STUDY OF GENOME SEQUENCES USING GRAPH THEORY

Abstract

This paper proposes a novel study of genome sequences using graph theoretic tools. A genome sequence
is a characteristic sequence of four ‘Nucleotides’ such as ‘Adenine’, ‘Thymine’, Guanine, ‘Cytosine’. These four
macromolecules are represented by their first letters such as A, T, G and C respectively. Genome is entire set
of DNA instructions found in a cell. Human genome consists of 23 pairs of chromosomes located in the cell’s
nucleus, as well as a small chromosome in the cell’s mitochondria. Genome contains all relevant
information needed for an individual to grow and function. Human genome contains about 3 billion
nucleotides. A sequence of three consecutive nucleotides is called ‘Codon’, to be more specific, a ‘Triplet Codon’. One
can construct 64 triplet codons from four nucleotides. During protein synthesis inside a cell, the protein called
‘Ribosome’ makes use of sequence of triplet codons, chooses amino acids and builds required proteins. These
triplet codons play a vital role in the cell action. In a codon sequence, adjacent codons overlap by one nucleotide
or by two nucleotides. All hereditary properties of an individual are decided by these overlaps. This
paper introduces the structure of overlapping and non-overlapping codons using graph theoretic tools.