Graph theory is an efficient bioinformatics approach that offers a methodical approach to modelling and evaluating complex biological data. In this work graph theory was utilized for comparing DNA sequences. Each DNA sequence was break up into nucleotide couples, from which weighted loop digraphs with sixteen vertices was constructed. To assess the sequence similarity distance metrics like Cosine, Correlation, and Jaccard were employed. Nucleotides fragments of 1 different species were examined to confirm the methodology. This research elucidate as an effective tool graph theory is applied for sequence comparison and investigation of biological data in the field of bioinformatics.