Researchers demonstrated that in rare instances, influenza viruses handicapped by a single mutation can overcome their disadvantage with the aid of other mutations — a phenomenon known as epistasis.

“The term epistasis means that the combined effect of two individual mutations can’t be predicted ahead of time,” said TSRI Postdoctoral Researcher and study first author Nicholas Wu. “Individually, each of these mutations kill the virus, but together, they compensate for each other’s harmful effects.”

Read more at www.sciencedaily.com