Before revision:  While several studies have shown that strong selection pressures enrich epistatic interactions in an evolving protein, little is known about how epistatic interactions themselves change over time when selection pressures are not constant.
After revision:  When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection pressures enrich epistatic interactions in an evolving protein, little is known about how epistatic interactions themselves change over time when selection pressures are not constant.