If A has a given function, and B has a given function, but they both have
the same DNA, then my hypothesis is that they could not have evolved. The
common text-book idea of the origin of multicellularity is that various
cells developed inter-dependence. Then, they somehow got together. But
if A & B have the same DNA but a different environment, making a different
expression of the DNA, then their whole scenario brakes down, I believe.
Could someone tell me if indeed A & B have the same DNA in some of the
simple multi-cellular creatures?