A researcher from the University of Tokyo found that African elephants have the most olfactory receptor genes ever found in one species. The animal with the second most smell detectors was the cow, which still only had half the number of smell receptors.The author of the report, Yoshihito Niimura, also isolated three genes common to all the vertebrates in his sample, including humans.
He explained, “By comparing the differences in olfactory genes in different animals, we discovered which genes are common to all and which genes are unique to the animal. The common genes have been preserved throughout the evolutionary process and we think that these hold important functions for all types of animals. But for those genes which have increased specifically for the animal, we can infer that these are important genes for that animal in its specific environment.”
Two of the three shared genes have functions other than smell and appear in at least 16 organs in the human body.
African elephants have almost 2,000 different types of the smell gene in their trunks, more than twice the 811 smell genes found in dogs, and five times more than in humans who have about 400.
