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About how many working olfactory receptor genes do humans have?
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Senses
Vespid wasps (Vespidae), similar to other insects, have compound eyes that consist of thousands of tiny optical units known as ommatidia, which contain light-sensitive photoreceptor cells.
Humans possess approximately 1,000 olfactory receptor genes, which constitute the largest known family of genes in the human genome. However, only about 350 of these genes are functional and encode working olfactory receptors.1
The remaining majority of these genes are nonfunctional pseudogenes. In humans, as well as in Old World monkeys and great apes, as many as 70 percent of these olfactory receptor genes are considered nonfunctional. Evidence suggests that the pool of these pseudogenes in humans is increasing, which indicates that the human sense of smell may become further reduced in the future.2