Starships: a new frontier for fungal biology.

Starships are a newly discovered superfamily of gigantic transposable elements (TEs) found across hundreds of species of Pezizomycotina fungi. Analysis of Starships provides unprecedented opportunities to reveal rules of life governing mobile element-host interactions across eukaryotes and prokaryotes. Starships have increased capacity to interact with fungi as bona fide genetic mutualists and parasites compared with other fungal TEs, because they carry dozens of genes as cargo. Starships horizontally transfer between fungal species, and their cargo often encodes conditionally beneficial phenotypes. We propose an updated model of fungal genome evolution that features the ' Starship compartment,' a distinct genomic space consisting of all Starship elements within a species. Transposable elements (TEs) are semiautonomous genetic entities that proliferate in genomes. We recently discovered the Starships , a previously hidden superfamily of giant TEs found in a diverse subphylum of filamentous fungi, the Pezizomycotina. Starships are unlike other eukaryotic TEs because they have evolved mechanisms for both mobilizing entire genes, including those encoding conditionally beneficial phenotypes, and for horizontally transferring between individuals. We argue that Starships have unrivaled capacity to engage their fungal hosts as genetic parasites and mutualists, revealing unexplored terrain for investigating the ecoevolutionary dynamics of TE-eukaryote interactions. We build on existing models of fungal genome evolution by conceptualizing Starships as a distinct genomic compartment whose dynamics profoundly shape fungal biology. [ABSTRACT FROM AUTHOR]