ASPM (Genetics)

ASPM is a human gene whose defective forms are associated with autosomal recessive primary microcephaly. A new version of ASPM appeared about 5,800 years ago and has spread to half the world's population, especially Europe and West Asia.

"ASPM" is an acronym for " A bnormal Sp indle-like, M icrocephaly-associated", which reflects its being an ortholog to the Drosophila melanogaster "abnormal spindle" (asp) gene. ASPM is located on chromosome 1, band q31 (1q31).

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.

According to recent research regarding human evolution and cultural development, the most recent ASPM gene variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities. Currently, two variations of this gene exist: the older variation (pre-5,800 years ago) and the newer variation (post-5,800 years ago). About 10% of humans have two copies the "new" ASPM gene, while about 50% have two copies the "old" version. The other 40% of humans one copy of each. Of those with an instance of the new gene, 50% of them are a completely identical copy of the gene suggesting a highly rapid spread from the original mutation. According to evolutionary theory, the rapid spread of a mutation (such as the new ASPM) through the population indicates that the mutation is somehow advantageous to the individual. As of today, there is no evidence to support the notion that the new ASPM gene increases intelligence, and some researchers dispute whether the spread of the gene even demonstrates selection . However, statistical analysis has shown that the older forms of the gene are found more heavily in populations that speak tonal languages like Chinese. 

According to a follow-up study the ASPM gene has only found to be under selection in chinese people. The ASPM gene was not found to be under selection in Europeans or european derived populations (http://www.sciencemag.org/cgi/content/full/316/5823/370b) In the humane genome project (Hapmap) ASPM also was not found to be under selection in the Europeans.

References and notes

 * 1)  An IQ domain is a segment of DNA that codes for the IQ motif.
 * IQ protein motif: [FILV]Qxxx[RK]Gxxx[RK]xx[FILVWY]
 * The term "IQ" refers to the first two amino acids of the motif: isoleucine (commonly) and glutamine (invariably).
 * 1)  following is one of a large number of similar news articles:
 * 1)  following is one of a large number of similar news articles:
 * 1)  following is one of a large number of similar news articles: