Phylogenomic insights into the evolution of subterranean Coleoptera

Subterranean specialization is often accompanied by dramatic phenotypic changes epitomized regressive evolution (e.g. loss or reduction of eyes and pigmentation). Nevertheless, the genetic underpinnings underlying these have been largely unexplored. The beetle tribes Leptodirini (Leiodidae), Hydroporini Bidessini (Dytiscidae) represent ideal systems for exploring genomic basis adaptation to life in subterranean habitats, as both are represented epigean hypogean species including numerous lineages that independently colonized terrestrial freshwater underground habitats respectively (Cooper et al. 2002, Ribera 2010). We investigated gene repertoire evolutionary dynamics surface-dwelling Coleoptera underwent six independent colonization events. generated highly complete transcriptomes eight aquatic fourteen beetles explored their through a phylogenomic approach. Our results indicated was major force facilitating an lifestyle. In contrast, we also observed gain duplication were remarkable drivers adaptation. Gene families experiencing contractions involved carbohydrate metabolism, response starvation, wing disk development, rhodopsin ommochrome biosynthetic processes hypoxia, among many other examples. Conversely, significantly expanded those related regulation apoptosis, alcohol cell redox homeostasis, chitin-based cuticle larval instar oogenesis, negative TORC1 signaling. Moreover found some had experienced more complex dynamic encompassed expansion contraction events, such transcription, nervous system lipid eye DNA repair chemosensation, indicating in-depth reshaping throughout time. At lineage-specific level, did not observe differences between terms loss. Nonetheless, stygobitic showed disparity compared relatives. thus indicate exaptation may facilitated prior diversification tribe, while recent family turnover (dominated loss) guiding surface-to-groundwater transition. These findings shed light towards understanding how toolkit has reshaped fauna from macroevolutionary perspective.