Before revision:  Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1) using genomic sequences collected for almost a decade from  treated and untreated patients, to understand how proteins adapt to a changing environment of treatment over time.
After revision:  Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1) using protease sequences collected for almost a decade from treated and untreated patients, to understand how proteins adapt to a changing environment of treatment over time.