“…In general, an alignment-free method based on graphical representations of DNA sequences consists of two step, the first of which embed each DNA sequence into an Euclidean space, and the second is to compute the similarity matrix based on certain distance-based methods such as Euclidean distances or correlation angles to realize differences or similarities among DNA sequences. For papers using graphical representation for DNA similarity analysis, see, for example, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].…”