(1) The quantity of electric charge that may be stored upon a body per unit electric potential; expressed in farads, abfarads, or statfarads. (2) In genetics, a state in the evolutionary context referring to an ability to contain or hold. For example, heat shock protein 90 (Hsp90) acts as a buffer, preventing expression of certain genetic traits by allowing these genetic variations to accumulate and stay silenced under neutral conditions. When the capacitance of Hsp90 is compromised, these cryptic variants are then expressed.