Order and transcription direction (arrows) of SIBLING genes plus adjacent PKD2 and SPARCL1 genes in mammals, green anole, and chicken. Note that the order of the DSPP and DMP1-like genes are reversed between mammals and the anole without changing their direction of transcription relative to the surrounding genes. Row labeled ChickenA is our interpretation of the relative directions of all six genes' transcription as based on the version 2.1 chicken genome from the Genome Sequencing Center at the Washington University School of Medicine (St. Louis, MO) as compared to the interpretation by Sire et al.  (ChickenB).
McKnight and Fisher BMC Evolutionary Biology 2009 9:299 doi:10.1186/1471-2148-9-299