From few to many: How non-model organisms' genomics broadened our understanding of molecular evolution.

For much of the 20th century, our understanding of genetics and evolution was predominantly shaped by intensive studies of a few model organisms such as Drosophila melanogaster, Caenorhabditis elegans, and Mus musculus. While these species provided fundamental insights, their laboratory-adapted characteristics potentially made them evolutionary outliers. The advent of next-generation sequencing technologies and sophisticated bioinformatic tools has increased accessibility of genomic research, enabling comprehensive studies of diverse non-model organisms across the tree of life. This expansion has substantially transformed our understanding of molecular evolution, revealing, for example, that convergent evolution operates through multiple mechanisms across different organizational levels, that speciation is a genomically heterogeneous process involving structural variants and adaptive introgression, and that genome architecture exhibits extensive variation in size, content, and organization. Using aquatic mammals as exemplars, we illustrate how comparative genomics of non-model species illuminates the molecular basis of convergent and divergent adaptations. This paradigm shift demonstrates that understanding evolution's general principles and creative solutions requires embracing life's full diversity.