Microcephalin: Difference between revisions
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==Evolution== |
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| author = Evans, P.D., ''et al.'' |
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| doi = 10.1073/pnas.0610848104 |
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⚫ | Haplogroup D may have originated from a lineage separated from modern humans approximately 1.1 million years ago and later introgressed into humans. This finding supports the possibility of admixture between modern humans and extinct ''[[archaic Homo sapiens|Homo]]'' spp. ([[Neanderthal]]s being one possibility).<ref>[http://www.pnas.org/cgi/content/abstract/0606966103v1 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</ref> On the other hand the sample of 89 individuals with only 9 Africans used in the study has been criticized as being inadequate for the conclusion the paper draws, and comparable studies demostrate that undersampling specific areas of East/Central Africa may lead to unwarranted conclusions.<ref name="pmid17175528">{{cite journal |author=Shimada MK, Panchapakesan K, Tishkoff SA, Nato AQ, Hey J |title=Divergent haplotypes and human history as revealed in a worldwide survey of X-linked DNA sequence variation |journal=Mol. Biol. Evol. |volume=24 |issue=3 |pages=687-98 |year=2007 |pmid=17175528 |doi=10.1093/molbev/msl196 |issn=}}</ref> |
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== Expression in the brain == |
== Expression in the brain == |
Revision as of 19:40, 23 June 2007
microcephaly, primary autosomal recessive 1 | |||||||
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Identifiers | |||||||
Symbol | MCPH1 | ||||||
NCBI gene | 79648 | ||||||
HGNC | 6954 | ||||||
OMIM | 607117 | ||||||
UniProt | Q8NEM0 | ||||||
Other data | |||||||
Locus | Chr. 8 p23 | ||||||
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microcephaly, primary autosomal recessive 2 | |
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Identifiers | |
Symbol | MCPH2 |
NCBI gene | 4181 |
HGNC | 6955 |
OMIM | 604317 |
Other data | |
Locus | Chr. 19 q13.1-13.2 |
microcephaly, primary autosomal recessive 3 | |
---|---|
Identifiers | |
Symbol | MCPH3 |
Alt. symbols | CDK5RAP2 |
NCBI gene | 23702 |
HGNC | 6956 |
OMIM | 604804 |
Other data | |
Locus | Chr. 9 q33.3 |
microcephaly, primary autosomal recessive 4 | |
---|---|
Identifiers | |
Symbol | MCPH4 |
NCBI gene | 23701 |
HGNC | 6957 |
OMIM | 604321 |
Other data | |
Locus | Chr. 15 q15-21 |
microcephaly, primary autosomal recessive 5 | |
---|---|
Identifiers | |
Symbol | MCPH5 |
Alt. symbols | ASPM |
NCBI gene | 64590 |
HGNC | 6958 |
OMIM | 608716 |
Other data | |
Locus | Chr. 1 q31 |
microcephaly, primary autosomal recessive 6 | |
---|---|
Identifiers | |
Symbol | MCPH6 |
Alt. symbols | CENPJ |
NCBI gene | 170629 |
HGNC | 17120 |
OMIM | 608393 |
Other data | |
Locus | Chr. 13 q12.2 |
Microcephalin (Greek for "small head) is a gene associated with brain size.[1][2] Its name comes from the fact that a mutation in any of the six copies (called MCPH1 to MCPH6) of the gene may cause microcephaly (Online Mendelian Inheritance in Man (OMIM): 251200), a condition characterised by a severely diminished brain.[3][4]
Evolution
A derived form of MCPH1 called haplogroup D appeared 37,000 years ago and has spread to become the more common form throughout the world except Sub-Saharan Africa. The timing of its emergence narrowly preceded the Upper Paleolithic, when people started colonising Europe.[5] The distribution of chromosomes bearing the ancestral forms of MCPH1 and MCPH5 coincide with the incidence of tonal languages, although the exact nature of the relationship is unknown.[6]
Haplogroup D may have originated from a lineage separated from modern humans approximately 1.1 million years ago and later introgressed into humans. This finding supports the possibility of admixture between modern humans and extinct Homo spp. (Neanderthals being one possibility).[7] On the other hand the sample of 89 individuals with only 9 Africans used in the study has been criticized as being inadequate for the conclusion the paper draws, and comparable studies demostrate that undersampling specific areas of East/Central Africa may lead to unwarranted conclusions.[8]
Expression in the brain
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.
Other names
The microcephaly-related genes MCPH 3, 5 and 6 are usually called classified as their alternate names CDK5RAP2, ASPM and CENPJ, according to their other roles. More information can be found from the links in the information boxes.
Sources and notes
- ^ Wang, Y.Q. & B. Su (2004). "Molecular evolution of microcephalin, a gene determining human brain size". Hum. Mol. Genet. 13: 1131–1137. doi:10.1093/hmg/ddh127.
- ^
Evans, P.D.; et al. (2004). "Reconstructing the evolutionary history of microcephalin, a gene controlling human brain size". Hum. Mol. Genet. 13: 1139–1145. doi:10.1093/hmg/ddh126.
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Jackson, A.P.; et al. (1998). "Primary Autosomal Recessive Microcephaly (MCPH1) Maps to Chromosome 8p22-pter". Am. J. Hum. Genet. 63: 541–546. PMID 9683597.
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Jackson, A.P.; et al. (2002). "Identification of Microcephalin, a Protein Implicated in Determining the Size of the Human Brain". Am. J. Hum. Genet. 71: 136–142. PMID 12046007.
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Evans, P.D.; et al. "Microcephalin, a gene regulating brain size, continues to evolve adaptively in humans". Science. 309: 1717–20. doi:10.1126/science.1113722.
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(help) - ^ Dediu, D. & D.R. Ladd (2007). "Linguistic tone is related to the population frequency of the adaptive haplogroups of two brain size genes, ASPM and Microcephalin". Proc. Nat. Acad. Sci. doi:10.1073/pnas.0610848104.
- ^ 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
- ^ Shimada MK, Panchapakesan K, Tishkoff SA, Nato AQ, Hey J (2007). "Divergent haplotypes and human history as revealed in a worldwide survey of X-linked DNA sequence variation". Mol. Biol. Evol. 24 (3): 687–98. doi:10.1093/molbev/msl196. PMID 17175528.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
External links
- Neanderthal Brains - a lecture by Bruce Lahn - from the NYAS podcasts.