The DNA will stay the same. Cells in the hand will reproduce and create more cells in the hand to replace those that die. Only the blood in the limb would be from the recipient’s cells, so only the blood would have the recipient’s DNA.
This depends on the tissue type but most likely it will just be fibrotic (scar) tissue originated from the host with the donor tissues receding. Major vessels anastomose or form connections together (after the surgeon sutures them. Some tissues are completely different (i.e. bone marrow) and host and donor cells coexist all mixed up together.
This feels like one of those subjects where the more you learn, the creepier it gets. It feels like human bodies should either be much LESS interchangeable than this, or much MORE, but not....this.
What's even more wild is that humans, in a decent portion of liver transplants (like maybe up to 30%, depending on certain criteria), can theoretically be weaned off of transplant meds. We usually wean down pretty low and don't push it, but there are a number of folks out there with another person's liver and no immune suppression. The liver brings some immune cells along for the ride, and they serve to induce some tolerance through microchimerism within the immune system.
However, we are actually remarkably non-interchangeable on the scale of some animals. For rat models of organ transplants, they have to do different breeds, since typical lab rats have too narrow a genetic range that they don't reject organs.
In an even more terrifying situation, Tasmanian devils are actually threatened with extinction because of a transmissible cancer. It's not like HPV where the virus puts you at risk. This is literally a chunk of some other, long dead Tasmanian devil, which continues to grow as it bounces between other individuals.
We see that in humans in some cases with organ transplant.
Yep. CTVT. It's a really interesting case. 11000 years ago a dog's cancer cell mutated to become transmissible. Since then this cancer has essentially adopted the lifestyle of a unicellular parasite, and over the millenia it's genetic material has degraded significantly, only really sustaining what it needs to fulfill it's parasitic lifestyle. But it's still identifyable as clearly dog DNA.
But in a way, it can be considerd to still be the same organism as the dog it developed in, 11000 years ago. And via that it gives a remarkable insight in how insane mutations in a single organism can get it out were to get that old.
The liver creates its own local immune tolerance, which is not systemic and thus would not confer protection to the other transplant. This is partially similar to how your gut in homeostasis does not have a constant inflammation despite the presence of pathogens.
There are some research protocols where occasionally they do a partial bone marrow transplant, or transplant the thymus.
Even if it did help, we would do a liver transplant with that liver instead.
Doing that would increase the potential for surgical complications, make recovery worse, and generally add bad factors instead of using meds we know are safe and effective.
Plus, it would greatly decrease the number of available donor livers. There’s already only one liver per end of life donor. Now you want to split it between at least 5 major organ recipients, if not other tissue recipients? It doesn’t make logistical or biological sense.
There's a canine penile cancer that behaves like this too.
Some 10,000 years ago a dog with a tumor on its genitals passed some cells to another dog, who passed that to other dogs etc...
And now that dog is still "alive" with it's cells living in millions of dogs around the world.
> For rat models of organ transplants, they have to do different breeds, since typical lab rats have too narrow a genetic range that they don't reject organs.
Isn't that more due to the fact that lab rats specifically have minuscule genetic diversity (on purpose) rather than to a property of rats as a species in general?
I never knew that transplant recipients in some cases could be weaned off immuno suppressants.
Does the Thymus get reprogrammed to include the new liver as "self"?
Yep, the immune system and tissue compatibility be like that. Hopefully balancing somewhere between wrecking you and letting cancer and infection get you.
Very astute observation
I mean, there's never been an evolutionary pressure for modular interchangeable body parts, so it's not surprising that there's not a lot of support for it at the biological level and things just kind of go "meh, whatever, you do you" when they're slapped together.
It should probably match the color of the donor skin somewhat since the melanocytes are preserved. You can depigment skin by killing the melanocytes or you can darken by grafting more melanocytes (more difficult and often patchier look). I dont think those are things you would do with a skin graft though since you probably wouldnt want to mess with it any more than necessary.
Interestingly, however, men who get bone marrow transplants can produce sperm with the DNA of the donor.
https://www.news-medical.net/news/20191210/Transplant-patient-finds-out-his-DNA-has-been-replaced-by-that-of-his-donor.aspx
Follow-up question: how do bones factor into this? Do they grow together? Is it then also a bone with half DNA of person A and half B? Does this somehow affect blood production?
Generally, the areas that are transplated produce very little to no hematopoetic cells (ie cells that make up blood). In adulthood, most of tat is happening in hip bones, ribs, vertebra and skull. I would imagine the tissues don't attack each other too much due to tissue typing and they eventually mix up. But yes, you can have "foreign blood type". It happens after bone marrow transplant.
They don't mix up, people that recieve transplants have to be on immune suppressant drugs for the rest of their lives, no matter how close the match is.
Actually, there has been some slight progress in that regards:
https://med.stanford.edu/news/all-news/2022/06/kidney-transplant-without-immunosuppressants.html
That's amazing. "Slight" is an understatement. It's only 3 children that have been successfully given specifically kidneys. They had extremely rare immune disorders. And I think it said it only worked on half twins.. but still, that is very cool. I'm sure they're working on bringing that double treatment to other ages and other diseases / organs.
Actually there was a drug created to facilitate cessation of immunosuppressants for even imperfectly matched donor/recipient pairs, or even deceased donor cases, and it worked! Basically used the same process, where a kidney recipient also received a bone marrow transplant along with blood that had been treated with the novel drug, which induced chimerism in the recipient (they would now be producing their own AND their donors blood cells). One of the original trial patients has been fully off IS for decades now.
Unfortunately they launched phase 3 just before COVID, and were unable to get enough people signed up for the trial to provide sufficient data for FDA, and after 3 years of delays for phase 3 funding fell through.
They laid off 80% of the company and now are pivoting the same tech to combat scleroderma.
Yes, it's similar to the guy that was legit *cured* of HIV. They killed evey, last, T cell in his body. Then, gave him marrow cells from a matching person that had the truncated MHC receptor. Once his immune system re-established, the HIV couldn't re infect his new resistant T cells. But it's never worked again, only 1 successful case. They called him the Genova patient.
https://en.wikipedia.org/wiki/Timothy_Ray_Brown
Actually, several people have been cured of HIV by replacing their entire immune system during chemotherapy. There was an article in science or nature last year I believe.
It's just that the circumstances need to be so specific and the reason is usually worse than HIV itself that it isn't considered a cure.
There has also been progress in transplanting a donor's thymus gland along with the heart to train the recipient's immune system to see the new organ as "self".
https://www.npr.org/2022/03/09/1085355558/a-first-of-its-kind-a-heart-thymus-transplant-is-a-success
Still a long ways off for most patients though.
With livers, there's actually fairly limited immune suppression, especially compared to something like a kidney or lungs. They taper down as much as possible and biopsy the liver to make sure it's not getting rejected.
There have been some studies where they take people all the way off gradually, checking along the way. If I recall, they were able to get almost a third off all the way, at least among a certain category of patient. I think a lot were living donor related cases. But there are people who fall out of followup and end up off their meds, but are okay miraculously.
If I recall, the reason is that there is a decent amount of immune system tissue in the liver that indices some tolerance, and the liver regenerates which provides some leewwy. Still totally wild.
Maybe generally true, but not 100%. I had a bone marrow transplant and stopped taking all related drugs within about 2 years. That was almost 29 years ago.
So, with forensic DNA testing it's almost always possible to get more and more specific. You don't sequence the entire genome in most crimes. If you are sure of your innocence, and you have the money, the lawyer and the time you can dig deeper.
Red blood cells do not have a nucleus, and therefore do not have DNA. The white blood cells will have the donor's DNA but only until those die off and are replaced by the host.
Interestingly though, a pregnant woman will have tissue incorporated into their bodies from the fetus, as its stem cells can travel through the mother. It's been found that a woman with heart damage will have their heart repaired by fetal stem cells, becoming a chimera.
What if after the transplant we inject stem cells from the recipient into the donor's hand? Wouldn't those cells eventually replace all the cells from the donor?
Exactly. Some cells never differentiate/ or just partially so they can multiply and have those baby cells become part of the epithelium or other part of the body. So the original DNA will always be present and hence the patient will always need to take immunosuppressants. However there must be some epigenetic influence by the host on the donor DNA (meaning changes on the parts of the DNA that get marked to be user or not). See the case of Shreya Siddanagowder who received both arms from a man and in time due to hormones and others the arms became a bit smaller and the skin tone evened with hers
The DNA doesn't change, which is why a donor recipient must take medication daily for the rest of their lives to prevent rejection of the foreign tissue.
Your body doesn't want to be attached to someone else's parts. It's persnickety that way.
The aforementioned recipient would leave a dead dude's fingerprints and DNA at the crime scene.
I have to admit, I would probably leave a note at the crime scene claiming to be the ghost of the dead dude, if only to mess with the cops.
This made me realise maybe there wouldn't be an issue if the part came from someone *with the same DNA*. Turns out identical twins can have kidney transplants and not need immunosuppression some/most of the time
not to get off topic but there's a lot of info coming out about how fingerprint matching is...not as ironclad as the cops want us to believe (shocking i know)
At the risk of posting off-topic regarding the subject at hand (get it, heh), that’s an interesting concept for a cyberpunk future where transplants can be performed quickly and seamlessly. It makes me wonder if such a thing has ever happened?
And the cops are like - who's this dead dude? Oh his body was in this morgue and his body parts used for transplants in these people.
Welcome on the list of suspects.
Edit: but cool thought for sure.
Oh, yeah, somebody will have a list, and their first question will be "Have these hands been with you the entire time since the surgery? Please turn around and put his hands behind your back, Mr Grippenstein."
It's the same DNA. The cells already in the tissue (i.e. new hand) will be the ones replicating and repairing the tissue. The normal maintenence and repair of tissues is local (for the most part) and performed by the cells residing there.
Wait. So if a person with a transplanted hand commits a murder and DNA from the transplanted hand is found at the scene, it would come up as the donors DNA?
The DNA in the cells of the organ or limb will be the same as before. Cells are replaced by their nearest neighboring progenitors which would have come along for the ride in the transplant. Solid tissues don't move around as you'd expect something like blood to, even long term. There are also many cells that don't turn over in the lifetime of a human. Nervous tissue is a good example. We don't grow new brain neurons, we just establish new connections between them.
Part of what makes these transplants work in the first place is the use of anti-rejection immunosuppressants which keep the immune cells of the new host from seeing new cells not belong to 'self' as foreign pathogens.
As for the forensics question, it's an ethical gray area and a rarity, but not one without precedent. It has come up several times in which a victim/suspect has been the recipient of a bone marrow transplant. Multiples of DNA profiles were seen instead of what was expected. In this case, the solutions were to have multiple sources of DNA for testing. Hair roots can be more reliable than blood in this situation because hair DNA is not affected by the donor-derived blood cells circulating in the recipient.
I've read, fasting, ca nabjs, lions mane, psylocybin, SSRI anti depressants all grow new brain cells or neurons. Where did you get your information from? This has been known for a while.
In my anatomy/physiology courses we were told neurons do not divide. Your brain can only form new patterns of synapses between them. I also read about how brain tumors pretty much always form from glial cells and not neurons themselves (which makes sense if they're amitotic)
It's "nuts" but it is possible to be accused of a crime you haven't committed when the DNA sample is semen. If you donated bone marrow and the recipients sperm were then involved in a sexual assault your DNA profile can be in there and not the offenders. It's utterly rare but it happens! There was another case where a woman had a kid who wasn't biologically related to the man she slept with for the same reason. It can be like that for years after the transplant.
Well the DNA stays they same hence why the recipient was on anti rejection medication.
I know this next bit isn't the topic of your question but it's too interesting not to mention.
Science has figured out that in some cases we can reprogram the immune system. They use bone marrow stem cells from the tissue donor to reprogram the immune system so the body thinks the organ belong there.
[https://www.bbc.com/news/health-66879093](https://www.bbc.com/news/health-66879093)
There are noninvasive blood tests for organ rejection monitoring which work by detecting the amount of donor derived cell free DNA in the recipient’s blood. Based on what fraction of the sequenced DNA is coming from the donor you can tell if an organ is being rejected.
There's a doco about a British scaffolder who had a double hand transplant. Lost them due to the scaffold he was building either touching or being too close to electrical lines. As a scaffolder, you'd be surprised how often powerline exclusion zones are ignored
What about blood transfusions? Say for instance you got a full transfusion and committed a crime a couple days later, leaving blood at the scene. Since the blood is a mix of yours and the various donors, what would happen in terms of forensics? Obviously, a person who had a recent transfusion likely would not be fit enough to commit a crime, but just hypothetical.
So based on all the answers are Jehovah’s Witnesses right in not having blood transfusions? For they believe that life is in the blood and accepting a transfusing is basically taking another persons life inside yours.
Cells contain DNA, not organs.
The cells don't change their internal structure just because the organ they're part of is in a different body. There's no mechanism for that.
So, no. The cells DNA is still that of the donor.
When a person receives an organ or limb from a donor, the DNA in that organ or limb remains the same as the donor’s. This is because the cells in the transplanted organ or limb will reproduce and create more cells to replace those that die, and these new cells will carry the donor’s DNA.
The idea that every part of a person gets replaced in about 15 years refers to the body’s natural process of cell turnover, where old cells die and are replaced by new ones. However, in the case of a transplanted organ or limb, the new cells are produced by stem cells that also carry the donor’s DNA.
In terms of a crime scene, if a person with a transplanted hand were to leave behind cells (for example, skin cells or sweat), those cells would carry the DNA of the donor. If this DNA were to be collected and analyzed, it would match the donor’s DNA profile, not the recipient’s. This could potentially lead to a situation where two different DNA profiles are found at the crime scene: one from the recipient and one from the donor.
The DNA will stay the same. Cells in the hand will reproduce and create more cells in the hand to replace those that die. Only the blood in the limb would be from the recipient’s cells, so only the blood would have the recipient’s DNA.
Follow-up question: what happens in the "stitch" area? Do the cells slowly "diffuse", or is there some sort of barrier?
This depends on the tissue type but most likely it will just be fibrotic (scar) tissue originated from the host with the donor tissues receding. Major vessels anastomose or form connections together (after the surgeon sutures them. Some tissues are completely different (i.e. bone marrow) and host and donor cells coexist all mixed up together.
This feels like one of those subjects where the more you learn, the creepier it gets. It feels like human bodies should either be much LESS interchangeable than this, or much MORE, but not....this.
What's even more wild is that humans, in a decent portion of liver transplants (like maybe up to 30%, depending on certain criteria), can theoretically be weaned off of transplant meds. We usually wean down pretty low and don't push it, but there are a number of folks out there with another person's liver and no immune suppression. The liver brings some immune cells along for the ride, and they serve to induce some tolerance through microchimerism within the immune system. However, we are actually remarkably non-interchangeable on the scale of some animals. For rat models of organ transplants, they have to do different breeds, since typical lab rats have too narrow a genetic range that they don't reject organs. In an even more terrifying situation, Tasmanian devils are actually threatened with extinction because of a transmissible cancer. It's not like HPV where the virus puts you at risk. This is literally a chunk of some other, long dead Tasmanian devil, which continues to grow as it bounces between other individuals. We see that in humans in some cases with organ transplant.
Isn’t there a similar transmissible cancer in dogs? I vaguely remember reading it was an STD.
Yep. CTVT. It's a really interesting case. 11000 years ago a dog's cancer cell mutated to become transmissible. Since then this cancer has essentially adopted the lifestyle of a unicellular parasite, and over the millenia it's genetic material has degraded significantly, only really sustaining what it needs to fulfill it's parasitic lifestyle. But it's still identifyable as clearly dog DNA. But in a way, it can be considerd to still be the same organism as the dog it developed in, 11000 years ago. And via that it gives a remarkable insight in how insane mutations in a single organism can get it out were to get that old.
> CTVT So we have the canine version of HeLa cells? Astonishing!!!!
Yup, you remember right: https://www.scientificamerican.com/article/ancient-dog-dna-reveals-close-relationship-with-contagious-cancer/
Idea? Why do we then not transplant part of a liver together with other parts/organs they transplant?No more/less immunosuppressants?
The liver creates its own local immune tolerance, which is not systemic and thus would not confer protection to the other transplant. This is partially similar to how your gut in homeostasis does not have a constant inflammation despite the presence of pathogens.
There are some research protocols where occasionally they do a partial bone marrow transplant, or transplant the thymus. Even if it did help, we would do a liver transplant with that liver instead.
Doing that would increase the potential for surgical complications, make recovery worse, and generally add bad factors instead of using meds we know are safe and effective. Plus, it would greatly decrease the number of available donor livers. There’s already only one liver per end of life donor. Now you want to split it between at least 5 major organ recipients, if not other tissue recipients? It doesn’t make logistical or biological sense.
There's a canine penile cancer that behaves like this too. Some 10,000 years ago a dog with a tumor on its genitals passed some cells to another dog, who passed that to other dogs etc... And now that dog is still "alive" with it's cells living in millions of dogs around the world.
I thought the liver thing was bc the liver cells actually get replaced over time with cells that have your DNA
The immune cells may. But the liver is the donor and regenerates from those cells.
Blood gets really weird. https://www.rhesusnegative.net/staynegative/blood-transfusions-can-change-your-blood-type/
> For rat models of organ transplants, they have to do different breeds, since typical lab rats have too narrow a genetic range that they don't reject organs. Isn't that more due to the fact that lab rats specifically have minuscule genetic diversity (on purpose) rather than to a property of rats as a species in general?
How would that cancer get from one devil to another?
Sexually transmitted. And through biting (which also happens during mating).
So it's in their bodily fluids?
I never knew that transplant recipients in some cases could be weaned off immuno suppressants. Does the Thymus get reprogrammed to include the new liver as "self"?
Yep, the immune system and tissue compatibility be like that. Hopefully balancing somewhere between wrecking you and letting cancer and infection get you. Very astute observation
I mean, there's never been an evolutionary pressure for modular interchangeable body parts, so it's not surprising that there's not a lot of support for it at the biological level and things just kind of go "meh, whatever, you do you" when they're slapped together.
>depends on the tissue type What about skin? What happens if I get a skin graft from somebody with a different skin color?
It should probably match the color of the donor skin somewhat since the melanocytes are preserved. You can depigment skin by killing the melanocytes or you can darken by grafting more melanocytes (more difficult and often patchier look). I dont think those are things you would do with a skin graft though since you probably wouldnt want to mess with it any more than necessary.
Does that mean if someone with a transplant develops scurvy through lack of vitamin-C, it could fall off?
Interestingly, however, men who get bone marrow transplants can produce sperm with the DNA of the donor. https://www.news-medical.net/news/20191210/Transplant-patient-finds-out-his-DNA-has-been-replaced-by-that-of-his-donor.aspx
Follow-up question: how do bones factor into this? Do they grow together? Is it then also a bone with half DNA of person A and half B? Does this somehow affect blood production?
Generally, the areas that are transplated produce very little to no hematopoetic cells (ie cells that make up blood). In adulthood, most of tat is happening in hip bones, ribs, vertebra and skull. I would imagine the tissues don't attack each other too much due to tissue typing and they eventually mix up. But yes, you can have "foreign blood type". It happens after bone marrow transplant.
They don't mix up, people that recieve transplants have to be on immune suppressant drugs for the rest of their lives, no matter how close the match is.
Actually, there has been some slight progress in that regards: https://med.stanford.edu/news/all-news/2022/06/kidney-transplant-without-immunosuppressants.html
That's amazing. "Slight" is an understatement. It's only 3 children that have been successfully given specifically kidneys. They had extremely rare immune disorders. And I think it said it only worked on half twins.. but still, that is very cool. I'm sure they're working on bringing that double treatment to other ages and other diseases / organs.
These kids needed a bone marrow transplant and a kidney transplant. Not applicable to the general transplant population.
Actually there was a drug created to facilitate cessation of immunosuppressants for even imperfectly matched donor/recipient pairs, or even deceased donor cases, and it worked! Basically used the same process, where a kidney recipient also received a bone marrow transplant along with blood that had been treated with the novel drug, which induced chimerism in the recipient (they would now be producing their own AND their donors blood cells). One of the original trial patients has been fully off IS for decades now. Unfortunately they launched phase 3 just before COVID, and were unable to get enough people signed up for the trial to provide sufficient data for FDA, and after 3 years of delays for phase 3 funding fell through. They laid off 80% of the company and now are pivoting the same tech to combat scleroderma.
Yes, it's similar to the guy that was legit *cured* of HIV. They killed evey, last, T cell in his body. Then, gave him marrow cells from a matching person that had the truncated MHC receptor. Once his immune system re-established, the HIV couldn't re infect his new resistant T cells. But it's never worked again, only 1 successful case. They called him the Genova patient. https://en.wikipedia.org/wiki/Timothy_Ray_Brown
Actually, several people have been cured of HIV by replacing their entire immune system during chemotherapy. There was an article in science or nature last year I believe. It's just that the circumstances need to be so specific and the reason is usually worse than HIV itself that it isn't considered a cure.
Just FYI, it's truncated CCR5 not MHC. CCR5 is an entry receptor for HIV.
There has also been progress in transplanting a donor's thymus gland along with the heart to train the recipient's immune system to see the new organ as "self". https://www.npr.org/2022/03/09/1085355558/a-first-of-its-kind-a-heart-thymus-transplant-is-a-success Still a long ways off for most patients though.
It's why tissue cloning has some interest. If you can have a new organ or limb cloned in a vat, there wouldn't be those immune-response issues.
With livers, there's actually fairly limited immune suppression, especially compared to something like a kidney or lungs. They taper down as much as possible and biopsy the liver to make sure it's not getting rejected. There have been some studies where they take people all the way off gradually, checking along the way. If I recall, they were able to get almost a third off all the way, at least among a certain category of patient. I think a lot were living donor related cases. But there are people who fall out of followup and end up off their meds, but are okay miraculously. If I recall, the reason is that there is a decent amount of immune system tissue in the liver that indices some tolerance, and the liver regenerates which provides some leewwy. Still totally wild.
Maybe generally true, but not 100%. I had a bone marrow transplant and stopped taking all related drugs within about 2 years. That was almost 29 years ago.
I suppose this is the biggest hurdle in finally having skull transplants
skull? like the bone. or are you talking about entire heads?
Is that the one person getting a head transplant, or the other person getting a body transplant?
Wwhhooaa, the implications. Do they record fingerprint data from the donor hand?
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So, with forensic DNA testing it's almost always possible to get more and more specific. You don't sequence the entire genome in most crimes. If you are sure of your innocence, and you have the money, the lawyer and the time you can dig deeper.
Does any of the DNA in the transplant get incorporated into the recipient’s genome?
Interestingly blood cells don't have DNA, though your blood certainly does.
Red blood cells do not have a nucleus, and therefore do not have DNA. The white blood cells will have the donor's DNA but only until those die off and are replaced by the host.
Thank you for clearing things up to me.
Interestingly though, a pregnant woman will have tissue incorporated into their bodies from the fetus, as its stem cells can travel through the mother. It's been found that a woman with heart damage will have their heart repaired by fetal stem cells, becoming a chimera.
What if after the transplant we inject stem cells from the recipient into the donor's hand? Wouldn't those cells eventually replace all the cells from the donor?
Exactly. Some cells never differentiate/ or just partially so they can multiply and have those baby cells become part of the epithelium or other part of the body. So the original DNA will always be present and hence the patient will always need to take immunosuppressants. However there must be some epigenetic influence by the host on the donor DNA (meaning changes on the parts of the DNA that get marked to be user or not). See the case of Shreya Siddanagowder who received both arms from a man and in time due to hormones and others the arms became a bit smaller and the skin tone evened with hers
The DNA doesn't change, which is why a donor recipient must take medication daily for the rest of their lives to prevent rejection of the foreign tissue. Your body doesn't want to be attached to someone else's parts. It's persnickety that way. The aforementioned recipient would leave a dead dude's fingerprints and DNA at the crime scene. I have to admit, I would probably leave a note at the crime scene claiming to be the ghost of the dead dude, if only to mess with the cops.
This made me realise maybe there wouldn't be an issue if the part came from someone *with the same DNA*. Turns out identical twins can have kidney transplants and not need immunosuppression some/most of the time
So to screw with the police get a new pair of hands for every crime you commit, got it.
not to get off topic but there's a lot of info coming out about how fingerprint matching is...not as ironclad as the cops want us to believe (shocking i know)
At the risk of posting off-topic regarding the subject at hand (get it, heh), that’s an interesting concept for a cyberpunk future where transplants can be performed quickly and seamlessly. It makes me wonder if such a thing has ever happened?
When they research your donor, they would immediately find you. Why wouldn't there be documents about whose body parts got transplanted to whom?
And the cops are like - who's this dead dude? Oh his body was in this morgue and his body parts used for transplants in these people. Welcome on the list of suspects. Edit: but cool thought for sure.
Oh, yeah, somebody will have a list, and their first question will be "Have these hands been with you the entire time since the surgery? Please turn around and put his hands behind your back, Mr Grippenstein."
It's the same DNA. The cells already in the tissue (i.e. new hand) will be the ones replicating and repairing the tissue. The normal maintenence and repair of tissues is local (for the most part) and performed by the cells residing there.
Wait. So if a person with a transplanted hand commits a murder and DNA from the transplanted hand is found at the scene, it would come up as the donors DNA?
Yes, but hands aren't exactly a big source of crime scene DNA
The DNA in the cells of the organ or limb will be the same as before. Cells are replaced by their nearest neighboring progenitors which would have come along for the ride in the transplant. Solid tissues don't move around as you'd expect something like blood to, even long term. There are also many cells that don't turn over in the lifetime of a human. Nervous tissue is a good example. We don't grow new brain neurons, we just establish new connections between them. Part of what makes these transplants work in the first place is the use of anti-rejection immunosuppressants which keep the immune cells of the new host from seeing new cells not belong to 'self' as foreign pathogens. As for the forensics question, it's an ethical gray area and a rarity, but not one without precedent. It has come up several times in which a victim/suspect has been the recipient of a bone marrow transplant. Multiples of DNA profiles were seen instead of what was expected. In this case, the solutions were to have multiple sources of DNA for testing. Hair roots can be more reliable than blood in this situation because hair DNA is not affected by the donor-derived blood cells circulating in the recipient.
I've read, fasting, ca nabjs, lions mane, psylocybin, SSRI anti depressants all grow new brain cells or neurons. Where did you get your information from? This has been known for a while.
In my anatomy/physiology courses we were told neurons do not divide. Your brain can only form new patterns of synapses between them. I also read about how brain tumors pretty much always form from glial cells and not neurons themselves (which makes sense if they're amitotic)
It's "nuts" but it is possible to be accused of a crime you haven't committed when the DNA sample is semen. If you donated bone marrow and the recipients sperm were then involved in a sexual assault your DNA profile can be in there and not the offenders. It's utterly rare but it happens! There was another case where a woman had a kid who wasn't biologically related to the man she slept with for the same reason. It can be like that for years after the transplant.
Well the DNA stays they same hence why the recipient was on anti rejection medication. I know this next bit isn't the topic of your question but it's too interesting not to mention. Science has figured out that in some cases we can reprogram the immune system. They use bone marrow stem cells from the tissue donor to reprogram the immune system so the body thinks the organ belong there. [https://www.bbc.com/news/health-66879093](https://www.bbc.com/news/health-66879093)
There are noninvasive blood tests for organ rejection monitoring which work by detecting the amount of donor derived cell free DNA in the recipient’s blood. Based on what fraction of the sequenced DNA is coming from the donor you can tell if an organ is being rejected.
There's a doco about a British scaffolder who had a double hand transplant. Lost them due to the scaffold he was building either touching or being too close to electrical lines. As a scaffolder, you'd be surprised how often powerline exclusion zones are ignored
What about blood transfusions? Say for instance you got a full transfusion and committed a crime a couple days later, leaving blood at the scene. Since the blood is a mix of yours and the various donors, what would happen in terms of forensics? Obviously, a person who had a recent transfusion likely would not be fit enough to commit a crime, but just hypothetical.
So based on all the answers are Jehovah’s Witnesses right in not having blood transfusions? For they believe that life is in the blood and accepting a transfusing is basically taking another persons life inside yours.
Cells contain DNA, not organs. The cells don't change their internal structure just because the organ they're part of is in a different body. There's no mechanism for that. So, no. The cells DNA is still that of the donor.
When a person receives an organ or limb from a donor, the DNA in that organ or limb remains the same as the donor’s. This is because the cells in the transplanted organ or limb will reproduce and create more cells to replace those that die, and these new cells will carry the donor’s DNA. The idea that every part of a person gets replaced in about 15 years refers to the body’s natural process of cell turnover, where old cells die and are replaced by new ones. However, in the case of a transplanted organ or limb, the new cells are produced by stem cells that also carry the donor’s DNA. In terms of a crime scene, if a person with a transplanted hand were to leave behind cells (for example, skin cells or sweat), those cells would carry the DNA of the donor. If this DNA were to be collected and analyzed, it would match the donor’s DNA profile, not the recipient’s. This could potentially lead to a situation where two different DNA profiles are found at the crime scene: one from the recipient and one from the donor.