Cases of convergent evolution — when species independently evolve similar traits in response to shared environmental pressures — can inform the predictability of evolution based on whether similar causative genetic changes occurred. A recent Science paper by Satterlee et al. employed several approaches to identify the genetic changes underlying the repeated, independent gain and loss of prickles across 150 million years of flowering plant evolution.

The possibility of multiple, independent genetic changes to LOG genes across varieties of brinjal eggplant led the authors to test whether LOG gene evolution might underlie the loss of prickles in other closely related eggplant species. Indeed, newly sequenced and assembled genomes of two independently domesticated eggplant species from Africa — both lacking prickles — contained loss-of-function mutations in LOG orthologues. Additional mapping experiments further implicated LOG orthologues in these African species, although the prickled phenotype in one of the species was also associated with an additional, recessive locus. Finally, the team used CRISPR–Cas9 editing to show that loss-of-function changes in the LOG orthologue caused a loss of prickles in one of the African species. Collectively, these experiments demonstrate that independently domesticated eggplant species repeatedly lost prickles probably through changes to a LOG gene.