OCLN (Occludin)

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Human Uniqueness Compared to "Great Apes": 
Likely Difference
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Occludin (OCLN) is a four transmembrane domain protein in the tight junction complex of polarized epithelial cells. It regulates paracellular permeability, cell adhesion, and has been shown to mediate hepatitis C entry into human liver cells. Humans have a pseudogene located 1.5 Mb away from this gene that is not present in other primates. Due to variability in the copy number of this pseudogene across human populations, it has been hypothesized that this pseudogene may play a role in susceptibility to infection of Hepatitis C.


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
OCLN Copy Number Changes


  1. Population-genetic properties of differentiated human copy-number polymorphisms., Campbell, Catarina D., Sampas Nick, Tsalenko Anya, Sudmant Peter H., Kidd Jeffrey M., Malig Maika, Vu Tiffany H., Vives Laura, Tsang Peter, Bruhn Laurakay, et al. , Am J Hum Genet, 03/2011, Volume 88, Issue 3, p.317-32, (2011)
  2. Diversity of human copy number variation and multicopy genes., Sudmant, Peter H., Kitzman Jacob O., Antonacci Francesca, Alkan Can, Malig Maika, Tsalenko Anya, Sampas Nick, Bruhn Laurakay, Shendure Jay, and Eichler Evan E. , Science, 10/2010, Volume 330, Issue 6004, p.641-6, (2010)
  3. Identification of human specific gene duplications relative to other primates by array CGH and quantitative PCR., Armengol, Gemma, Knuutila Sakari, Lozano Juan-José, Madrigal Irene, and Caballín María-Rosa , Genomics, 2010 Apr, Volume 95, Issue 4, p.203-9, (2010)
  4. Human occludin is a hepatitis C virus entry factor required for infection of mouse cells., Ploss, Alexander, Evans Matthew J., Gaysinskaya Valeriya A., Panis Maryline, You Hana, de Jong Ype P., and Rice Charles M. , Nature, 02/2009, Volume 457, Issue 7231, p.882-6, (2009)
  5. Lineage-specific gene duplication and loss in human and great ape evolution., Fortna, A., Kim Y., MacLaren E., Marshall K., Hahn G., Meltesen L., Brenton M., Hink R., Burgers S., Hernandez-Boussard T., et al. , PLoS Biol, 07/2004, Volume 2, Issue 7, p.E207, (2004)