Expression signals for strongly correlated genes in the lung. Numbers indicate BXD strains, and the parental C57BL/6J and DBA/2J strains as well as F1 individuals are presented. Expression signals of (A) Klra3 and Gzma (p < 10-16) and (B) Klra3 versus Il18rap (p < 10-11) were strongly correlated. (C) List of nine genes highly correlated with the first principal component of the expression of Gzma, Klrg1, Klra3 and Il18rap. (D) Strong correlation between the first principal component and Prf1 (p < 10-16). X- and Y-axis of the plots show the names of genes used for the analysis.