High Frequency of Ancestral Haplotype A of Fatty Acid Desaturase Genes in the Yakut Population.

Aims: The purpose of this study was to study the correlation of the body weight of Yakuts with the variability of polymorphisms rs174537, rs174546 and rs3834458 of the FADS1 - FADS2 region to identify the connection of certain genotypes with obesity. Materials and Methods: For genotyping, classical methods of PCR-RFLP analysis were used. A sample of 446 DNA samples from Yakut volunteers without chronic diseases (143 women and 303 men) was studied. Results: The predominance of the ancestral alleles of SNPs rs174537, rs174546 and rs3834458 was established in all of our studied groups. Analysis of the odds ratio of allele and genotype frequencies in patients with normal BMI, high BMI and obesity did not show statistically significant values. We did not find an association between rs174537, rs174546 and rs3834458 with obesity, but we did not take into account the diet of the subjects, which may have had a stronger effect on BMI. Analysis of pairwise linkage disequilibrium and assessment of haplotypes for 3 SNPs in the FADS1 and FADS2 genes showed strong linkage of all three SNPs to each other (r2 = 0.93-0.96). Conclusions: According to the result of genotyping of SNP rs174537, the frequency of haplotype A in the Yakut population was 0.76 and, in comparison with other world data, is quite high. Which in turn is associated with lower conversion of short-chain polyunsaturated fatty acid to long-chain polyunsaturated fatty acid. Accordingly, a shift in nutrition towards more plant foods can negatively impact the health of the Yakuts. At the moment, the exact dosage of polyunsaturated fatty acids (PUFAs) for humans has not yet been established, but judging by the fact that all recommendations are mainly made on the basis of European populations, in connection with the results of the study, the Yakuts have a particularly high need for PUFAs.

FADS1 gene polymorphism(s) and fatty acid composition of serum lipids in adolescents.

Polyunsaturated fatty acids (PUFA) influence many physiological functions. Associations have been found between single nucleotide polymorphisms (SNP) in the FADS1 (Fatty acid desaturase 1) gene and the relative abundance of PUFA in serum lipids. This study examines the relationship between two SNPs in the FADS1 gene (rs174546, rs174537) and the fatty acid (FA) composition of serum lipids in adolescents (13-18 years). We used DNA samples (670 children; 336 girls and 334 boys) from the Childhood Obesity Prevalence and Treatment (COPAT) project. Genomic DNA was extracted from peripheral blood leukocytes in whole blood samples. For genotype analysis, TaqMan SNP Genotyping assays (Applied Biosystems) were used. Fatty acid composition of serum lipids was assessed using gas chromatography. The T-statistic and regression were used for statistical evaluations. Minor allele T carriers in both SNPs had significant lower level of palmitic acid (16:0, phospholipids) and arachidonic acid (20:4[n-6], phospholipids) in both sexes. In girls, we found a significant positive association between minor allele T carriers and eicosadienoic acid (20:2[n-6], cholesteryl esters) in both SNPs. Being a minor allele T carrier was significantly positively associated with dihomo-γ-linolenic acid (20:3[n-6], phospholipids) in boys in both SNPs. SNPs (including rs174546, rs174537) in the FADS gene cluster should have impacted desaturase activity, which may contribute to different efficiency of PUFA synthesis.