Patterns of genomic variation reveal a single evolutionary origin of the wild allotetraploid Mimulus sookensis.

This article focuses on elucidating the evolutionary origin of the wild allotetraploid monkeyflower species *Mimulus sookensis*, which arose via hybridization between self-compatible diploid species in the *Mimulus guttatus* complex. Using a newly generated chromosome-scale reference genome and whole-genome sequencing data, the study provides clear evidence that *M. sookensis* has a single evolutionary origin, with one subgenome derived from the selfing diploid *Mimulus nasutus* (likely the maternal progenitor) and the other subgenome closely related to, but not nested within, the outcrossing species *Mimulus decorus*. The findings challenge previous reports suggesting multiple origins and highlight the role of self-fertilization in facilitating the establishment of this polyploid species. This work establishes *M. sookensis* as a valuable model for studying the genetic and ecological mechanisms underlying polyploid speciation.