DAVIS, CALIFORNIA—Chili peppers were first domesticated in central-east Mexico, according to plant scientist Paul Gepts of the University of California, Davis, who led a study of genetic, archaeological, linguistic, and archaeological evidence. Traces of the easily-transported chili pepper, or Capiscum annum, has been found in Romero Cave in eastern Mexico, and from Coxcatlán Cave, located further south. These two samples are between 7,000 and 9,000 years old. “By tracing back the ancestry of any domesticated plant, we can better understand the genetic evolution of that species and the origin of agriculture—a major step in human evolution in different regions of the world,” Gepts told Live Science.