A gene at p23 on human chromosome 8 that controls prenatal neurogenesis. Null alleles of this gene cause homozygotes to have abnormally small heads and to be mentally retarded. This condition is called microcephaly (q.v.); the gene is named microcephalin, and its symbol is an abbreviation of this name. MCPH contains 14 exons, and the protein it encodes is composed of 835 amino acids. The protein (also called microcephalin) appears to function in DNA repair and to regulate chromosome condensation during the cell cycle. About 37,000 years ago, a neomorphic allele of MCPH arose, and this was subjected to such intense natural selection that it is now present in about 70 percent of present-day humans. See Appendix C, 2005, Lahn et al.; ASPM, neomorph.
Subjects: Genetics and Genomics.