First insights into the satellitomes and new evidence for the absence of canonical insect telomere in the Neuroptera order.

Abstract

Repetitive DNA is a major component of eukaryotic genomes, playing structural and evolutionary roles. However, in Neuroptera, its characterization remains unexplored. To address this, we analyzed the satellitomes of two Chrysopini (Chrysopidae) species using cytogenomic tools, also investigating telomeric and ribosomal DNA (rDNA). The canonical insect telomeric motif was absent, and rDNA clusters showed variation compared to other neuropterans, despite karyotype stasis (2n = 12, XY). Satellite DNA (satDNA) abundance varied between Ceraeochrysa cincta and Chrysopa pallens, representing a minor fraction of their repetitive DNA content. Notably, no satDNA sequences were shared between species, suggesting a rapid turnover. Exceptionally, the second most abundant satDNA in each species showed low sequence similarity and a putative common origin. A relationship between satDNAs and transposable elements (TEs) was also observed. Chromosome mapping revealed that abundant satDNAs accumulated in euchromatin, providing insights into their genomic distribution. These findings enhance our understanding of satDNA organization in Neuroptera, offering a foundation for future genome assembly efforts and evolutionary studies in these insects.