AQP7 (aquaporin 7)

Certainty Style Key
Hover over keys for definitions:
True   Likely   Speculative
Human Uniqueness Compared to "Great Apes": 
Likely Difference
MOCA Domain: 
MOCA Topic Authors: 

The AQP7 gene shows a human lineage-specific (HLS) copy number increase in humans compared to great apes, monkeys, and prosimians. This copy number increase (at least 5 copies in humans vs. 1-3 in chimpanzees and other apes) was detected by cDNA array-based comparative genomic hybridization (Fortna et al. 2004). Aquaporins are thought to play a key role in water transport across membranes (Preston et al. 1992), and of the eight aquaporin family members assayed, the only one that showed an HLS copy number increase was AQP7 (Dumas et al. 2007; Fortna et al. 2004). AQP7 is also an aquaglyceroporin, and in addition to water, AQP7 is also capable of transporting glycerol, an energy storage molecule. Most of the AQP7 copies map to the pericentromeric region of chr 9, one of the most evolutionarily dynamic regions of the human genome and the location of the greatest concentration of HLS gene copy number increases (Dumas et al. 2007; Fortna et al. 2004). The HLS increase in copy number of AQP7 is a candidate to play a role in thermoregulation (sweating) and energy mobilization (via glycerol transport) from fat to muscle, adaptations that may have contributed to the enhanced capacity for endurance running found in humans (Dumas et al. 2007; Bramble and Lieberman 2004).

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Genetics Topic Attributes
Gene symbols follow the HUGO Gene Nomenclature Committee standard.
Gene Symbol Type of Human-Specific Changes
AQP7 Copy Number Changes
Timing

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 currently defined as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25000 thousand (25 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6000 thousand (6 million) years ago
  • the emergence of Homo ergaster was 2000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 400 thousand years ago
  • the common ancestor of modern humans was 100 thousand years ago

Probable Appearance: 
5,000 Thousand Years
Definite Appearance: 
2,000 Thousand Years
The Human Difference: 

Types of Human-Specific Changes in AQP7:

Copy Number Variation

Accelerated evolution

References

  1. Gene copy number variation spanning 60 million years of human and primate evolution., Dumas, L., Kim Y. H., Karimpour-Fard A., Cox M., Hopkins J., Pollack J. R., and Sikela J. M. , Genome Res, 09/2007, Volume 17, Issue 9, p.1266-77, (2007)
  2. 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)
  3. Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein., Preston, G M., Carroll T P., Guggino W B., and Agre P , Science, 1992 Apr 17, Volume 256, Issue 5055, p.385-7, (1992)