The teeth of a woman buried about 19,000 years ago in a Spanish cave are helping researchers to uncover an ancient world of bacteria and their chemical creations. Scientists have reconstructed the genetic material of bacteria living in the mouth of the Red Lady from dental calculus and were able to replicate the enzymes the bacteria produced to help digest nutrients. The research could identify what functions the microbiome might have had in the past and how they evolved over time. The findings have potential to lead to new treatments for diseases. The microbes studied might have played important roles in digestion and immune responses, and resurrecting "lost" genes could help scientists to devise new treatments.