Odrade,
how do they do this? isn't it still transgenic tissue? have they been able to render it inert so as not to trigger rejection/shock/immune issue? If it is inert, will it still carry oxygen?
If my limited medical memory recalls correctly, the "typing" of blood is based on the shell of the actual red blood cell. The hemoglobin carried inside does not have this typing issue. There is something on the shell of the cell which determines if someone is A, B, AB, etc. A little searching on the web would probably give a better detailed description than I could give.