Genetical background of intelligence

Abstract

Intelligence as an ability to reason, think abstractly and adapt effectively to the environment is a subject of research in the field of psychology, neurobiology, and in the last twenty years genetics as well. Genetical testing of twins carried out from XX century indicated heritebility of intelligence, therefore confirmed an influence of genetic factor on cognitive processes. Studies on genetic background of intelligence focus on dopaminergic (DRD2, DRD4, COMT, SLC6A3, DAT1, CCKAR) and adrenergic system (ADRB2, CHRM2) genes as well as, neutrofins (BDNF) and oxidative stress genes (LTF, PRNP). Positive effect of investigated gene polymorphism was indicated by variation c.957C>T DRD2 gene (if in polymorphic site is thymine), polymorphism c.472G>A COMT gene (presence of adenine) and also gene ADRB2 c.46A->G (guanine), CHRM2 (thymine in place c.1890A>T) and BDNF (guanine in place c.472G>A) Obtained results indicate that intelligence is a feature dependent not only on genetic but also an environmental factor.

Longitudinal genetic studies of cognitive characteristics

“…Quantitative measurements of DNA methylation in the promoter regions of the dopamine D4 receptor (DRD4), serotonin transporter (SLC6A4) and monoamine oxidase A (MAOA) genes were performed using DNA samples of 46 pairs of monozygotic and 45 dizygotic twins aged 5 to 10 years (Wong et al, 2010). The association of gene alleles and cognitive abilities was identified (Owens et al, 2012;Junkiert-Czarnecka, Haus, 2016). It was found that differences in DNA methylation appeared even in early childhood in genetically identical individuals and were unstable with time.…”

Genetic Mechanisms of Cognitive Development

“…The study of the role of the genetic component in individual differences in intelligence are focused on the genes belonging to the family of neurotrophins (BDNF), oxidative stress (LTF, PRNP), and adrenergic (ADRB2, CHRM2) and dopaminergic systems (DRD2, DRD4, COMT, SLC6A3, DAT, CCKAR). The associations with allelic variant c.957C>T in the DRD2 gene, c.472G>A in the COMT gene, c.46A>G in the ADRB2 gene, c.1890A>T in the CHRM2 gene, and c.472G>A in the BDNF gene were detected [4]. The allelic variants of the genes encoding cholinergic receptor nicotinic alpha 7 subunit (CHRNA7, 15q14), dopamine receptor type 4 (DRD4, 11p15.5), dopamine transporter (SLC6A3, 5p15.33), and monoamine oxidase А (МАОА, Xp11.3) were associated with attention.…”

“…The g factor is a key construct in differential psychology, behavioral genetics, and cognitive neuroscience [2]. Twin, family, and adoption studies demonstrated that the g factor was highly inherited and genetically stable throughout life [3,4].…”

Accelerated Variability of Human Genes and Transportable Elements; Genesis of Network

“…Accelerated regions (HARs) are conservative genomic loci with increased divergence in humans. Using sequencing of chromatin interaction, massively parallel reporter assays (MPRA) and transgenic mice, authors of article [55] identified disease-related biallelic mutations of HARs in the active enhancers for CUX1, PTBP2, GPC4, CDKL5 and other genes involved in neural function. Authors of review [9] listed HARs associated genes involved in the evolution and function of the brain: AUTS2, NPAS3, FZD8, CUX1, PTBP2, and GPC4.…”

“…Authors of review [9] listed HARs associated genes involved in the evolution and function of the brain: AUTS2, NPAS3, FZD8, CUX1, PTBP2, and GPC4. We could not find a match between these genes and 52 intelligence genes listed in the studies [13] and [55] and we did not compare with a set of 939 genes in the article [56]. SNP has a special role in human evolution and disease.…”