Noise Immunity of Genetic Codes to Point Mutations
- PDF / 113,492 Bytes
- 7 Pages / 594 x 792 pts Page_size
- 47 Downloads / 193 Views
SYSTEMS ANALYSIS NOISE IMMUNITY OF GENETIC CODES TO POINT MUTATIONS I. V. Sergienko,a† A. M. Gupal,a‡ and A. V. Ostrovskiia
UDC 519.217.2
Abstract. The noise immunity of genetic codes with nucleotide mutations is analyzed. The universal code is compared with randomly generated codes. The noise immunity of genetic code against polarity, hydrophobicity, and helix propensity is analyzed. A genetic algorithm for the optimization of noise immunity of a code is described. Keywords: genetic code, mutations, amino acid, nucleotide, codon, genetic algorithm INTRODUCTION A universal genetic code, according to which proteins are synthesized in live organisms based on the information contained in DNA was discovered in the 1960s [1]. Since then the problem of its origin and evolution is a subject of numerous interbranch discussions. According to [2, 3], one of the main factors that could influence the code evolution is increasing its immunity to mutations, i.e., to distortions of genetic information, which inevitably arise in cells of any organism. Within the framework of this approach, it is expedient to analyze genetic using the mathematical apparatus such as information theory. Such studies are described in monographs and papers in biochemistry [4, 5]; however, they are rather depthless. In [6], the stability of genetic code was analyzed with respect to amino acid polarity. In the present paper, we will make an attempt to generalize and systematize the results obtained to date. We will describe the mechanism of mutations and introduce a mathematical apparatus to evaluate the noise immunity of genetic code. We will compare the universal code with radomly generated ones on which certain constraints are imposed. We will analyze the noise immunity of genetic code with respect to the characteristics of amino acids such as polarity, hydrophobicity, and helix propensity. We will describe a genetic algorithm to optimize the noise immunity of the code, present its results, and analyze them from the point of view of different groups of mutations. 1. THE CONCEPT OF NOISE IMMUNITY The information about proteins synthesized by any live organism is known to be encoded by genes, which are DNA sections being sequences of four possible nucleotides (bases): adenine (a), cytosine (c), guanine (g), and thymine (t). Protein is also a sequence of more simple components, 20 amino acids: alanine, cysteine, aspartic acid, glutamic acid, phenylalanine, glycine, histidine, isoleucine, lysine, leucine, methionine, asparagine, proline, glutamine, arginine, serine, threonine, valine, tryptophane, and tyrosine. The universal (standard) genetic code associates each triple of successive nucleotides (codon) of a gene with one of the above-mentioned amino acids (Table 1). Three codons, taa, tag, and tga, so-called stop codons, are associated with no amino acids, they are indicative of the termination of the protein synthesis process. Since the remaining 61 codons encode 20 amino acids, the universal code is characterized by degeneracy: more than one codon c
Data Loading...
