If you’re at the hospital and you get pumped full of blood, how come it doesn’t change your genetics? Is blood unrelated to that sort of thing and I’m just stupid?
In: Biology
There are three reasons why donated blood doesn’t change your results on a DNA test for your genetics or have long-term impact on your genetics:
* Donations are primarily made up of red blood cells, and **red bloods cells do not contain DNA**. So even though *some* cells have the donor’s DNA, *most* do not and it is hard to detect
* All blood cells are eventually replaced. This takes 90-120 days for red blood cells (including the time the cell existed before the blood was given to you). White blood cells have a much larger range of lifespan (20 days to several years depending on the type
* When blood cells are replaced, they are simply broken down and new ones are made by other parts of **your** body so the last of the donor’s DNA will be gone within a few months
Finally, even though those blood cells have the DNA of the donor, they don’t interact with your other cells or existing DNA to change it in any way.
However, **bone barrow transplant** (see [https://medicalxpress.com/news/2018-01-bone-marrow-transplant-dna.html](https://medicalxpress.com/news/2018-01-bone-marrow-transplant-dna.html)) has a more permanent effect on the DNA in your body, since bone marrow makes white blood cells which contain DNA. This is a pretty permanent change.
Bone marrow transplants can affect a DNA test since that bone marrow will indefinitely produce blood with the donor’s DNA, but will not interact with your *existing* DNA. There have been cases where the donor DNA is found in unexpected places (like hair, see ), but the majority of your body still has your DNA, and the two sets of DNA don’t interact.
It has not been found to impact, for example, the sperm or eggs used in reproduction, so kids wouldn’t have have the donor’s DNA mixed up in them
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