Emx1 and Emx2 are human homologs to the Drosophila developmental genes empty spiracles expressed in anterior body regions during early Drosophila embryogenesis. Emx1 and Emx2 are homeobox proteins expressed in the developing vertebrate brain. Emx2 is expressed in the dorsal telencephalon and small diencephalic regions, while Emx1 expression is exclusively confined to pyramidal neurons of the dorsal telencephalon. In the embryonic brain, Emx1 is expressed in both proliferating and differentiating neurons while Emx2 is expressed only in proliferating neurons. OTX1 and OTX2 are human homologs of the Drosophila developmental genes orthodenticle. In development, the sequence of expression begins with OTX2 at day 10 post coitum followed by OTX1, Emx2 and finally Emx1. The genes encoding human Emx1 and Emx2 map to chromosomes 2p14-p13 and 10q26.1, respectively.