ASPM

ASPM is a human gene (locus 1q31) associated with autosomal recessive primary microcephaly.

The ASPM gene is the human ortholog of the Drosophila melanogaster "abnormal spindle" (asp) gene.

The mouse gene Aspm is expressed in the primary sites of prenatal cerebral cortical neurogenesis. The difference between Aspm and ASPM is a single, large insertion coding for so-called IQ domains. Here the letters I and Q refer to amino acids (Isoleucine and Glutamine).¹

Footnote

1. An IQ domain is a segment of DNA that codes for the IQ motif: :[FILV]Qxxx[RK]Gxxx[RK]xx[FILVWY]

The first letter is frequently an I, and the second is always Q, and hence the name, IQ motif. See DNA motif for further details about the notation.