Dynamics of Expression Variability Contribute to Retention of Small-Scale vs. Whole-Genome Duplicates

Genome analyses reveal that gene duplication in eukaryotes is pervasive, providing a primary source for the emergence of new genes. Nevertheless, the mechanisms influencing the probability of early duplicate retention and the emergence of functional biases,such as the enrichment of tandem duplicates in environmental responses, remain unclear. Here, to elucidate the mechanisms and factors determining gene retention, we study a frequently overlooked molecular feature-within-line expression variation, termed expression variability. We demonstrate that, on average, genes with duplicates exhibit higher expression variability than singletons. Furthermore, small-scale duplications (SSDs) and whole-genome duplications (WGDs) display contrasting functional outcomes and time-dependent profiles in expression variability. These findings suggest a potential overarching mechanism that facilitates gene expression divergence, functional gains of environmental responses, and duplicate retention following SSDs.