Genetic basis of olfactory cognition: extremely high level of DNA sequence polymorphism in promoter regions of the human olfactory receptor genes revealed using the 1000 Genomes Project dataset.
The molecular mechanism of olfactory cognition is very complicated. Olfactory cognition is initiated by olfactory receptor proteins (odorant receptors), which are activated by olfactory stimuli (ligands). Olfactory receptors are the initial player in the signal transduction cascade producing a nerve impulse, which is transmitted to the brain. The sensitivity to a particular ligand depends on the expression level of multiple proteins involved in the process of olfactory cognition: olfactory receptor proteins, proteins that participate in signal transduction cascade, etc. The expression level of each gene is controlled by its regulatory regions, and especially, by the promoter [a region of DNA about 100-1000 base pairs long located upstream of the transcription start site (TSS)]. We analyzed single nucleotide polymorphisms using human whole-genome data from the 1000 Genomes Project and revealed an extremely high level of single nucleotide polymorphisms in promoter regions of olfactory receptor genes and HLA genes. We hypothesized that the high level of polymorphisms in olfactory receptor promoters was responsible for the diversity in regulatory mechanisms controlling the expression levels of olfactory receptor proteins. Such diversity of regulatory mechanisms may cause the great variability of olfactory cognition of numerous environmental olfactory stimuli perceived by human beings (air pollutants, human body odors, odors in culinary etc.). In turn, this variability may provide a wide range of emotional and behavioral reactions related to the vast variety of olfactory stimuli.
Laboratory of Evolutionary Bioinformatics and Theoretical Genetics, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences Novosibirsk, Russia ; Department of Natural Science, Novosibirsk State University Novosibirsk, Russia.
Elena V
EV
Ignatieva
Department of Natural Science, Novosibirsk State University Novosibirsk, Russia ; Laboratory of Molecular-Genetic Systems, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences Novosibirsk, Russia.
Victor G
VG
Levitsky
Department of Natural Science, Novosibirsk State University Novosibirsk, Russia ; Laboratory of Human Molecular Genetics, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences Novosibirsk, Russia.
Nikolay S
NS
Yudin
Department of Natural Science, Novosibirsk State University Novosibirsk, Russia ; Laboratory of Mammalian Ecological Genetics, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences Novosibirsk, Russia.
Mikhail P
MP
Moshkin
Department of Natural Science, Novosibirsk State University Novosibirsk, Russia ; Department of Systems Biology, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences Novosibirsk, Russia ; National Research centre "Kurchatov Institute" Moscow, Russia.
Nikolay A
NA
Kolchanov
1000 Genomes Project; olfactory cognition; olfactory receptor gene; promoter; single nucleotide polymorphism