Creative DNA Computing: Splicing Systems for Music Composition

Splicing systems are a form of DNA computing as they mimic the recombination process among DNA molecules. This work discusses the use of splicing systems to build automatic tools for reproducing human beings' creativity, in the context of automatic music composition. More specifically, this work describes three general splicing system approaches for automatic music composition, and their application to two specific cases, namely composing 4-voice music and composing Jazz solos in a given style. Examples of music composed by the systems are presented.

Descriptional Complexity of Semi-Simple Splicing Systems

Splicing systems are generative mechanisms introduced by Tom Head in 1987 to model the biological process of DNA recombination. The computational engine of a splicing system is the “splicing operation”, a cut-and-paste binary string operation defined by a set of “splicing rules”, quadruples [Formula: see text] where [Formula: see text] are words over an alphabet [Formula: see text]. For two strings [Formula: see text] and [Formula: see text], applying the splicing rule [Formula: see text] produces the string [Formula: see text]. In this paper we focus on a particular type of splicing systems, called [Formula: see text] semi-simple splicing systems, [Formula: see text] and [Formula: see text], wherein all splicing rules [Formula: see text] have the property that the two strings in positions [Formula: see text] and [Formula: see text] in [Formula: see text] are singleton letters, while the other two strings are empty. The language generated by such a system consists of the set of words that are obtained starting from an initial set called “axiom set”, by iteratively applying the splicing rules to strings in the axiom set as well as to intermediately produced strings. We consider semi-simple splicing systems where the axiom set is a regular language, and investigate the descriptional complexity of such systems in terms of the size of the minimal deterministic finite automata that recognize the languages they generate.

Generalisations of Splicing Languages in DNA Splicing Systems Involving Two Palindromic Restriction Enzymes

DNA splicing system is initiated by Head to mathematically model a relation between formal language theory and DNA molecules. In DNA splicing systems, DNA molecules are cut and recombined in specific ways with the existence of enzymes, which are also known as endonucleases, to produce further molecules. The resulting molecules are depicted as splicing languages by using concepts in formal languages theory. A sequence of restriction enzyme that reads the same forward and backward is called as a palindromic rule. Previously, researches on different types of splicing languages have been done. In this research, generalisations of splicing languages resulting from DNA splicing systems with non-overlapping cutting sites of two palindromic restriction enzymes are presented as theorems using the induction method. The results from this research are beneficial for researchers in the field of DNA computing since it contributes to the development of splicing languages generated from DNA splicing systems with different palindromic restriction enzymes by using these generalisations.

Automata for DNA Splicing Languages with Palindromic and Non-Palindromic Restriction Enzymes using Grammars

In DNA splicing system, DNA molecules are cut and recombined with the presence of restriction enzymes and a ligase. The splicing system is analyzed via formal language theory where the molecules resulting from the splicing system generate a language which is called a splicing language. In nature, DNA molecules can be read in two ways; forward and backward. A sequence of string that reads the same forward and backward is known as a palindrome. Palindromic and non-palindromic sequences can also be recognized in restriction enzymes. Research on splicing languages from DNA splicing systems with palindromic and non-palindromic restriction enzymes have been done previously. This research is motivated by the problem of DNA assembly to read millions of long DNA sequences where the concepts of automata and grammars are applied in DNA splicing systems to simplify the assembly in short-read sequences. The splicing languages generated from DNA splicing systems with palindromic and nonpalindromic restriction enzymes are deduced from the grammars which are visualised as automata diagrams, and presented by transition graphs where transition labels represent the language of DNA molecules resulting from the respective DNA splicing systems.

Computation of Splicing Languages from DNA Splicing System Based on Sequences of Restriction Enzymes

In DNA splicing systems, restriction enzymes and ligases cleave and recombine DNA molecules based on the cleavage pattern of the restriction enzymes. The set of molecules resulting from the splicing system depicts a splicing language. In this research, an algorithm for DNA splicing systems is developed using C++ visual programming. The splicing languages which have been characterised through some theorems based on the crossings and sequences of the restriction enzymes, are generated as the output from this computation. In order to generate the splicing languages, the algorithm detects and calculates the number of cutting sites of the restriction enzymes found in the initial molecules, determines whether the sequence of restriction enzyme is a palindrome or not, and if the restriction enzymes have the same or different crossings. The results from this research depict the splicing languages obtained from the manual computations, which contributes to the development of computational software in DNA computing.

DNA Splicing Systems with at Most Two Cutting Sites of a Non-Palindromic Restriction Enzyme

The modelling of splicing systems is simulated by the process of cleaving and recombining DNA molecules with the presence of a ligase and restriction enzymes which are biologically called as endodeoxyribonucleases. The molecules resulting from DNA splicing systems are known as splicing languages. Palindrome is a sequence of strings that reads the same forward and backward. Research on generalisations of splicing languages in DNA splicing system involving palindromic sequences for restriction enzymes has been done previously. In this research, the splicing languages resulting from DNA splicing systems with one non-palindromic restriction enzyme are determined using the notation from Head splicing system. The generalisations of splicing languages for DNA splicing systems involving one and two non-overlapping cutting sites of one non-palindromic restriction enzyme are presented in the first and second theorems, respectively, which are proved using direct and induction methods. The result from the first theorem shows a trivial string which is the initial DNA molecule; while the second theorem determines a splicing language consisting of a set of resulting DNA molecules from the respective DNA splicing system.