Sense of smell, heredity and environment

The dependence of the sense of smell on familiar odors is shown

Oleg Lischuk, N+1

British, American and Brazilian scientists in experiments on mice found that olfactory perception is individual and is caused by both genetic factors and environmental conditions. The results of the work are published in the journal eLife (Ibarra-Soria et al., Variation in olfactory neuron repertoires is genetically controlled and environmentally modulated).

The olfactory analyzer significantly surpasses all others in the number of receptor types – for example, a mouse has more than a thousand of them, and each of about 10 million olfactory neurons expresses one type of these receptors. A separate smell stimulates a unique combination of receptors for it, which allows you to distinguish a wide range of olfactory stimuli and their shades. Due to the complexity of the analyzer device, how the sense of smell varies among different representatives of the same biological species, and what it depends on, has not been studied enough.

To understand this issue, the staff of the Sanger Institute with colleagues from other research centers used matrix RNA sequencing to quantitatively analyze each of the 1115 subtypes of olfactory neurons in genetically related and unrelated mice. Using the same technique, they assessed the effect on the composition of these neurons of the environment by adding various flavors to the drinking water of animals.

It turned out that the quantitative composition of neurons expressing different olfactory receptors differs significantly in different breeds of mice. At the same time, such differences are most controlled by genetic variants of regulatory elements of receptor genes and do not depend on the function of receptor proteins, the activity of olfactory neurons and their lifespan (olfactory neurons, unlike most others, are constantly updated).

It also turned out that the regular action of certain odors can, to a small but significant extent, affect the quantitative composition of olfactory neurons with different types of receptors. In particular, the number of neurons that perceive a familiar smell increases slightly due to a decrease in the number of neurons that remain unused in specific environmental conditions.

Drawing from the Wellcome Trust Sanger Institute press release
Genetics and environment combine to give everyone a unique sense of smell – VM

Thus, the quantitative composition of olfactory neurons and, consequently, sensitivity to specific odors depend both on genetics (to a greater extent) and on the environment (to a lesser extent), which forms an individual olfactory profile for each individual.

The results obtained can be used in personalized medicine, in particular, in the treatment of olfactory disorders. They also provide information about the organization and functioning of neurons. "The neurons of the olfactory system have many connections with other neurons of the brain, and their study can help in understanding the development of the nervous system," explained lead author Darren Logan (Darren Logan).

In recent years, various research teams have managed to show that olfactory receptors are present not only in the nasal mucosa, but also in other tissues of the body. So, they regulate the restoration of keratinocytes of the skin, sperm motility, proliferation of prostate cancer cells and hepatocarcinoma, as well as the tone of smooth muscle cells of the bronchi.

Portal "Eternal youth" http://vechnayamolodost.ru  25.04.2017