RT Journal Article SR Electronic T1 Meiosis in the human pathogen Aspergillus fumigatus has the highest known number of crossovers JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.01.14.476329 DO 10.1101/2022.01.14.476329 A1 Ben Auxier A1 Frank Becker A1 Reindert Nijland A1 Alfons J. M. Debets A1 Joost van den Heuvel A1 Eveline Snelders YR 2022 UL http://biorxiv.org/content/early/2022/01/15/2022.01.14.476329.abstract AB Evidence from both population genetics and a laboratory sexual cycle indicate that sex is common in the fungus Aspergillus fumigatus. However, the impact of sexual reproduction has remained unclear. Here, we show that meiosis in A. fumigatus involves the highest known recombination rate, producing ~29 crossovers per chromosome. This represents the highest known crossover rate for any Eukaryotic species. We validate this recombination rate by mapping resistance to acriflavine, a common genetic marker. We further show that this recombination rate can produce the commonly encountered TR34/L98H azole-resistant cyp51A haplotype in each sexual event, facilitating its rapid and global spread. Understanding the consequences of this unparalleled crossover rate will not only enrich our genetic understanding of this emergent human pathogen, but of meiosis in general.One-Sentence Summary Genetic exchange between chromosomes during sex in Aspergillus fumigatus is higher than in any other known organism.Competing Interest StatementThe authors have declared no competing interest.