What happens to DNA after a blood transfusion?

Factual Questions
1

What happens to the DNS contained in the cells of donated blood after it’s inserted into the receiver? My three hypotheses (in the form of a question ;)):

  1. Does the person’s blood “consume” the new blood, essentially destroying the DNA?

  2. Do the cells float around the blood stream independantly, so if you took two samples from different locations, they would theoretically have different DNA?

  3. Do the cells merge and form new DNA?

2

This was sort of covered in this thread.

The long and the short of it is that the blood that you recieve in a donation is basically a temporary supply. The cells contained in it eventually die of old age and are replaced by cells produced naturally by your body. Your DNA is pretty much established throughout your body before birth and the only way to alter that would be by a virus which would infect every cell you own.

3

Mammalian red blood cells don’t contain a nucleus, thus don’t contain DNA. See the thread linked by Mirage for a fuller explanation.

To specifically answer the three questions in the OP:

  1. Yes to the first part of the sentence, see above for the second.
  2. See above.
  3. See above.
4

In addition to the thread linked to above, you should also read the Staff Report Does a blood donation mess up DNA evidence?

5

As I recall in biology class, RBC want to be as efficent as possible in delivering O2 to our somatic cells. So they don’t have a nucleus to make room for more hemoglobin. But without a nucleus, RBC can only survive for 100 and some odd days. I guess some DNA could be “floating” around in the cell(forget what that kind of DNA is called…ggrrr, what is it?).

6

Well, the non-nuclear DNA in people (and all other non-bacteria) is found in the mitochondria, which are the energy powerhouses of the cell. RBCs have some mitochondrial DNA, but I really really doubt that that would affect the recipient in any way.

7

Yes, RBC’s have no nuclear DNA.
But they have mitochondrial DNA. And tansfusions include other types of blood cells that do have nuclear DNA.

But your typical blood cell’s lifetime is measured in hours to days. After that it’s absorbed by the body and its DNA is destroyed. And, unless you’re in really bad shape, the foreign blood is probably going to make up a fairly small percentage of the total.