Fig. 2.

Number of genes identified as differentially expressed in TCDD-treated mice relative to the time-matched vehicle controls. Same filtering criteria (|fold change| > 1.5, P1(t) > 0.9999) were used to obtain the number of differentially expressed genes in the short-term (light gray bars, 2–168h; Boverhof et al., 2005) and long-term TCDD study (dark gray bars, 1–72 weeks). TCDD-elicited differential gene expression was maximal after 1 week of exposure and then decreased to zero at 24 weeks, followed by negligible gene expression changes at 36 and 72 weeks, respectively.