# Bone marrow transplants and blood DNA **URL:** \ **Category:** Factual Questions\ **Created:** [December 16, 2005, 6:48pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954 "2005-12-16T18:48:46Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 16, 2005, 6:48pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/1 "2005-12-16T18:48:46Z")
I was watching one of the many forensic police shows (it may have been “CSI: Assboink, Idaho”) and in it there was man who had received a bone marrow transplant, and because blood comes from the bone marrow the DNA of his blood was that of the donor, and did not match his “original” DNA (like, of his sperm). This sounded plausible, is this actually the case with recipients of bone marrow transplants? In general, do those who receive a bone marrow transplant have no original marrow left at all? Or is it sometimes or always the case they have a mixture of both original and new marrow, and perhaps have blood of both DNA sets? ---
**Author:** ![irishgirl](https://avatars.discourse-cdn.com/v4/letter/i/8edcca/32.png) [@irishgirl](https://boards.straightdope.com/u/irishgirl)\ **Post date:** [December 16, 2005, 6:56pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/2 "2005-12-16T18:56:46Z")
I know that bone marrow can definitely cause someone to change their blood type (say from and A to an O), because IIRC bone marrow is matched to HLA groups rather than simply blood type. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 16, 2005, 7:40pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/3 "2005-12-16T19:40:07Z")
Found an article about this from New Scientist [http://www.newscientist.com/article.ns?id=mg18825234.600](http://www.newscientist.com/article.ns?id=mg18825234.600) > [@](#): > > …the inmate had received a bone marrow transplant from his brother. As a result, his blood was populated with cells bearing his brother’s DNA profile. > [@](#): > > Until recently, bone marrow transplants involved destroying the patient’s own bone marrow. In such cases their blood will contain the DNA profile of the donor alone. But some treatments in recent years, such as therapies to treat sickle cell disease, retain some of the patient’s original bone marrow, so their blood can contain a mixed DNA profile. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [December 17, 2005, 6:52am UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/4 "2005-12-17T06:52:57Z")
Our Molecular Sequencing lab has a test specifically designed to test how well bone marrow transplants are “taking” by periodicially testing the genetic profile of the patient’s bone marrow samples. If a patient goes from 90% recipient/10% donor to 50%/50% to 10%/90%, it’s a good sign that the donated bone marrow is growing well. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 17, 2005, 12:26pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/5 "2005-12-17T12:26:36Z")
Very interesting, **Smeghead**! But did you mean “by periodicially testing the genetic profile of the patient’s **blood** ”? ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [December 17, 2005, 6:12pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/6 "2005-12-17T18:12:18Z")
> [@Revtim](#): > > Very interesting, **Smeghead**! But did you mean “by periodicially testing the genetic profile of the patient’s **blood** ”? Nope. They take bone marrow samples. ---
**Author:** ![Excalibre](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@Excalibre](https://boards.straightdope.com/u/Excalibre)\ **Post date:** [December 17, 2005, 8:36pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/7 "2005-12-17T20:36:39Z")
If I understand correctly, some procedures require the marrow to be completely destroyed. If you have leukemia, they kill off the bone marrow because that’s where some of the cancerous cells come from. My guess, then, is that when that’s the case, the DNA would only reflect the donor. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 17, 2005, 9:42pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/8 "2005-12-17T21:42:08Z")
> [@Smeghead](#): > > Nope. They take bone marrow samples. Why not just test the blood? Not as accurate? If not, why not? I would have guessed the blood DNA ratio would match the marrow ratio. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [December 18, 2005, 6:10am UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/9 "2005-12-18T06:10:20Z")
> [@Revtim](#): > > Why not just test the blood? Not as accurate? If not, why not? I would have guessed the blood DNA ratio would match the marrow ratio. That’s assuming both types of marrow are producing blood cells at the same rate, which may or may not be true, especially if the original marrow is cancerous, and thus dividing like mad. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 18, 2005, 12:40pm UTC](https://boards.straightdope.com/t/bone-marrow-transplants-and-blood-dna/335954/10 "2005-12-18T12:40:01Z")
Makes sense, thanks.