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by jamesaguilar 5267 days ago
As a total non-biologist, doesn't the "10/10" refer to the parts of the cells that touch and communicate? That is, the interface? If so, I would guess that what DNA is inside doesn't matter for the purpose of compatibility. Walks like a duck . . .
2 comments
mbreese 5267 days ago
The central dogma of molecular biology is:

    1) DNA is transcribed to RNA
    2) RNA is translated into protein
    3) Proteins do work
(This is a gross simplification, but is still a good working model)

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.

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possibilistic 5267 days ago
The 10/10 match refers to HLA typing:

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.

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