B. dendrobatidis resequencing project

Batrachochytrium dendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. However, the geographical origin of this infection, its patterns of global spread and principle mode of evolution remains largely unknown. Using next-generation sequencing data, we show that the majority of isolates, and all those that are associated with amphibian epizootics, comprise a single >99.9% genetically identical lineage with a pan-global distribution. Uniquely, this 'Global Panzootic Lineage' (BdGPL) of Bd manifests extensive inter-genomic phylogenetic conflict and blocks showing loss-of-heterozygosity, showing that recombination is unique to this clade. We discover two other highly divergent lineages of Bd with different morphological and phenotypic characters, and show that hypervirulence is unique to the BdGPL. We hypothesise that ancestral recombination between previously allopatric lineages followed by anthropogenically-mediated global spread of the progeny has led to contemporary disease-driven losses in amphibian biodiversity.