Fong Wan Heng

An Extension of First Order Limit Language

The study on cutting and pasting of DNA molecules under the framework of Formal Language Theory has led to the mathematical modelling of splicing system. The output of splicing system is the splicing language which can be categorized into three types: adult or inert persistent, transient and limit language. In the biological point of view, limit language is predicted to appear after the reaction of DNA molecules and enzyme with the existence of appropriate ligase reached the equilibrium state. In this research, the second order limit language is investigated. It is defined as the distinct language after splicing occurs among the resulting splicing language of the first order splicing language. Besides that, the characteristics of second order limit language are observed based on the properties of the crossing sites of the rules such as left or right context and palindromic via Y-G approach. The results lead to some examples and theorems which are presented in this paper.

An Extension of DNA Splicing System

The first mathematical model of a splicing system that was analyzed in the framework of Formal Language Theory was developed in 1987 by Head. This model consists of a finite alphabet, a finite set of initial strings over the alphabet, and a finite set of rules that act upon the strings by iterated cutting and pasting, generating new strings. In this paper, a new notation for writing rules in a splicing system and a new extension of splicing systems is introduced in order to make the biological process transparent. These are called Yusof-Goode rules, and they are associated with Yusof-Goode splicing systems. Four different classes of splicing systems are discussed: null-context, uniform, simple and SkH systems. Also, counterexamples are given to illustrate relationships between these splicing system classes.

Hierarchy of certain types of DNA splicing systems

A Head splicing system (H-system)consists of a finite set of strings (words) written over a finite alphabet, along with a finite set of rules that acts on the strings by iterated cutting and pasting to create a splicing language. Any interpretation that is aligned with Tom Heads original idea is one in which the strings represent double-stranded deoxyribonucleic acid (dsDNA) and the rules represent the cutting and pasting action of restriction enzymes and ligase, respectively. A new way of writing the rule sets is adopted so as to make the biological interpretation transparent. This approach is used in a formal language- theoretic analysis of the hierarchy of certain classes of splicing systems, namely simple, semi-simple and semi-null splicing systems. The relations between such systems and their associated languages are given as theorems, corollaries and counterexamples.

Second Order Limit Language in Variants of Splicing System

The cutting and pasting processes that occur in DNA molecules have led to the formulation of splicing system. Since then, there are few models used to model the splicing system. The splicing language, which is the product of splicing system, can be categorized into two, namely the adult and limit language. In this research, limit language is extended to the second order limit language. Few problems are approached which lead to the formation of second order limit language which is then analyzed using various types of splicing system.

SOME CHARACTERIZATIONS IN SPLICING SYSTEMS

The splitting and recombinant of deoxyribonucleic acid or DNA by specified enzymes using concepts in Formal Language Theory was first mathematically modeled by Head in 1987. This splicing system, S can be presented as a set of initial string I over an alphabet A that acts upon 5′ or 3′ overhangs of restriction enzymes and can be simply viewed as S = (A, I, B, C). In this paper, a great interest in presenting some relations on certain types of splicing system namely null‐context, uniform, simple, semi‐simple, semi‐null and Sk based on differentiating their rules are given as proposition, corollaries and counterexamples.

Probabilistic simple sticker systems

A model for DNA computing using the recombination behavior of DNA molecules, known as a sticker system, was introduced by by L. Kari, G. Paun, G. Rozenberg, A. Salomaa, and S. Yu in the paper entitled DNA computing, sticker systems and universality from the journal of Acta Informatica vol. 35, pp. 401-420 in the year 1998. A sticker system uses the Watson-Crick complementary feature of DNA molecules: starting from the incomplete double stranded sequences, and iteratively using sticking operations until a complete double stranded sequence is obtained. It is known that sticker systems with finite sets of axioms and sticker rules generate only regular languages. Hence, different types of restrictions have been considered to increase the computational power of sticker systems. Recently, a variant of restricted sticker systems, called probabilistic sticker systems, has been introduced [4]. In this variant, the probabilities are initially associated with the axioms, and the probability of a generated string is ...

Molecular aspects of DNA splicing system

The pioneer model of deoxyribonucleic acid (DNA) splicing system in a framework of Formal Language Theory was introduced by Head that led to the existence of other models of splicing system, namely Paun, Pixton and Yusof-Goode. These entire models are inspired by the molecular biological process of DNA splicing. Hence, this paper focuses on the translucent DNA splicing process, particularly on the generated language. Starting with some preliminaries in a limit graph, this paper also provides the experimental design with the predicted and actual result.

The generative power of weighted one-sided and regular sticker systems

Sticker systems were introduced in 1998 as one of the DNA computing models by using the recombination behavior of DNA molecules. The Watson-Crick complementary principle of DNA molecules is abstractly used in the sticker systems to perform the computation of sticker systems. In this paper, the generative power of weighted one-sided sticker systems and weighted regular sticker systems are investigated. Moreover, the relationship of the families of languages generated by these two variants of sticker systems to the Chomsky hierarchy is also presented.

Automata for subgroups

Recently, the relation of automata and groups has been studied. It was shown that properties of groups can be studied using state diagrams of modified automata and modified Watson-Crick automata. In this work, we investigate the relation of subgroups with the modified finite and Watson-Crick automata. We also establish the conditions for the recognition of subgroups by using the modified automata.

Probabilistic simple splicing systems

A splicing system, one of the early theoretical models for DNA computing was introduced by Head in 1987. Splicing systems are based on the splicing operation which, informally, cuts two strings of DNA molecules at the specific recognition sites and attaches the prefix of the first string to the suffix of the second string, and the prefix of the second string to the suffix of the first string, thus yielding the new strings. For a specific type of splicing systems, namely the simple splicing systems, the recognition sites are the same for both strings of DNA molecules. It is known that splicing systems with finite sets of axioms and splicing rules only generate regular languages. Hence, different types of restrictions have been considered for splicing systems in order to increase their computational power. Recently, probabilistic splicing systems have been introduced where the probabilities are initially associated with the axioms, and the probabilities of the generated strings are computed from the probabilities of the initial strings. In this paper, some properties of probabilistic simple splicing systems are investigated. We prove that probabilistic simple splicing systems can also increase the computational power of the splicing languages generated.