Independent genomic trajectories shape adaptation to life on land across animal lineages

How animals repeatedly adapted to life on land is a central question in evolutionary biology. While terrestrialisation occurred independently across animal phyla, it remains unclear whether shared genomic mechanisms underlie these transitions. We combined large-scale comparative genomics, machine learning, and multi-omics data-including proteomics and transcriptomics from stress experiments in 17 species- to investigate the genomic basis of terrestrial adaptation. Gene co-expression networks revealed that stress-response hubs were largely lineage-specific, yet converged in function through the co-option of ancient gene families. Phylogenomic and machine learning analyses supported a dominant role for early-evolving genes, enriched in stress-related functions, with extensive gene loss at terrestrialisation nodes. Our findings support a model of functional convergence via lineage-specific repurposing of conserved genomic elements.