How The Scorpion's Venomous Sting Evolved

The sting in a scorpion's tail has been connected to common defensive proteins by scientists. Defensins are proteins common to many plants and animals that fight off viral, bacterial and fungal pests.
Researchers investigated the relationship between these proteins and the neurotoxins present in scorpion venom. Their results showed how just a single genetic mutation could convert such a protein into a deadly toxin.