Wild Almonds Were Deadly Poisonous Before a Genetic Mutation

The almonds in your snack mix were once deadly killers. Wild, bitter almonds contain amygdalin, a compound that breaks down into cyanide when ingested. Consuming just 50 bitter almonds could potentially kill an adult, and a handful is lethal to a child. But thousands of years ago, a spontaneous mutation occurred in a wild almond tree that inhibited amygdalin production. This single genetic change 'turned off' the poison-making ability, creating the sweet almonds we know today. Archaeological evidence shows humans cultivated almonds as early as 3,000 B.C., though geneticists believe we may have started even earlier, around 12,000 years ago. Once humans discovered these sweet variants, we embraced them enthusiastically. Farmers selected trees producing sweet seeds, and over generations, domesticated almonds lost almost all their amygdalin. The 'sweet' allele is dominant, so selective breeding quickly spread the trait. Today, most people have never heard of poisonous almonds, though they still exist in the wild.