Comparative synthesis of tandem repeats in the control region of Epinephelus mitogenomes (Peciformes: Epinephelidae)

In this study, we analyzed the evolutionary patterns of tandem repeats in the mitochondrial Control Region (CR) of groupers of the genus Epinephelus. This research was based on a comprehensive survey of Epinephelus mitogenomes available in public databases, aiming to recover complete CR sequences. A total of 97 specimens were recovered, including 31 species that contain tandem repeat sequences. The repeated sequences were classified into three categories according to their length: short, medium, and long. The long repeats were restricted to a monophyletic group, while short and medium repeats were more widely distributed across different clades, whereas some species lacked repeats entirely. Given the similarities found among the repeat sequence alignments and the phylogenetic arrangements, it was possible to infer that these segments evolved in synchrony over time, with a process of concerted evolution being the most likely explanation for the evolutionary dynamics of these repetitive DNAs. Correlation analyses further revealed that mitogenome length covaries with CR length and that CR length increases with the full repeat region length, whereas motif length is inversely related to repeat copy number. These patterns underscore how repeat architecture evolves through time in the mitochondrial CR of epinephelid mitogenomes.