Mechanisms resulting in dosage compensation. (A) Buffering results in non-linear relationship between gene dose and expression due to system properties such as kinetics. This does not result in full compensation but can dampen the effect of gene dose. (B) Feedback requires the generation and detection of an error in expression followed by intervention to correct the error. (C) Feed-forward, as it relates to X chromosome dosage compensation, results in the upregulation of all X chromosome genes regardless of the expression level.