Fungal species boundaries in the genomics era

Genomic data has opened new possibilities to understand how organisms change over time, and could enable the discovery of previously undescribed species. Although taxonomy used to be based on phenotypes, molecular data has frequently revealed that morphological traits are insufficient to describe biodiversity. Genomics holds the promise of revealing even more genetic discontinuities, but the parameters on how to describe species from genomic data remain unclear. Fungi have been a successful case in which the use of molecular markers has uncovered the existence of genetic boundaries where no crosses are possible. In this minireview, we highlight recent advances, propose a set of standards to use genomic sequences to uncover species boundaries, point out potential pitfalls, and present possible future research directions.