The historical domestication of a Clostridium botulinum strain used for the industrial production of botulinum neurotoxin.

A domesticated Clostridium botulinum strain used for industrial botulinum neurotoxin production accumulated nearly 100 genetic changes, including a hypermutator mutation, over its laboratory history.

• Why it matters: Understanding microbial domestication reveals how human-driven selection shapes bacterial genomes, which is important for both industrial applications and evolutionary biology.
• What they did: Analyzing over 1,000 C. botulinum genomes, the study identified the strain's closest relatives, inferred its most recent common ancestor, and documented genetic changes, including gene loss and mutation rate increases.
• The result: The findings demonstrate how laboratory conditions and industrial selection drive bacterial evolution, providing a genome-based example of microbial domestication and a framework for studying adaptation in microbial systems.