MCPH1 (microcephalin 1)

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MCPH-1 is a DNA damage response protein. Inactivation of the MCPH1 gene in humans results in a severe condition called microcephaly, i.e. a small brain, associated with mental retardation. As human evolution is characterized by a marked increases in brain size, one group evaulated this gene and reported that it had undergone significantly higher rates of protein sequence evolution in primates than in rodents. Furthermore, they reported that the gene has undergone even more rapid evolution in humans, including evidence of a selective sweep in human populations. However, several aspects of the latter findings have been debated by other groups. Regardless, it is interesting that a gene that is associated with a small brain when it is damaged in humans, may have also shown increased evolution in humans.

Genetics Topic Attributes
Gene symbols follow the HUGO Gene Nomenclature Committee standard.
Gene Symbol Type of Human-Specific Changes
MCPH1 Accelerated Evolution


  1. Comment on "Ongoing adaptive evolution of ASPM, a brain size determinant in Homo sapiens" and "Microcephalin, a gene regulating brain size, continues to evolve adaptively in humans"., Currat, Mathias, Excoffier Laurent, Maddison Wayne, Otto Sarah P., Ray Nicolas, Whitlock Michael C., and Yeaman Sam , Science, 2006 Jul 14, Volume 313, Issue 5784, p.172; author reply 172, (2006)
  2. Microcephalin, a gene regulating brain size, continues to evolve adaptively in humans., Evans, Patrick D., Gilbert Sandra L., Mekel-Bobrov Nitzan, Vallender Eric J., Anderson Jeffrey R., Vaez-Azizi Leila M., Tishkoff Sarah A., Hudson Richard R., and Lahn Bruce T. , Science, 09/2005, Volume 309, Issue 5741, p.1717-20, (2005)
  3. Reconstructing the evolutionary history of microcephalin, a gene controlling human brain size., Evans, P. D., Anderson J. R., Vallender E. J., Choi S. S., and Lahn B. T. , Hum Mol Genet, 01/2004, Volume 13, Issue 11, p.1139-45, (2004)