Molecular Mechanisms of Evolutionary Innovation

Where do genes come from? All genomes contain genes whose sequences appear unique to a
given species or lineage to the exclusion of all others. These “orphan” genes cannot be related
to any known gene family; they are considered evolutionarily novel and are thought to mediate
species-specific traits and adaptations. In this seminar, I will present an investigation of the
evolutionary origins of orphan genes in eukaryotes. According to our results, most orphan genes
may have evolved through an enigmatic process called “de novo gene birth”. I will present a
series of integrated computational and experimental analyses in budding yeast that begin to
shed light on the molecular mechanisms of de novo gene birth. Serendipitously, these analyses
reveal the existence of thousands of previously unsuspected translated elements in the yeast
genome that appear to mediate beneficial phenotypes yet are evolutionarily transient. I will
discuss the implications of these findings for our understanding of genome, cell and systems
biology.