6 ms·

After a bone marrow transplant, a man has two sets of DNA

108 points by mcenedella 7y ago

philshem 7y ago
> After a bone marrow transplant...
- SlowRobotAhead 7y ago
  RTFA. It’s not unheard of for blood to get the donor’s DNA. But it’s very uncommon to get the donor’s sperm and the other places the donor’s DNA has been found in the guy.
dade_ 7y ago
DNA evidence alone would not convince me beyond a reasonable doubt. If DNA 'positive match' wasn't already being abused as evidence then this would have little impact. DNA should only be used to prove someone is innocent (DNA doesn't match) or support other evidence they are guilty. There are also actual instances of problematic matches noted in the article as well.
- deleted 7y ago
  [deleted]
- wespiser_2018 7y ago
  Yea, but there is definitely a gradient or propensity of evidence that is often lost. For instance, touch transfer DNA can deposit your DNA on a crime scene if you interacted with the EMTs earlier in the day (Anderson case, 2012) [1] which means very little, but if a suspect's fingerprint is in the victim's blood, it's very likely the suspect was present during an attack. In the later case, I think DNA evidence, the victim's in the case, would be evidence of guilt, but needs to be part of a larger, coherent case. [1] https://www.forbes.com/sites/marinamedvin/2018/09/20/framed-by-your-own-cells-how-dna-evidence-imprisons-the-innocent/#101a7f0e4b86 https://www.forbes.com/sites/marinamedvin/2018/09/20/framed-...
buboard 7y ago
we need mass marrow transplants to confuse dna identification systems
fiftyacorn 7y ago
I wonder if we will see this being used in professional sport?
- yorwba 7y ago
  The Finnish skier Eero Mäntyranta probably owed much of his success to his polycythemia, significantly increasing the number of red blood cells and thus the oxygen-carrying capacity of his blood. Since red blood cells are produced in the bone marrow, a transplant could be used to deliberately induce polycythemia. However, a quick search for bone marrow transplants for polycythemia yielded only results about curing the disease with transplants. Probably not a great idea, especially considering it would likely be considered a form of doping and get banned.
- jeffnappi 7y ago
  The procedure to get a bone marrow transplant is horrific. It involves incredibly painful procedures combined with necessary immune system suppression.
  - fiftyacorn 7y ago
    They dont need to get the proceedure - they just need to get a medical record of the procedure. Anyway nothing surprises me the lengths professional athletes will go to to win
  - lrhegeba 7y ago
    just as with blood doping, if an athlete would use his own bone marrow there is no need for immune suppression medication.
new_guy 7y ago
There's been well documented cases of people taking on the personality traits of their donors too, 'who we are' is literally in the DNA. Even something as relatively simple as a blood transfusion contaminates you and can fundamentally change who you are. It's not as well studied or given the visibility it should be because of the obvious implications. [0] https://blogs.unimelb.edu.au/sciencecommunication/2016/10/15/organ-transplants-a-change-of-heart-in-more-ways-than-one/ https://blogs.unimelb.edu.au/sciencecommunication/2016/10/15... [1] https://www.medicaldaily.com/can-organ-transplant-change-recipients-personality-cell-memory-theory-affirms-yes-247498 https://www.medicaldaily.com/can-organ-transplant-change-rec... [2] https://www.ncbi.nlm.nih.gov/pubmed/1299456 https://www.ncbi.nlm.nih.gov/pubmed/1299456 [3] https://listverse.com/2016/05/14/10-organ-recipients-who-took-on-the-traits-of-their-donors/ https://listverse.com/2016/05/14/10-organ-recipients-who-too...
- pergadad 7y ago
  I don't know if there's more to this rabbit hole, but a few self-reported cases (placebo effect?!) and a theory with some gaping holes don't seem to me like "well documented cases". If there are physical changes you can expect some effect on personality - say if a new heart is able to more efficiently transfer blood the patient might find herself more prone to physical activity. Or a better kidney and liver might affect food preferences. New blood type might offer have some wider effect but even that's a still very much questionable field of research. To latch onto the example given in all your links, there are no taste receptors in the heart and neither is there any indication that memories are saved in the heart. Spinal cord - yes, especially if it's about movement. But not in organs like the heart which give much more basic input and have far fewer connections to the rest of the neural network. There is no chicken nugget and beer neutral network linked to the heart - and if there was, chances are any organ transplant would have severed them.
  - perl4ever 7y ago
    It's been suggested that gut microbes affect mental functioning - maybe a surgery/transplant could affect the immune system (not to mention immunosuppressive drugs would be a given, right?) which in turn would affect which microbes thrive, and therefore personality.
jariel 7y ago
There's too much paywalled content here, we don't all have subscriptions to everything, it's getting tiring to click on such links. HN should put a little star or something beside paywalled links, or put the link in a different colour to hint that it's paywalled.
crooked-v 7y ago
Also see natural genetic chimerism, which is extremely rare but not unknown in humans. https://en.wikipedia.org/wiki/Chimera_(genetics)#Humans https://en.wikipedia.org/wiki/Chimera_(genetics)#Humans
- maxerickson 7y ago
  I don't think the prevalence is well understood (situations where it is necessary to prove it out aren't common). I went to school with someone that had different colored eyes, something that is much more common than the discussion at your link.
  - patall 7y ago
    Of course we do not know exacty but there are multiple levels of evidence now that chimerism is very rare. One example would be cancer sequencing were you compare DNA from the cancer to a control tissue. I haven't heard of any of those mentioning any cases. The other case would be the recent GTEx concortia that sequenced upto 40 tissues of 600+ humans and did not detect any obvious chimera cases. Different colored eyes one the other hand my be caused by a lot of things like no-genetic reasons, but also somatic (i.e post egg fertilization) mutations like loss of one chromosome copy and others.
    - perl4ever 7y ago
      What is the probability of a (randomly selected?) control tissue of a "average" chimera having different DNA, though? I have no idea, but intuitively it would make a big difference in what fraction you detect.
- mongol 7y ago
  I read about this a while back, I got the understanding that it is poorly known how rare it is. Many cases have been found by coincidence.
jedberg 7y ago
My friend donated marrow to his brother. We always joke about how his brother can commit crimes willy nilly and then pin it on him, or better yet, they could commit crimes together and get away with it by taking advantage of the doubt that would be introduced by them both having the same DNA.
- perl4ever 7y ago
  There was a case in the news like that, where a pair of twins were implicated, and they tried to argue that since it was impossible to tell which one of them it was, neither could be convicted.
  - PopeDotNinja 7y ago
    Probably makes a better movie than reality. I wouldn't bet my future on that. A prosecutor might jail one arbitrarily by spinning the story the right way.
    - tokai 7y ago
      It did happen in germany. https://www.spiegel.de/international/germany/a-perfect-crime-twins-suspected-in-spectacular-jewelry-heist-set-free-a-614245.html https://www.spiegel.de/international/germany/a-perfect-crime...
    - klyrs 7y ago
      An acquaintance of mine has an identical twin. For a time, they shared a car, and one of them got nabbed by a red-light camera. His face was captured rather faithfully, but not in enough detail to distinguish between the twins. Both showed up to court, both plead the fifth; case closed, no ticket.
  - deleted 7y ago
    [deleted]
Laforet 7y ago
White blood cells frequently infiltrate soft tissues in order to do their duty so it's quite plausible that some donor DNA sequence will be found in other organs. I couldn't seem to find a link to the original report in the linked article however it would not surprise me if some of the forensic techniques replied on testing for mitochondrial DNA as it tends to be better preserved in the natural environment. Human cells are known to exchange mitochondria so mtDNA is more likely to display chimerism, especially in this case where the donor is matched to the recipient.
myrryr 7y ago
Bone marrow makes stem cells. Stem cell become the cells required in different areas in the body. Like, this isn't unexpected.
- eximius 7y ago
  Many things are unexpected in hindsight.
  - myrryr 7y ago
    It may help that I have an ex who was in stem cell research, but I always thought that marrow transplants would make a Chimera. Hell, people were trying to cure HIV based on this. At least for me, this is a TOTAL lack of surprise. I would have been super surprised if it didn't.
chiefalchemist 7y ago
Things like this story, epigenetics, etc. should really have us questioning our understanding of gentics. We don't seem to be as static and unique as we thought. There seems to be more going on here. More yet to be known.
mirimir 7y ago
> The most unexpected part was that four years after the procedure, the DNA in his semen had been entirely replaced by his donor’s. That blew my mind. Because it's my understanding that the germline is too well segregated from somatic tissues. Even stem cells. But then, I see that the patient previously had a vasectomy. So there are arguably no sperm in his semen. And it's not surprising that the donor's stem cells have replaced his prostate etc.
known 7y ago
Sounds like https://en.wikipedia.org/wiki/Chimera_(genetics) https://en.wikipedia.org/wiki/Chimera_(genetics)

108 points by mcenedella 7y ago

philshem 7y ago

> After a bone marrow transplant...

SlowRobotAhead 7y ago
RTFA. It’s not unheard of for blood to get the donor’s DNA. But it’s very uncommon to get the donor’s sperm and the other places the donor’s DNA has been found in the guy.

dade_ 7y ago

DNA evidence alone would not convince me beyond a reasonable doubt. If DNA 'positive match' wasn't already being abused as evidence then this would have little impact. DNA should only be used to prove someone is innocent (DNA doesn't match) or support other evidence they are guilty. There are also actual instances of problematic matches noted in the article as well.

deleted 7y ago
[deleted]
wespiser_2018 7y ago
Yea, but there is definitely a gradient or propensity of evidence that is often lost. For instance, touch transfer DNA can deposit your DNA on a crime scene if you interacted with the EMTs earlier in the day (Anderson case, 2012) [1] which means very little, but if a suspect's fingerprint is in the victim's blood, it's very likely the suspect was present during an attack. In the later case, I think DNA evidence, the victim's in the case, would be evidence of guilt, but needs to be part of a larger, coherent case. [1] https://www.forbes.com/sites/marinamedvin/2018/09/20/framed-by-your-own-cells-how-dna-evidence-imprisons-the-innocent/#101a7f0e4b86 https://www.forbes.com/sites/marinamedvin/2018/09/20/framed-...

buboard 7y ago

we need mass marrow transplants to confuse dna identification systems

fiftyacorn 7y ago

I wonder if we will see this being used in professional sport?

yorwba 7y ago
The Finnish skier Eero Mäntyranta probably owed much of his success to his polycythemia, significantly increasing the number of red blood cells and thus the oxygen-carrying capacity of his blood. Since red blood cells are produced in the bone marrow, a transplant could be used to deliberately induce polycythemia. However, a quick search for bone marrow transplants for polycythemia yielded only results about curing the disease with transplants. Probably not a great idea, especially considering it would likely be considered a form of doping and get banned.
jeffnappi 7y ago
The procedure to get a bone marrow transplant is horrific. It involves incredibly painful procedures combined with necessary immune system suppression.
- fiftyacorn 7y ago
  They dont need to get the proceedure - they just need to get a medical record of the procedure. Anyway nothing surprises me the lengths professional athletes will go to to win
- lrhegeba 7y ago
  just as with blood doping, if an athlete would use his own bone marrow there is no need for immune suppression medication.

new_guy 7y ago

There's been well documented cases of people taking on the personality traits of their donors too, 'who we are' is literally in the DNA. Even something as relatively simple as a blood transfusion contaminates you and can fundamentally change who you are. It's not as well studied or given the visibility it should be because of the obvious implications. [0] https://blogs.unimelb.edu.au/sciencecommunication/2016/10/15/organ-transplants-a-change-of-heart-in-more-ways-than-one/ https://blogs.unimelb.edu.au/sciencecommunication/2016/10/15... [1] https://www.medicaldaily.com/can-organ-transplant-change-recipients-personality-cell-memory-theory-affirms-yes-247498 https://www.medicaldaily.com/can-organ-transplant-change-rec... [2] https://www.ncbi.nlm.nih.gov/pubmed/1299456 https://www.ncbi.nlm.nih.gov/pubmed/1299456 [3] https://listverse.com/2016/05/14/10-organ-recipients-who-took-on-the-traits-of-their-donors/ https://listverse.com/2016/05/14/10-organ-recipients-who-too...

pergadad 7y ago
I don't know if there's more to this rabbit hole, but a few self-reported cases (placebo effect?!) and a theory with some gaping holes don't seem to me like "well documented cases". If there are physical changes you can expect some effect on personality - say if a new heart is able to more efficiently transfer blood the patient might find herself more prone to physical activity. Or a better kidney and liver might affect food preferences. New blood type might offer have some wider effect but even that's a still very much questionable field of research. To latch onto the example given in all your links, there are no taste receptors in the heart and neither is there any indication that memories are saved in the heart. Spinal cord - yes, especially if it's about movement. But not in organs like the heart which give much more basic input and have far fewer connections to the rest of the neural network. There is no chicken nugget and beer neutral network linked to the heart - and if there was, chances are any organ transplant would have severed them.
- perl4ever 7y ago
  It's been suggested that gut microbes affect mental functioning - maybe a surgery/transplant could affect the immune system (not to mention immunosuppressive drugs would be a given, right?) which in turn would affect which microbes thrive, and therefore personality.

jariel 7y ago

There's too much paywalled content here, we don't all have subscriptions to everything, it's getting tiring to click on such links. HN should put a little star or something beside paywalled links, or put the link in a different colour to hint that it's paywalled.

crooked-v 7y ago

Also see natural genetic chimerism, which is extremely rare but not unknown in humans. https://en.wikipedia.org/wiki/Chimera_(genetics)#Humans https://en.wikipedia.org/wiki/Chimera_(genetics)#Humans

maxerickson 7y ago
I don't think the prevalence is well understood (situations where it is necessary to prove it out aren't common). I went to school with someone that had different colored eyes, something that is much more common than the discussion at your link.
- patall 7y ago
  Of course we do not know exacty but there are multiple levels of evidence now that chimerism is very rare. One example would be cancer sequencing were you compare DNA from the cancer to a control tissue. I haven't heard of any of those mentioning any cases. The other case would be the recent GTEx concortia that sequenced upto 40 tissues of 600+ humans and did not detect any obvious chimera cases. Different colored eyes one the other hand my be caused by a lot of things like no-genetic reasons, but also somatic (i.e post egg fertilization) mutations like loss of one chromosome copy and others.
  - perl4ever 7y ago
    What is the probability of a (randomly selected?) control tissue of a "average" chimera having different DNA, though? I have no idea, but intuitively it would make a big difference in what fraction you detect.
mongol 7y ago
I read about this a while back, I got the understanding that it is poorly known how rare it is. Many cases have been found by coincidence.

jedberg 7y ago

My friend donated marrow to his brother. We always joke about how his brother can commit crimes willy nilly and then pin it on him, or better yet, they could commit crimes together and get away with it by taking advantage of the doubt that would be introduced by them both having the same DNA.

perl4ever 7y ago
There was a case in the news like that, where a pair of twins were implicated, and they tried to argue that since it was impossible to tell which one of them it was, neither could be convicted.
- PopeDotNinja 7y ago
  Probably makes a better movie than reality. I wouldn't bet my future on that. A prosecutor might jail one arbitrarily by spinning the story the right way.
  - tokai 7y ago
    It did happen in germany. https://www.spiegel.de/international/germany/a-perfect-crime-twins-suspected-in-spectacular-jewelry-heist-set-free-a-614245.html https://www.spiegel.de/international/germany/a-perfect-crime...
  - klyrs 7y ago
    An acquaintance of mine has an identical twin. For a time, they shared a car, and one of them got nabbed by a red-light camera. His face was captured rather faithfully, but not in enough detail to distinguish between the twins. Both showed up to court, both plead the fifth; case closed, no ticket.
- deleted 7y ago
  [deleted]

Laforet 7y ago

White blood cells frequently infiltrate soft tissues in order to do their duty so it's quite plausible that some donor DNA sequence will be found in other organs. I couldn't seem to find a link to the original report in the linked article however it would not surprise me if some of the forensic techniques replied on testing for mitochondrial DNA as it tends to be better preserved in the natural environment. Human cells are known to exchange mitochondria so mtDNA is more likely to display chimerism, especially in this case where the donor is matched to the recipient.

myrryr 7y ago

Bone marrow makes stem cells. Stem cell become the cells required in different areas in the body. Like, this isn't unexpected.

eximius 7y ago
Many things are unexpected in hindsight.
- myrryr 7y ago
  It may help that I have an ex who was in stem cell research, but I always thought that marrow transplants would make a Chimera. Hell, people were trying to cure HIV based on this. At least for me, this is a TOTAL lack of surprise. I would have been super surprised if it didn't.

chiefalchemist 7y ago

Things like this story, epigenetics, etc. should really have us questioning our understanding of gentics. We don't seem to be as static and unique as we thought. There seems to be more going on here. More yet to be known.

mirimir 7y ago

> The most unexpected part was that four years after the procedure, the DNA in his semen had been entirely replaced by his donor’s. That blew my mind. Because it's my understanding that the germline is too well segregated from somatic tissues. Even stem cells. But then, I see that the patient previously had a vasectomy. So there are arguably no sperm in his semen. And it's not surprising that the donor's stem cells have replaced his prostate etc.

known 7y ago

Sounds like https://en.wikipedia.org/wiki/Chimera_(genetics) https://en.wikipedia.org/wiki/Chimera_(genetics)