compensatory mutation – this refer to an additional mutation, usually in the context of the fitness of a virus. For example, the mutations that stop a drug form working often stop the virus from reproducing as well. Additional mutations that return the virus to it’s former fitness are called compensatory mutations. They compensate for the reduced viral fitness. See revertant mutation.
Glossary
Selected words and phrases
adefovir – anti-viral drug used to treat hepatitis B.
cholesterol – kind of lipid (blood fat).
BMI (body mass index) – a calculation using height and weight that is used to decide whether someone is over or under weight.
minor mutation – a drug resistance mutation that have a big impact on whether a drug continues to work. This used to be called a secondary mutation.