Anna was responsible for the gestation of naturally occurring foodstuffs during her tenure in the Rivet City science lab, where she worked under Doctor Li. Soon kidnapped by the Enclave, Anna Holt was "forced" to help the Enclave in their experiments at Raven Rock. She was astonished by the technology the Enclave possessed and she quickly told them everything about Project Purity. She can be found at Rivet City science lab before The Waters of Life, and at Raven Rock after The Waters of Life, located in a room near the science lab.
The American Dream: She can be found inside Raven Rock, now working for the Enclave. Killing her at this point will still grant negative Karma, but leaving her to be blown up along with Raven Rock will not.
Upon first walking into the science lab at Rivet City, one can see Anna having an argument with Dr. Zimmer about his missing android and telling him that Doctor Li has more important things to do. This can serve as a tip to the existence of the Replicated Man quest.