There are about 25,000 genes in the human genome, that is, 25,000 instructions for creating an acting and thinking body Of these, 858 describe the creation process of olfactory neurons — 3.5% of the chromosomal heritage is responsible for their creation. Of these, 468 are pseudogenes, their ancient functions disabled by some mutation that deprived them of the ability to synthesize proteins. This explains why humans, despite the fact that the sense of smell plays a strategic role in their lives, do not smell as keenly as other mammals.