrhea isolates.
Anderson also screened the bacterium that causes meningitis, Neisseria meningitidis, and is very closely related to gonorrhea bacteria at the genetic level. There was no sign of the human fragment, suggesting the gene transfer is a recent evolutionary event.
"The next step is to figure out what this piece of DNA is doing," Seifert said.
The research was sponsored by the National Institutes of Health.
NORTHWESTERN NEWS: www.northwestern.edu/newscenter/
“Every year an estimated 700,000 people in the United States and 50 million worldwide acquire gonorrhea. While the disease is curable with antibiotics, only one drug is now recommended for treatment because the disease developed resistance to previously used antibiotic options over the past four decades.”
...and considering that the drug makers have pretty much thrown in the towel, once Gonorrhea gets resistance to this last drug, look for it to make a surging comeback here.
...and maybe that will slow down our free-love culture, at least somewhat. So not necessarily all bad news.
In this case, I think "Clap" may have been more appropriate.
Sorta like converting to Islam.
In this case, I think "Clap" may have been more appropriate.
I wouldn't want the thread to go viral, so to speak.
LOL....you forgot to alert Spirochete...
The “Slick-Willy” gene.
"Together we thrive!"
As Uncle Milty would have said:
There's no such thing as a free hook-up.
eating barrys what???...oh...nevvverrrmind...
“As Uncle Milty would have said: There’s no such thing as a free hook-up. “
If Gongareea (as Rush calls it) pulls off this next mutation, there are going to be a LOT of liberal women suffering life-changing consequences, thanks to the health care system they worked so hard to dismantle.
People have scoffed in the face of God; and now they’ve literally become a part of what they’ve embraced.
I’m elated to say that no doctor has ever told me, “The disease that you have is nothing to ‘clap’ about.”
“An ancient disease that sounds like gonorrhea is described in the Bible, noted Seifert, who has studied the disease for 28 years.”
I guess we need dedicated people in the world like Seifert here, but, Man...what a life - studying the clap.
Clap, clap, clap,
they call him the clapper
The perfect Valentine's Day gift.
So, which came first in the evolutionary scheme?
The human or the clap virus?
Terrific! This news REALLY makes me want to get right out there and date again, LOL!
On the other hand, my documented clean bill of health will definitely be a HUGE bargaining chip when I’m ‘Husband Hunting’ again in the future.
Sounds like time for a major rewrite of evolutionary theory.
It is known that the human genome has integrated the entire RNA of some viruses, over the course of a vast amount of time. However, if a bacteria can get DNA from us, it could leap frog millions of years of ordinary evolution.
You mean like the way AIDs has slowed down the gay "free love" culture. Oh,wait.
It would be nice to think that people would start to wise up; but, I think they would just whine a lot and insist somebody come up with a cure.
They'll be so happy they're already getting their own internet jargon!
They don’t know, yet. Give them time to research it.
This may give medical researchers a new chance at a cure for the disease, one not involving antibiotics.
Turns out he infected it.
REAL scientists won’t go there unless they have proof. These guys do not seem like the climate prediction loonies.
“You mean like the way AIDs has slowed down the gay “free love” culture. Oh,wait.”
It did, a bit, around 1990. Then they found enough drugs to let them survive and they came back with a vengeance.
The human immune system is already pretty amazing.
Shuffling DNA around to come up with a structure that binds to just about every possible 3-D molecular shape? WOW!
Nobody supposes it alters the DNA of a bacteria; but if you have any evidence of it, I am all ears! Meanwhile there are many mechanisms bacteria have to acquire DNA for foreign sources and put them to use.
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Getting inside a cell and changing DNA is what a virus is good at. Our immune system doesn't produce viral structures.
Attaching antibodies (those 3-D shapes) to pathogens and using pyrogens and killer cells - THAT the immune system does.
Introducing DNA changes to the pathogens that prey upon you is an ineffective method, because you cannot ‘get’ them all at once, and the more detrimental the disadvantage, the more those unaffected will dominate subsequent generations.
So even if the immune system...
a) created viral like particles that could enter the bacterial cell and introduce new DNA.
b) the new DNA was to the disadvantage of the bacteria.
c) the bacteria with the disadvantage would be out-competed by those without it.
So...at last, gonorrhea caught us!
BOLO the audience clapping gif...
I can't help thinking about what this means for those who fool around. The odds for those who are young and not sexually active, for those in a monogamous relationship, and for those who abstain from sex are all excellent. As for those who engage in casual sex or who patronize prostitutes, the odds are not pretty.
Yes there is. Bacteria are not only adept at gaining foreign DNA, they are ‘experts’ at getting rid of any DNA that isn’t ‘worth its salt’.
If any at all present in your body didn’t get the DNA your immune system (by some unknown mechanism) was introducing, then those that didn’t get the DNA would dominate subsequent generations. Those that gained it would experience selective pressure to rid themselves of it, and any mutation that rendered it inoperable would be favored.
It would be, first of all an amazing unknown mechanism, and secondly - an attempt to beat a bacteria at its own game.
You don’t win that way, it is an outlandish strategy presupposing unknown mechanisms that, even if true, wouldn’t be effective.
Reality is, by most accounts, weird enough. Our immune system introducing DNA into bacteria is weird, but not weird enough - because it wouldn’t work.
Excellent and astute series of replies. Thanks for sharing.
They refer to the human sequence the bacteria has acquired as an “element”. This usually denotes a sequence of DNA that is bound by a specific 3-D protein, usually a transcription activator or repressor.
For example, the difference between lactose tolerance as an adult and lactose intolerance is a mutation in a transcription repressor ‘element’ near the lactose gene. In almost all mammals this repressor turns off the gene in adulthood, in Northern European populations and some African cattle herding populations this DNA ‘element’ is mutated, so that the lactose gene is expressed as an adult.
It will be interesting to see what, if anything, this DNA is doing, and what advantage (if any) it confers upon those bacteria with it.
I never said a bacteria was “too smart”. That is your own misconception.
Evolution would work against your proposed mechanism, there is no “smart” required.
A change in the dangerous characteristics of an invading pathogen through introduction of new DNA into its genome would not work for the three reasons I already outlined, and there was no “smart” required from the bacteria in either....
1) unknown mechanism completely removed from anything observed in how the immune system works. This is obviously the weakest objection because absence of evidence is not evidence of absence. But it presupposes a rather complex and bizarre mechanism that has never been observed, Occum’s razor precludes taking this assumption seriously without any evidence. This MIGHT be evidence of what you suggest, but first we will have to see what the human DNA element is doing in the bacteria and if having it is advantageous or disadvantageous for the bacteria.
2) Even if the mechanism existed and was highly effective at introducing human DNA into the bacteria, natural selection would favor any that were not affected until they dominated each subsequent generation.
3) Selective pressure would work towards elimination or mutation of the foreign DNA sequence if it conferred a disadvantage.
It might be easier to deal with the arguments I didn't make, but it isn't exactly logical discourse at that point, is it? Can you deal with the arguments I actually DID make?
They are “experts” in that bacteria routinely gain and rid themselves of foreign DNA. It is a trait, a characteristic, an intrinsic property.
Yes, natural selection.
If 10% of the bacterial population has the human DNA and it is advantageous there will eventually be 11% of the bacterial population that will have that trait.
It is a mathematical inevitability.
If it is disadvantageous then eventually only 9% of the population will have that trait.
That is why a fantastical mechanism whereby the immune system would add DNA to a bacteria would be idiotic, because the more detrimental the trait it passed on - the quicker it would be selected against and eliminated from the population.
The immune system is in the business of identifying foreign 3D structures and KILLING THEM, not messing with their DNA in the hopes that it will make them act nicer.
I mean what sense does that make? But I sense where you are coming from, and it doesn't seem so strange now that you prefer fantastical illogical magical mechanisms to actual science.