C20orf203 (chromosome 20 open reading frame 203)

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Human Uniqueness Compared to "Great Apes": 
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C20orf203 is a de novo human gene that evolved from non-coding DNA after the split between human and chimp. In the human lineage 5 point mutations in the region resulted in the creation of an open reading frame which lead to the expression and translation of 194 amino acid (22kDa) protein. This protein is enriched in the brain and is up regulated in the brains of Alzheimer’s patients and thus has been hypothesized to play a role in the pathogenesis of this disease.


Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

Definite Appearance: 
6,000 thousand years ago
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Genetics Topic Attributes
Gene symbols follow the HUGO Gene Nomenclature Committee standard.
Gene Symbol Type of Human-Specific Changes
C20orf203 De Novo Human Gene


  1. A human-specific de novo protein-coding gene associated with human brain functions., Li, Chuan-Yun, Zhang Yong, Wang Zhanbo, Zhang Yan, Cao Chunmei, Zhang Ping-Wu, Lu Shu-Juan, Li Xiao-Mo, Yu Quan, Zheng Xiaofeng, et al. , PLoS Comput Biol, 2010 Mar, Volume 6, Issue 3, p.e1000734, (2010)