In human, ZIM2 and PEG3 (GeneID:5178) are two distinct genes that share a set of 5' exons and have a common promoter, and both genes are paternally expressed. Alternative splicing events connect the shared exons either with the remaining 4 exons unique to ZIM2, or with the remaining 2 exons unique to PEG3. This is in contrast to mouse and cow, where ZIM2 and PEG3 genes do not share exons in common, and the imprinting status of ZIM2 is also not conserved amongst mammals. Additional 5' alternatively spliced transcripts encoding the same protein have been found for the human ZIM2 gene. [provided by RefSeq, Oct 2010]