Substitution of 2-Aminoadenine and 5-Methylcytosine for Adenine and Cytosine in Hybridization Probes Increases the Sensitivity of DNA Fingerprinting

An oligonucleotide (m⁵C-am²A-m⁵C)₅ containing 2′-amino-deoxyadenosine (am²A) and 5-methyldeoxycytidine (m⁵C) residues has been synthesized and compared with unsubstituted pentadecadeoxyribonucleotide (CAC)₅ as a hybridization probe for DNA fingerprinting. It was shown that considerably higher sensitivity can be achieved with the modified analog.     

Phosphodiesterase 4D (<Emphasis Type="Italic">PDE4D</Emphasis>) gene polymorphism in patients with acute stroke from Moscow

Two PDE4D gene polymorphisms [SNP41 (rs152312 and SNP87 (rs2910829)] were studied in patients with acute stroke (n = 577) and in control sample (n = 270). Significant differences in the genotype and allele frequency distribution were found between these samples for polymorphism SNP41. We showed that the AA and AG genotypes of SNP41 polymorphism were associated with higher risk of acute stroke development in the Moscow population (OR = 1.6). No association of SNP87 polymorphism with the disease was observed.     

<Emphasis Type="Italic">CYP2E1</Emphasis> gene polymorphism and ovarian cancer risk in the Yakut population

The CYP2E1 gene polymorphism has been studied in Yakut women with ovarian cancer and without cancer. The two groups have been found to substantially differ in the frequency of the CYP2E1*1D allele (with a 96-bp insertion in the promoter region of the gene): it is more frequent in healthy women (16.3 versus 7.4%, P = 0.007).     

Polymorphisms of DNA repair genes <Emphasis Type="Italic">ERCC</Emphasis>2 and <Emphasis Type="Italic">XRCC</Emphasis>1 in populations of Russia

We have conducted a comparative study of allele frequencies of single nucleotide polymorphisms (SNPs) rs1799793 and rs13181 of the ERCC2 gene as well as rs1799782 and rs25487 of the XRCC1 gene in population samples from European regions of Russia as well as in populations of Izhemski and Priluzski Komi and Yakuts. Significant differences in the distribution of polymorphic variants of the ERCC2 gene were demonstrated between populations of Yakuts and populations of Russians and Komi. In case of XRCC1 gene Izhemski Komi population exhibited dissimilar allele frequencies compared to other populations.     

p53 polymorphisms in Russia and Belarus: correlation of the 2-1-1 haplotype frequency with longitude

Four different polymorphisms in the human p53 gene (a 16-bp duplication in intron 3, and three RFLPs: for Bsh1236I at codon 72, for MspI in intron 6 and for BamHI in the 3 flanking region) and extended haplotypes were studied in nine geographically diverse populations from Russia and Belarus. The Yakuts differed from all other populations, as they had a significantly higher frequency of the BamHI A1 allele. Most populations did not differ significantly from each other in the frequency of the Bsh1236I polymorphism. The 16-bp duplication A1 allele and MspI A2 allele frequencies were significantly higher in the Yakut and Khant populations. Linkage disequilibrium values (D) between BamHI and other polymorphic sites were not significant in many cases; for this reason we have used the 16 bp–Bsh1236I–MspI haplotype frequencies only. Of eight possible haplotypes, five were observed in the populations investigated. Haplotype 1-2-2 was the most frequent in all populations. The next most common haplotype, 1-1-2, was present at very similar frequencies among the Byelorussians and Russians from Smolensk, but was more frequent in other populations. The frequency of haplotype 2-1-1 showed a nearly continuous decrease from West to East (from 17.857% among the Byelorussians to 0.685% in the Yakuts from the Verkhoyansk) and correlated with longitude (Spearmans r=–0.8667, P=0.0025), which may be due to natural selection and adaptation. The relationships among populations were evaluated by means of Neis D_A distances for the 16 bp–Bsh1236I–MspI haplotype frequencies. Based on the multidimensional scaling analysis a correlation between p53 haplotype frequencies and ethnicity is supposed.