The classification of the organisms is mainly based on the comparison of their traits, physiological, morphological, and anatomical features. However, all characteristics of living organisms are determined by their genes and proteins. In other words, nucleotide sequences of genes, as well as corresponding amino acid sequences of proteins determine particular traits. As a result, any two related organisms possessing similar morphological features have similar genes. Therefore, knowledge of molecular biology, as well as appropriate skills, can help to analyze the relations between organisms at the molecular level (genes and proteins) that is a powerful tool for the accurate classification of the organisms.