Language - Theoretic Aspects ofDNA

The optimism about the possibilities of DNA computing is based on two central issues: the Watson-Crick complementarity and the massive parallelism of DNA strands. While the latter issue renders exhaustive searches possible and thus may settle problems previously considered intractable, the former issue is the cause behind the universality of many models of DNA computing. Moreover, complementarity can be viewed as a purely language-theoretic operation: undesirable circumstances in a string trigger a transition to the complementary string. This aspect of complementarity is investigated in the present paper, mainly from the point of view of L systems. New types of word sequences will be discovered. Sometimes the resulting decision problems are equivalent to well-known open problems from other areas. TUCS Research Group Mathematical Structures of Computer Science