Honda et al. (1999) sequenced portions of the mitochondrial 12S and 16S rRNA genes and found the genus Tiliqua to be most closely related to another Australian skink genus, Corucia. Several nucleotide sequences from Tiliqua gigas are available in the NCBI nucleotide database, inclucing MYH, Gadph, Cytb, and partial sequences from the 12S and 16S rRNA genes.