This may sound like a dumb question but I’m curious. My mom gets transfusions about twice a year. I’ve always wondered if having different DNA put into your body has any affect on your existing DNA. What if you get a full transfusion and you have more new blood in you than old? What happens then?
A hematologist will be along shortly to explain how long transfused blood stays in the body before being broken down and excreted.
I’ll just say that there is more DNA in your mom’s body that just her blood. Every cell of every tissue retains its original DNA. Yes, blood circulates to every organ, but it transfers only dissolved gases & nutrients, not DNA.
Packed red blood cells don’t even contain any DNA.
It seems we did this topic just a few months ago, but damned if I can’t find the thread right now.
Ah, here it is.
Hey thanks, but I’m still confused. How do they remove the leukocytes from the blood before it is put into the other person?
I’m not a doctor, but i’ve seen one on TV. I’m guessing they centrifuge it to separate out all the different components.
Well, I don’t quite understand how they seperate the cells in blood but like TheeGrumpy said above, there is DNA in every tissue and organ and such in the body. Well, assuming the new blood circulates along with the old blood down the same veins and such, wouldn’t it get to all the tissues? If it did get to the tissues, could it start to tell the tissue what to do, being DNA?
No. Most emphatically no. Even if you put in white blood cells (which have DNA), the DNA stays in the white blood cells. Your blood cells don’t go around telling your liver cells how to do their job. Your liver cells have their own DNA, and don’t need any help.
Blood cells in your vessels are dead ends. They don’t reproduce. There are blood stem cells in your bone marrow that make new blood cells, which then go out in your blood vessels and die after a few days at most. They’re then broken down and the parts are either reused or excreted.
oh, there are different kinds of DNA? Hm, well in that case that makes sense. So here’s what I’m getting so far: when my Mom goes in to get a transfusion they seperate the cells in the blood and she ends up getting little to none of the donor’s actual DNA. If she were to get any DNA it would most likely not be alive (since Smeghead said DNA doesn’t live more than a few days in your stream) and even if it was, it couldn’t tell her lung cells what to do since they have thier own DNA for that purpose…
Am I right?
I’m too tired to nitpick, but basically, yes, you’ve got it right.
as long as I have the general idea. Thanks.
Yeah, don’t try and give that explanation on your next biology test, but you’ve got the right conclusion, which is what’s important, I guess.
So if you committed a crime and you were caught as a suspect shortly after a blood transfusion and had to give a blood sample for DNA examination to the police - would the sample not be your DNA yet and could you conceivably get off being linked to the crime?
Crikey - why do I want to know this?
Sorta.
DNA doesn’t live-- it’s just a chain of amino acids. The cells that it is in only last for a certain amount of time.
But you’re good on the other part that other cells read off of their own copy of the DNA.
GAAAH!! No, it isn’t! It’s a chain of nucleic acids! AMINO acids make up proteins, which are completely different.
Pant, pant.
Sorry. There have just been too many of these types of threads lately.
But on Law & Order all you need to do is get a swab of the inside of the suspected’s cheek in order to get DNA. Then they can match it to the DNA in the little pieces of skin found under the victim’s fingernails. See? No blood involved!
IANAForensicScientist but I always see them on TV.
Whew. No one noticed before I got a chance to fix this. I meant nucleotides, not nucleic acids. Nucleotides. That’s an example of somebody-or-other’s law, I’m sure.
I quit for today.
There aren’t really different types of DNA, exactly. It’s more like the DNA is a script for a play. The whole cast has a full copy of the exact same script, but they read different bits of it. The cells in different tissues only actually read and use certain bits of the DNA that pertain specifically to them, just like actors only read the stage directions for scenes they’re actually in.
It may also help to think of it as a big company with the DNA as the Standard Operating Procedure. Every employee (cell) is given a complete copy of the SOP at hiring, even the parts that are about other departments. Nobody bothers to read the parts about other departments, because it doesn’t affect their jobs, but it’s there anyway.
Shipping and Receiving (the blood) interacts with all the production departments, but they don’t get to call any of the shots within those departments. Their job is to schlep stuff around and shut up about it, not to decide how to make stuff. If your whole S&R department is out sick or something, you bring in an outside contractor to haul things around (a transfusion). This new company has its own SOP, but that doesn’t matter. Their job is to schlep stuff around and shut up about it, especially since they’re just temps.
Besides, as has been pointed out before, the DNA isn’t alive in the first place. The cells that carry the DNA are alive, but they only live a few days.
Just to counter again a point that has come up several times, there * is no dna in red blood cells*. A red blood cell doesn’t have a nucleus, therefore doesn’t have any dna.
There’s no DNA in mammalian red blood cells, no. There is, however, DNA in avian RBC’s, and I think in reptilian RBC’s.
Besides, I was trying to clarify for the OP what happens if some nucleated cells manage to slip in along with the RBC’s during a transfusion.