Microcephalin
From Wikipedia, the free encyclopedia
Microcephalin (from Greek "small head") is a human gene linked to brain size. Its functions are still being discovered by scientists worldwide.[1] One type, Microcephalin 1 (MCPH1), has been linked to recent human evolution, and might have originally appeared among Neanderthals.
MCPH1 "regulates brain size during development and has experienced positive selection in the lineage leading to Homo sapiens."[2] "Within modern humans, a group of closely related haplotypes at this locus, known as haplogroup D, rose from a single copy approx 37,000 years ago and swept to exceptionally high frequency (approx 70% worldwide today) because of positive selection. [...] Haplogroup D likely originated from a lineage separated from modern humans approx 1.1 million years ago and introgressed into humans by approx 37,000 years ago. This finding supports the possibility of admixture between modern humans and archaic Homo populations (Neanderthals being one possibility)."[3]
MCPH1 is not evenly distributed across the globe. It occurs most often in European, East Asian, and certain South American Indian populations.[4][5]
MCPH1 is expressed in the fetal brain, in the developing forebrain, and on the walls of the lateral ventricles. Cells of this area divide, producing neurons that migrate to eventually form the cerebral cortex. This gene (MCPH1) is on chromosome 8 in the region known as 8p23. Microcephalin (MCPH1) is also the first gene identified among about six locations that contribute to the autosomal recessive disease primary microcephaly.[1]
Microcephalin is listed at the National Center for Biological Information's (NCBI) PopSet website under the classification numbers 46358778, 46358718, 46325692, 46325560, 46325428, 46325296, 46325236, 46325104, 46324972, 46324840, 46276730, 46276598, 46276466, 37529583, and 37529501.[6]
Contents |
[edit] ASPM
ASPM is another gene linked to recent evolution of the human brain.
[edit] Sources and notes
- ^ a b see further reading
- ^ Patrick D. Evans. "Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage
- ^ PNAS article Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage Published online before print November 7, 2006 by Proceedings of the National Academy of Sciences of the USA
- ^ [1]
- ^ [2]
- ^ National Center for Biological Information PopSet for Microcephalin
[edit] External links
- Neanderthal Brains - a lecture by Bruce Lahn - from the NYAS podcasts.
