Genes differentially expressed between parthenogenetic and androgenetic embryos are candidates for the identification of imprinted genes, which are expressed specifically from the maternal or paternal allele. To search for genes differentially expressed between parthenogenetic and androgenetic embryos, we used the RIKEN full-length enriched mouse cDNA microarray. The 25 candidates obtained included 8 known imprinted genes (such as IgtfII, Snrpn, and Neuronatin) and 3 new ones-Asb4 (ankyrin repeat and SOCS box-containing protein 4), Ata3 (amino acid transport system A3), and Decorin-which were confirmed by using normal diploid embryos from the reciprocal F1 crosses of B6 and JF1 mice. The 25 candidates also included genes that showed no imprinting-associated expression in normal diploid embryos. We describe a feasible high-throughput method of screening for novel imprinted genes by using the RIKEN cDNA microarray. (C) 2002 Elsevier Science (USA).