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Cortical Thrombospondin Expression

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Human Uniqueness Compared to "Great Apes": 
Likely Difference
MOCA Domain: 
Neuroscience
MOCA Topic Authors: 
Todd M Preuss

Expression of THBS2 and THBS4 genes and protein in adult frontal cortex increased in human evolution. Thrombospondins are proteins that promote the formation of synapses.  Increased expression of thrombospondins in the frontal cortex of humans, compared to other primates including chimpanzees, has been demonstrated with microarrays, PCR, Western blotting and immunohistochemistry.

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Timing

Timing of Appearance of the Difference in the Hominin Lineage.

For this entry assume that

  • the common ancestor of humans and old world monkeys was 25000 thousand (25 million) years ago
  • the common ancestor of humans and chimpanzees was 6000 thousand (6 million) years ago
  • the emergence of the genus Homo was 2000 thousand (2 million) years ago
  • the common ancestor of modern humans was 100 thousand years ago

 

Possible Appearance: 
6000 Thousand Years
Definite Appearance: 
100 Thousand Years
Background Information: 

Expression of THBS2 and THBS4 genes and protein in adult frontal cortex increased in human evolution. The thrombospondins are proteins that promote the formation of synapses. Comparative microarray studies of gene expression indicate that THBS4 and THBS2 are expressed at higher levels in the cortex of humans compared to chimpanzees and other nonhuman primates. These results were confirmed using PCR with samples from prefrontal and temporal cortex. Western blotting with antibodies for THBS4 and THBS2 protein also demonstrated higher expression in humans, and immunohistochemistry for THBS4 in prefrontal cortex yielded much stronger labeling of the neuropil in humans than in chimpanzees or macaques (Cáceres et al., 2007).

References: 

Cáceres M, Suwyn C, Maddox M, Thomas JW, Preuss TM (2007) Increased cortical expression of two synaptogenic thrombospondins in human brain evolution. Cereb Cortex 17:2312-2321 [Epub 2006 Dec 2320].Christopherson KS, Ullian EM, Stokes CC, Mullowney CE, Hell JW, Agah A, Lawler J, Mosher DF, Bornstein P, Barres BA (2005) Thrombospondins are astrocyte-secreted proteins that promote CNS synaptogenesis. Cell 120:421-433.Preuss TM, Cáceres M, Oldham MC, Geschwind DH (2004) Human brain evolution: insights from microarrays. Nat Rev Genet 5:850-860.