Pooja Singh, Ehsan Pashay Ahi

Although alternative splicing is a ubiquitous gene regulatory mechanism in plants and animals, its contribution to evolutionary transitions is understudied. Splicing enables different mRNA isoforms to be generated from the same gene, expanding transcriptomic and proteomic diversity. While the role of gene expression in adaptive evolution is widely accepted, biologists still debate the functional impact of alternative isoforms on phenotype. In light of recent empirical research linking splice variation to ecological adaptations, we propose that alternative splicing is an important substrate for adaptive evolution and speciation, particularly at short timescales. We synthesise what is known about the role of splicing in adaptive evolution. We discuss the contribution of standing splice variation to phenotypic plasticity and how hybridisation can produce novel splice forms. Going forwards, we propose that splicing be included as a standard analysis alongside gene expression analysis so we can better understand of how splicing contributes to adaptive divergence at the micro- and macroevolutionary levels.