Graph theory is study of mathematical structures called graphs which are represented by nodes (or vertices) and edges. As we know,
during evolutionary history, not along with DNA mutation subsequent rearrangements also occurred for individuals. This study
involves the use of graph theory to construct a mathematical descriptor for similarity analysis based on various mutation phenomena.
As a DNA sequence can store considerable amount of computational data, a weighted directed graph will be set up for each DNA
sequence. Each edge is assigned a weight in accordance with the distance to be traveled. This approach takes into account both
ordering as well as the frequency of nucleotides so that more data is involved.