the obvios :
Na is a metal and reacts to acids and pair swapping..
the chemical is unique ; normal DNA has swapable base pairs
it would not respond well in a nerve cell i believe and in the presence of such compounds as lithium,
a common pharmacutical drug..
it may not self repair as well
it may have to meny complex side affects to truely show all ramifications..
the presence of a metal would imply aquiring more of it from the enviroment..
the sea may not be an entirly sympathetic enviroment for it..
becouse the metal is a big atom it may well be torn from the dna readily... and ionised resulting in an acid etc..
highly responcive to magnetic fields.
*end* (C) RS