RPC projection example for 7 gene expression variables (x
, ..., x
) and a response variable (y). (a) Grey arrows represent projected gene expression vectors by the response variable. The remaining fractions (dark arrows) are then used for our RPC analysis. (b) The remaining fraction (dark) arrows are redrawn to be centered at the origin. The response variable y becomes the origin in this space. Negatively-correlated genes (e.g., x7) can be reversely directed in this transformation by multiplying their sign (-1) of correlation.