where V is a matrix of expected variance and covariance of the residuals given an evolutionary model and a phylogenetic tree. Therefore, it is the structure of residuals and not the variables themselves that show phylogenetic signal. This has long been a source of confusion in the scientific literature.
In the context where V represents the matrix of expected variance and covariance of residual errors based on an evolutionary model and a phylogenetic tree, it's the residual structure that displays phylogenetic signals rather than the variables themselves. This issue has consistently caused misunderstandings within the scientific community.