How can a someone completely unrelated be the best match fora kidney or bone marrow?

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How can a someone completely unrelated be the best match fora kidney or bone marrow?

In: Biology

4 Answers

Anonymous 0 Comments

Organ donors need to match a few key types to be a strong match: blood type, crossmatching, tissue typing, similar size, etc. There is some variance within each of these, but not an enormous amount. And while siblings and close relatives are more likely to share these types (due to sharing more DNA), it’s not super rare for these cases to match between strangers – it’s just less common than among siblings.

To make a similar example, my brother and I both have brown hair, green eyes, and we’re within an inch or so in height. If you look in our immediate family, you’ll find a few other people who match those traits, and a few who won’t (like our sister, who has red hair). If you start to look outside of our family, you’ll find fewer people that match on those traits, but if you look for a little while, you’ll still eventually find matches; they just aren’t as common as they were within our immediate family. It’s similar with these other genetic matches: uncommon between strangers, but if you are able to check a large group of people, some close matches will turn up, because there are only so many possible traits.

Anonymous 0 Comments

Just as someone does not have to be directly related to you to have the same hair color as you, they don’t have to be directly related to you in order to be compatible for an organ transplant. It’s just a bit less likely, since that compatibility depends on more factors than just one single physical feature.

Anonymous 0 Comments

Being related by blood means you had a similar ‘pool’ of DNA to pull from. But DNA is shuffled around a lot during reproduction. Out of a ‘family pool’ of 1,2,3,4,5,6,7,8,9,10, for example, not everyone will be dealt two 5s.

But, someone from another ‘family pool’ of 5,6,7,8,9,10,11,12,13,14,15 might be.

In sexual reproduction, a lot of chance is involved.

Anonymous 0 Comments

First noone is completely unrelated. We are all descendants of mRNA-eve.

For organs only a few parameters need to match. One is the bloodtype, the others are tissue types and so one.

Lets stay with just the bloodtype. It’s not unlikely to find someone of the same bloodtype who you are not closely related to, and your direct relatives might by chance have a different bloodtype. (For example both your parents have AB, you have A and all your siblings B).

Kind of the same applies to all other markers.

Close relatives have the best chance per person, but there are billions of other humans so the chances someone else matches is propably higher than one of your dozen closest relatives.