1) Pregnant women -- During pregnancy, and to some extent afterward, the mother's blood contains cells from the fetus she is carrying. Some of these cells migrate to other places of the body. Scientists hypothesize that this is part of why pregnancy may lower cancer risk -- something about how the mother's immune system deals with these foreign cells. This is called fetal microchimerism. http://www.scientificamerican.com/article.cfm?id=fetal-cells...
2) Chimeric people. In rare cases, a human can be born that is made up of two separate DNA profiles. http://en.wikipedia.org/wiki/Chimera_(genetics)
Completely off-topic: I feel more grateful for the access to Wikipedia after a blackout day.
Good luck, Amit, with your plan!
I'd be interested (obviously) in finding out what other implications this might have for me long term besides enabling me to life a life of crime. ;-)
This might be the one: http://www.csiguide.com/episodedetail.aspx?csi=157.
I'd give you a wikipedia link, but apparently I can't use google cache.
1) DNA is transcribed to RNA
2) RNA is translated into protein
3) Proteins do work
In this case, the 10/10 are probably cell surface markers, which are proteins in a specific conformation (with possibly some other types molecules attached). And yes, one of their roles is touching and communication. So the important part for compatibility is that the DNA that ultimately makes those proteins match Amit's DNA. After that, you have made a pretty good match, so you are then just hoping that they are healthy in all other regards.
To use a programming analogy, the 10 markers could represent an Interface definition. Amit's blood has that Interface, but the underlying class has a severe bug. The donor's blood has the same Interface, but has a better implementation.
http://en.wikipedia.org/wiki/Human_leukocyte_antigen
These are the human MHC molecules that present antigen to T-cells. Unfortunately for the transplant process, a vast number of HLA alleles exist for each locus. This is important evolutionarily for population disease aversion, but makes the process of finding a match very difficult.
Central tolerance makes our immune system unreactive to self antigen. Foreign HLA present in tissue grafts will never be screened out by negative selection since this process requires expression of our own genes to cull any B or T cells that are self-reactive. Anything foreign will most certainly have reactive cell-surface epitopes (to varying degrees of reactivity).
Try reading up on central tolerance, somatic recombination, and clonal selection if you get the chance as it's a beautiful example of nature stumbling upon metaheuristic optimization:
http://en.wikipedia.org/wiki/Central_tolerance
http://en.wikipedia.org/wiki/Clonal_selection
http://en.wikipedia.org/wiki/V(D)J_recombination
To me, these are starker, more potent examples of biological optimization processes than evolution -- they're ongoing in your body right now.
Edit: chimeracoder
Huh. :)
[1] http://www.time.com/time/health/article/0,8599,1858843,00.ht...
Overall, 75% of AML transplant patients survive year one, 50% make it through year five.
That's actually really fascinating. This perpetuates for life? This would seem to imply that a person who's received a transplant will, thirty years later, be walking around with two separate sets of DNA, as the other cells in the body presumably would not change.
Given that DNA is (indirectly) responsible for the way that cells communicate with one another (among other things), I wonder if this dichotomy creates any complications in other ways. (Not counting potential graft-host disease rejection - I'm talking about further down the line).