Repetitive Elements in Myriapoda: Genomic Diversity and Evolution

Abstract Background Transposable elements (TEs) are major drivers of genome evolution, yet their diversity and dynamics remain poorly characterized in many non-model animal lineages, including Myriapoda. The recent expansion of genomic resources in this group now enables comparative analyses, but TE annotation remains challenging due to heterogeneous assembly qualities and the complexity of repeat landscapes. Results We present a standardized comparative analysis of repetitive elements across 36 myriapod species, providing a comprehensive overview of TE abundance, composition, and activity. TE landscapes vary strongly among lineages, with TIR elements dominating most genomes, while LTR elements show lineage-specific expansions, particularly in several chilopods. Genome size correlates strongly with TE abundance in diplopods, whereas this relationship is weaker and more variable in chilopods, suggesting contrasting evolutionary dynamics across clades. Repeat divergence analyses further reveal signatures of recent TE activity, indicating that repeat-driven genome remodeling remains ongoing in myriapods. Conclusion Our results demonstrate that genome size evolution in Myriapoda reflects lineage-specific TE dynamics and highlight the importance of standardized annotation for cross-species comparisons. We additionally provide an automated workflow for repeat annotation and visualization, enabling reproducible large-scale analyses of repeatomes in non-model organisms, and make this workflow publicly available at: https://github.com/dorinemerlat/exogap.