 "Shh" cooperates with "dlx2" and "fezl" anteriorly and "IRX3" and "dbx1a" posteriorly (genes expressed vary among different organisms), which are genes that are expressed in the prethalamus and thalamus, respectively.The ZLI is also characterized by a lack of lunatic fringe ("lfng"), which is observable even before "Shh" expression is observed in the forming ZLI.This indicates that cells are fated for ZLI formation before induction by "Shh" (n.b.