Examples for variations of expression levels in different BXD and inbred mouse strains and ge-nome-wide analysis of cis- and trans -eQTLs. (A) Log2 expression levels for Ang1 and (B) corresponding cis-eQTL signal. The numbers at the top are chromosomes. The blue line represents the significance level of the QTL expressed as LRS score (likelihood ratio statistic). A positive additive coefficient (green line) indicates that DBA/2J alleles increased trait values. A negative additive coefficient (red line) indicates that C57BL/6J alleles increased trait values. The two horizontal lines mark the genome-wide significance levels at p < 0.05 (red line) and p < 0.63 (gray line). Ang1 is located on Chr 14 (triangle) and the QTL peak is at the same location as the gene. (C) Log2 expression levels for Cyp1a1 and (D) corresponding trans eQTL peak. Cyp1a1 is on chromosome 9 (triangle) and the QTL was found on chromosome 12.