After completing her studies in Leningrad, Berg moved to Moscow to work at the A. N. Severtsov Institute of Evolutionary Morphology under .I .I Schmalhausen. The Institute was evacuated to Kazakhstan in 1941, but the following year Berg re- turned to Moscow to work on her doctoral dissertation. From 1944-1947 she worked as a senior researcher at the Severtsov Institute and part-time at the Zoological Institute of Moscow University. Lysenkoism pres- sured Soviet geneticists, pushing many researchers out of their institutions. By the time of Berg's dismissal from Moscow University, "there was only one geneticist at Moscow University's Department of Darwinism and one geneticist at the Institute of Evolutionary Morphology, and I was both ofthem". Berg continued botanical experiments to support her doctoral dissertation and published work relating to her father's expeditions. In 1948, Berg began work as an associate professor of the Herzen Leningrad Pedagogical Institute, and in 1949 moved to the All-Union Research Institute of Lake and River Fish Management. She then worked at Leningrad State University; between 1954-1963 she was an assistant, then associate professor, and finally senior research associate. From 1964-1968, Berg head- ed the Laboratory of Population Genetics of the Institute of Cytology and Genetics and worked as a lecturer at Novosibirsk State University.