The genome organization of repetitive sequences in the Golden Damselfish, Amblyglyphidodon aureus (Cuvier, 1830) (Family Pomacentridae): insights from extensive pericentric inversions

The genus Amblyglyphidodon (damselfishes) is one of the most distinctive fish groups in the Indo-Pacific coral reef ecosystem. It consists of 11 recognized species, which display complex taxonomic relationships and cryptic lineages across their extensive range, often inhabiting coral environments. The timing of evolutionary divergences among these species varies greatly, and the cytogenetic events that accompanied their diversification remain poorly understood. In this regard, chromosomal divergence analysis from a phylogenetic viewpoint provides valuable insights into karyoevolutionary trends. In this study, we employed conventional cytogenetic and cytogenomic techniques to investigate the Golden Damselfish, Amblyglyphidodon aureus, focusing on mapping repetitive DNA elements and transposable elements, including 18S rDNA, 5S rDNA, (CA)15, (GA)15, and (CAA)10. The result show that A. aureus has a distinct karyotype (2n=48, FN=96), characterized by numerous bi-armed chromosomes, with pericentric inversions playing a key role in its karyotypic structure. Pericentric inversions often function as postzygotic reproductive barriers in many species, and this may also be the case for A. aureus. These chromosomal differences illustrate the contrasting evolutionary pathways within the Amblyglyphidodon genus, shedding light on the karyotypic characteristics that define the group.