if you just had a blood transfusion and u killed someone, hus DNA would be found?

Question

i just wanted to make the question more intriguing? :)

but anyway, if u just had a blood transfusion, of course your dna is different from the blood to be injected unto u.. (i know, red blood cells dont have dna, imagine platelet..) what is the process it takes for the DNA A (donor) to become DNA B (yours)? how long would it take for the DNA A to acquire your DNA?

* this is a seriously scientific question.. =)

pls explain ur serious answers.. :)

Answer 1

Both - the donor's DNA and the Recipient's DNA would both be present as the donor blood would rapidly mix with the recipient's.

You are right to state that Red Blood Cells have no DNA (because they have no nucleus) but other blood cells such as White Blood Cells and platelets would have the donor's DNA in them which would remain for the life of the donor blood cells. The amount of donor DNA would obviously be relatively low... but...

I recall that a similar question was asked a few months back in the (UK) newspaper The Daily Mail. I can't remember the full details but one person replied that such a case had indeed happened. The donor gave blood and then committed a crime and left his DNA at the crime scene. The recipient was picked up for some other offence and had his DNA screened and was found to be a match to the donor's DNA. It was only a cast-iron alibi that got the recipient off the hook!

Answer 2

Better try to find another alibi...
It depends on how much blood the recipient will receive.
For sure they will detect his DNA but for the donor DNA detection would require to have transfused a quantity above a certain level-don't know what that would be exactly-since it gets "diluted" with the rest of the recipient's blood.

DNA A never becomes DNA B. Simply the cells remain in your organism until they die and thus cells with DNA A gradually disappear from your system. Whatever element added during transfusion that is not recognised as "self" by your organism is removed by the immune system.
It's similar to transplants, though transplants are a more complicated case.

Answer 3

One blood donor donates about one pint or 500 mls of blood. The chances of your being injured at a crime scene and bleeding only that pint of blood are astronomical. Added to that, your blood transfusion was probably made up from blood from various donors. If the loss of one pint of someone's blood was so dangerous that transfusions were needed, they wouldn't take that pint from another person.

That being said, the dna in the blood probably doesn't change at all. The blood from the transfusion is probably a small percentage of your total blood. Every day, blood cells die and your body grows new blood. This is what makes blood donation possible. The new blood cells will die and be replaced by your own fresh blood with your own dna.

Answer 4

A DNA test would find both kinds of DNA in your bloodstream-- yours, and the donor's. In order to have only the other kind of blood in your bloodstream, you would have to have taken ALL the blood from the other person and given yourself a complete transfusion.

(Is that HOW you killed the other person...? If you use this idea in a novel I want credit for it! If you use it for real, you're on your own.)

You can donate a pint of blood every ninety days, so I would suppose that is about how long it takes you to regenerate blood cells. The eventually die and have to be replaced. After enough time, no trace of the foreign DNA will remain in your system.

Good luck delaying the prison system from ordering additional blood tests on you until after you have eliminated the donor DNA from your body!