Boolean relationships. Six different types of Boolean relationships between pairs of genes taken from the Affymetrix U133 Plus 2.0 human dataset. Each point in the scatter plot corresponds to a microarray experiment, where the two axes correspond to the expression levels of two genes. There are 4,787 points in each scatter plot. (a) PTPRC low ⇒ CD19 low. (b) XIST high ⇒ RPS4Y1 low. (c) Equivalent relationship between CCNB2 and BUB1B. (d) FAM60A low ⇒ NUAK1 high. (e) COL3A1 high ⇒ SPARC high. (f) Opposite relationship between EED and XTP7.