Representing phenotype annotations using postcomposition and EQE syntax. In the image from Simmons et al., 2012 [53], pes^vu166/vu166Tg(olig2:EGFP)vu12 fish (B) have an increased number of oligodendrocytes (green) in the grey matter of the spinal cord compared to WT (A). This is annotated by the EQE statement ?grey matter part_of spinal cord has extra parts of type oligodendrocyte?. In this annotation ?spinal cord? (ZFA:0000075) is post-composed with ?grey matter? (ZFA:0001681) to indicate that the phenotype is visible in the grey matter of the spinal cord; the PATO term used is relational which requires the use of a second entity term, in this case ?oligodendrocyte? (ZFA:0009076).