The brain was obtained from the adult specimens of the E. burgeri which were anesthetized by MS-222. The obtained tissues were frozen in liquid nitrogen, ground to a fine powder, and homogenized in TRIzol reagent (Invitrogen). Total RNA extraction was performed according to the provided protocol (Invitrogen). The extracted RNA sample was used for 454 library construction and sequencing, following protocols (Margulies et al., 2005).