Methods are provided for identification of genes that are imprinted. In another embodiment methods are provided for identification and analysis of genes whose expression shows allelic imbalance. The expression products transcribed from genes that are present in the genome as two or more alleles may be distinguished by hybridization to an array designed to interrogate individual alleles. Genes whose transcription products are present in amounts that vary from expected are candidates for allelic imbalance, imprinting and imprinting errors.