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Stem Cells Change Man's DNA
Posted by
Zonk
on Fri Oct 05, 2007 04:21 PM
from the oh-man-science-is-weird dept.
from the oh-man-science-is-weird dept.
An anonymous reader writes "After receiving umbilical cord stem cells to replace bone marrow as treatment for non-Hodgkin's lymphoma, Greg Graves temporarily had three different sets of DNA. Eventually, one of the two sets of cells transplanted into his bone marrow took root, leaving him different DNA in his blood from the rest of his body: 'If you were to do a DNA test of my blood and one from my skin, they'd be different,' Graves said. 'It's a pretty wild thing.'"
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Submission: Stem cells change man's DNA by Anonymous Coward
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Beginning of the end? (Score:4, Interesting)
Re:Beginning of the end? (Score:5, Informative)
Parent
Re: (Score:2)
Re:Beginning of the end? (Score:4, Insightful)
Parent
Re:Beginning of the end? (Score:5, Insightful)
So if their DNA evidence came from skin or hair cells he could happily submit to a blood test to confirm that he's not the killer...all without their knowledge. Or vice-versa...they have blood and he says "Yeah, I'll give you a sample, but I don't like needles. Can we just do a cheek swab?"
Probably what this will lead to, if anything, is duplicate testing and/or testing of the same material as what was found. You find saliva, you test saliva. You find blood, you test blood.
Parent
scenario (Score:4, Insightful)
Fast forward 20 years - you have long since outgrown your reckless youth, are a responsible, caring member of society and as part of that you give blood and registered in the bone marrow database.
You're called - there's someone in another state that needs marrow, and you're a match! You're actually thrilled at the idea of being a part of saving a life. A young teenager needs your help. You know what it's like to be a teen who needs help.
Another 10 years pass and someone is murdered. Blood samples show not only the victim's blood, but the attacker's - she got in a few scratches before succumbing. They test the DNA, search the database, and BINGO - YOU'RE the match. You were on vacation in Barcelona, your wife swears its true. But hey, the expert says you have to be the guy, and so you get the death penalty for the vicious murder.
You could have gotten off with life in prison, but since you are so cold, so uncaring, so unwilling to show remorse for your crime, protesting your innocence all along, they show no mercy.
Parent
Re: (Score:3, Insightful)
Chimerism is old news but ignored (Score:3, Interesting)
Re:Beginning of the end? (Score:4, Funny)
"After all, there is no way of knowing for sure whether this cold-blooded murder was committed by my client, a 50 year old man from Portland, or by a 3-year old toddler from Orlando".
Parent
Re: (Score:3, Informative)
Reasonable Doubt.
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Re: (Score:2, Funny)
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Multple names and numbers (Score:2)
and your social security number, along with all the stolen numbers you've used,
then I'm sure they can find room, for a second set of DNA to be tied to you as well.
Crime adapts, science adapts (Score:4, Insightful)
Second, there are plenty of documented cases of someone being a "Chimera" where they contain two sets of DNA in their body. It's usually when an embryo absorbs a twin in the womb. I don't know if there are any true cases out there in the books where a Chimera was tried for a case, but it's known. Science is well aware that DNA is not 100% foolproof, which is why you have probability matches when testing DNA normally. These will simply be bumps in the road and science will adapt. This is nothing new to DNA research. Most likely forensics labs will begin to require taking multiple samples from multiple areas depending on the DNA evidence found. If you left blood at the scene of the crime, why take DNA from your cheek if there's a chance the criminal is a Chimera or a bone marrow transplantee.
Third, the law will catch up with this. Defense attorneys will use this to create reasonable doubt, and prosecutors will counter to learn about this, while forensics keeps up with the latest scientific trends.
On the other hand, DNA identification methods for businesses will be completely fucked if someone gets a marrow transplant or is a Chimera and doesn't know it.
Parent
You're missing his point. (Score:4, Insightful)
I think the responses so far are missing the OP's point.
I didn't read his post thinking, "OMG, no more DNA evidence within a few years!" I'm guessing he meant that eventually through the use of various technologies for various reasons, it will be possible for criminals to be genetically altered in such a way that making identifying them using DNA will be difficult. It may be 50 years, 100 years, or 200 years, but as we get better and better at munging up our DNA, it is possible.
Also, that totally neglects that at some point in the future, when the technology behind this kind of stuff becomes pervasive enough, high tech criminals may deliberately have their DNA altered for the specific purpose of thwarting identification.
Parent
Re:Beginning of the end? (Score:4, Informative)
http://en.wikipedia.org/wiki/Chimera_(genetics) [wikipedia.org]
Parent
Re: (Score:3, Interesting)
That reminds me of someone (Score:4, Funny)
The football team won that night, everybody scored.
Re:That reminds me of someone (Score:5, Funny)
Parent
Re: (Score:3, Funny)
Nothing stops me from that. Nothing.
first man-made chimera? (Score:3, Interesting)
Re: (Score:2)
Re:first man-made chimera? (Score:5, Informative)
First, he is not the first to have two sets of DNA due to a bone marrow transplant (although he might be one of the first with 3 sets). Anyone who has had an allogeneic (as opposed to autologous) bone marrow transplant like his has that, as do any other transplant recipients.
In fact, the differences between those DNA is both one of the best things and one of the worst things about alloBMTs to treat blood cancers. The new blood system sets itself up and sees the cancer cells as "foreign" and attacks them, what would be called "rejecting" them in a solid organ transplant. This is called "Graft Versus Leukemic Effect" in leukemia patients, for example. That's the good part. The bad part is that the new blood system looks at the rest of the body and sees it as foreign as well. "All this has to go" is the reaction, also called "Graft Versus Host Effect", or GVHD. That can kill you. Cord blood stem cells make this less likely to happen, because the cord blood cells are not quite sure what the other cells are supposed to look like yet.
The second reason he is not the first man-made chimera is that he is not a chimera. A chimera is when the second set of DNA comes from another species. That has been done before (organ transplants from pigs, for example), but is not the case in this story.
The real story here is that he had a stem cell transplant using cord blood from two different donors.
Parent
Re:first man-made Tetragametic Chimera (Score:5, Informative)
The Lydia Fairchild story [go.com] is an interesting read. It's rare but it does happen.
Parent
Re: (Score:3, Informative)
This is not true. Chimera is often used, outside of biology, to mean a creature made up of multiple species (a reference to Greek mythology) but in that instance you're not talking about biological chimerism, but some fiction where DNA is either not mentioned, or often is "merged" (cf Dark Angel.)
However, when you're talking genetics, which is what we're talking about here, you're talking about a being that is the product of two zygotes
So much for DNA evidence... (Score:2)
2. Shoot yourself up with stem cells
3. Don't get thrown in jail because the DNA from the crime scene doesn't match
4. Waitaminute... Profit belongs in step 1 in this case!
Re: So much for DNA evidence... (Score:5, Interesting)
Summary: Woman is a Chimera (two sets of DNA), and gets a paternity test, first one fails, second succeds because they take from another part of her body.
Parent
Re: (Score:3, Interesting)
This happens naturally in lots of people.
It even touches on the subject of pigmentation - where babies of interracial couples are born with "checkberboard" skin.
Allow me (Score:2)
2. Profit!
3. Inject Stem Cells
4. ????
5. Home Free
Re: (Score:2, Interesting)
Hope they tell the donor! (Score:2)
chimera (Score:2)
And this is news because...??? (Score:5, Informative)
This is nothing new. (Score:5, Informative)
The only thing remarkable about this is the fact that the stem cells the man received were from cord blood instead of adult stem cells from a matched donor.
Wikipedia has an excellent article on the subject: http://en.wikipedia.org/wiki/Stem_cell_transplantation [wikipedia.org]
The applicable section to this article reads as such:
"Umbilical cord blood is obtained when a mother donates her infant's umbilical cord and placenta after birth. Cord blood has a higher concentration of HSC (hematopoietic stem cells --ed.) than is normally found in adult blood. However, the small quantity of blood obtained from an umbilical cord (typically about 50 mL) makes it more suitable for transplantation into small children than into adults. Newer techniques using ex-vivo expansion of cord blood units or the use of two cord blood units from different donors are being explored to allow cord blood transplants to be used in adults."
I spent six months in Seattle as a caregiver for a patient undergoing this procedure. The work they do at the Fred Hutchinson Cancer Research Center there is second to none.
2 sets of DNA? (Score:4, Funny)
I see what he did there (Score:2, Funny)
as recalled by the csi tag (Score:5, Interesting)
real but extremely rare, it developmentally consists of nonidentical twins in the womb whose embryos fuse very early on, when that is still possible (when they are only a couple of hundred cells, for example)
then the organism consists of one individual, but one organ system might be a completely different genetic makeup than another organism. so sombody's nervous system could be genetic code A, while his spleen could be genetic code B. chimeras can go through life having no idea what they are, but sometimes, you can see it on their skin (a subtle zebra striping)
Change or add? (Score:5, Insightful)
Re: (Score:3, Informative)
Genetic chimeras and tranplants (Score:5, Informative)
As others have pointed out, this isn't anything new. Significant clinical use of BMT dates back to the 1970's. PBSCT and UCBT came into widespread use in the late 1980's and early 1990's.
My group performed a BMT on a patient with relapsed leukemia a few years ago. The patient unfortunately suffered liver and kidney damage as a result of the BMT. He had a liver transplanted from one donor and later a kidney from another donor. Fortunately, he recovered and has remained leukemia free. He is essentially back to being a normal kid, although he will need to take immunosuppressive mediations to prevent rejection indefinitely. That patient permanently has DNA from 4 different sources (bone marrow, liver, kidney, and his original genotype in all other parts of his body).
The really amazing thing (Score:3, Interesting)
Re: (Score:2)
I first read that as "marijuana"
Re: (Score:2)
Well, yeah. Except, what if they guy who's about to invent a viable preventative for malaria has non-Hodgkins lymphoma?
Re: (Score:2, Redundant)
Re: (Score:2, Informative)
Re: (Score:3, Informative)
Re:This scares the hell out of me. (Score:5, Insightful)
In answer to your question "While this is an amazing break-through what will happen if this guy has offspring?", the answer is nothing. At least, nothing different than if he hadn't had stem cells implanted. For there to be any difference, there would've had to have replaced the spermatogonia.
Parent
Re:This scares the hell out of me. (Score:5, Informative)
If it had been a "traditional" bone marrow transplant, he would STILL have had a second set of DNA found in his blood. This is becasue for this therapy to work, all of his native bone marrow is destroyed, completely. He will be physically incapable of making his own red, white, and platelet cells. The donor donated marrow is then given to him in the hopes that it will "take root" where his now-ablated marrow once was, and will take that function. It's just like a kidney or heart transplant, just much wetter.
As for offspring due to the implanted cells, not gonna happen. The Gonads are very well protected from things like this, and just like with a transplanted solid organ, this only affects the somatic cells, not the germ cells created in his testes.
So, just remember, think of the bone marrow and blood as another organ, and this is just another organ transplant. His biggest concern would be the effects of his chemo and radiation on his gonads, not the transplanted cells. Make sense?
Parent
Re: (Score:2)
Absolutely nothing out of the ordinary. He has different DNA in different cells (and the non-original DNA is in blood cells.)
If he has offspring, each will be produced by exactly one of his cells, which will have one set of (half of) his original DNA.