Multivariate breeder's equation ($\Delta \overline{\mathbf{z}}=\mathbf{G}\mathbf{\beta }$)

The local response approximation $\Delta \overline{\mathbf{z}}=\mathbf{G}\mathbf{\beta }$, where $\mathbf{G}$ is the additive genetic covariance matrix and $\mathbf{\beta }$ is a phenotypic selection gradient. Correlated inheritance can facilitate one direction of response and inhibit another.^[ref]