![Figure 2](/ServeContent?url=http%3A%2F%2Fhgp.sagepub.com%2Fcontent%2F2%2F1%2F876940%2FF2.medium.gif)
Organization of selected human GST gene clusters. “P” indicates a pseudogene (e.g., AP3). The GST classes shown are Alpha (chromosome 6p12) [68, 69], Mu (chromosome 1p13) [45, 46], Theta (chromosome 22q11.2) [70, 71], and Omega (chromosome 10q24.3) [72, 73]. (A reverse transcribed pseudogene of the Omega class, found on chromosome 3 [72], is not shown.) GST genes are shown as white text on black background and pseudogenes are shown as black text on a grey background. The direction of each gene is indicated by the arrow. The genes GSTM1, GSTT2B, and GSTT1, each of which is commonly deleted, are shaded white. Genes DDT and DDT-L, in the Theta cluster, encode the enzyme D-dopachrome tautomerase. DDT-L is commonly deleted along with GSTT2B. The figure is not drawn to scale.