Olfactory Receptors

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Human Uniqueness Compared to "Great Apes": 
Absolute Difference

The olfactory receptor (OR) gene family contains approximately 1000 genes for olfaction, and humans have experienced varying lineage-specific alterations in these genes. Of the ~1000 genes within the family, over 60% are pseudogenized in humans, a percentage twice as high as other non-human primates, and many OR genes have undergone lineage-specific conversion events affecting odorant binding sites. Additionally, humans have accumulated mutations four times faster in these genes than other primates. One example of this phenomenon is the OR gene 912-93, which in humans has experienced a nonsense mutation rendering it nonfunctional. In contrast to this general pattern of loss/pseudogenization, a DNA segment containing multiple OR genes has expanded from 1-2 copies in chimpanzee and gorilla to 7-11 copies in humans.

The Human Difference: 

Gene duplication

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Sense of Smell True


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