MOXD2P (monooxygenase, DBH-like 2, pseudogene )

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Human Uniqueness Compared to "Great Apes": 
Likely Difference
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Monooxygenase, DBH-Like 2 (MOXD2) is a membrane associated monooxygenase that is expressed in the medial olphactory epithelium and is highly conserved in mammals. MOXD2 in human contains a deletion that removed the last two exons from the gene which resulted in its pseugenization in the human lineage. A polymorphic nonsense mutation also exists in the 6th exon of some humans. Loss of MOXD2 has been hypothesized to have altered smell sensitivity in humans.


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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Referenced By:
Topic Certainty
Sense of Smell Likely
Genetics Topic Attributes
Gene symbols follow the HUGO Gene Nomenclature Committee standard.
Gene Symbol Type of Human-Specific Changes
MOXD2 Pseudogenization, Exon Deletion


  1. Inactivation of MOXD2 and S100A15A by exon deletion during human evolution., Hahn, Y., Jeong S., and Lee B. , Mol Biol Evol, 10/2007, Volume 24, Issue 10, p.2203-12, (2007)