Weak suppression of visual context in chronic schizophrenia

duplications suggest a mechanism for the colinearity of Hoxd genes in limbs. Current Biology Vol 15 No 20 R822 Figure 2. Maintenance of ParaHox clusters. Schematic of the amphioxus ParaHox cluster (top), with flanking genes, and the mam-malian ParaHox clusters with the mammalian ParaHox paralogy regions. The amphioxus cluster has retained the organisation present in the chordate ancestor. Arrows denote transcriptional orientation, which has been conserved between the ParaHox clusters and the paralogy regions. The pattern of gene linkage and orientation indicates that the mam-malian genomic regions arose from duplications of the entire region, followed by extensive gene loss (indicated by 'X'). Only a single intact ParaHox cluster remains in mammals, and genomic rearrangements have occurred up to its edges, but not within it. Each column of receptor tyrosine kinase genes (yellow) is a distinct paralogy group (i.e. PDGFRA is a paralogue of PDGFRB). FLT4 has been transposed to a different location on the chromosome, and the orientation of FLT3 is the reverse of that of its par-alogues KIT and CSF1R, the orientation of KIT and CSF1R presumably being the same as the ancestral organisation. AmphiSCP1 is reduced to indicate the possibility that it is a retrotransposition (see Supplemental Data). Mammalian PAN3 is reduced because it is not a receptor tyrosine kinase gene and hence is not analysed here.