Sincepigisanimportantlivestockspeciesworldwide,itsgeneexpressionhasbeeninvestigatedintensively,butrarelyinbrain.Inordertostudygeneexpressionprofilesinthepigcentralnervoussystem,wesequencedandanalyzed43,122highquality5′endexpressedsequencetags(ESTs)fromporcinecerebellum,cortexcerebrum,andbrainstemcDNAlibraries,involvingseveraldifferentprenatalandpostnataldevelopmentalstages.TheinitialESTswereassembledinto16,101clustersandcomparedtoproteinandnucleicaciddatabasesinGenBank.Ofthesesequences,30.6%clustersmatchedproteindatabasesandrepresentedfunctionknownsequences;75.1%hadsignificanthitstonucleicaciddatabasesandpartialrepresentedknownfunction;73.3%matchedknownporcineESTs;and21.5%hadnomatchestoanyknownsequencesinGenBank.WeusedthecategoriesdefinedbytheGeneOntologytosurveygeneexpressionintheporcinebrain.