International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Genetics, demography, anthropology

The architecture of linkage disequilibrium in the human genome is now subject of brisk discussions and intensive research. The analysis of linkage disequilibrium can give the new information on human origin and evolution, and also to discover the population and demographic scenarios observed in a history of gene pool formation in various populations.

In this study we investigated genotype and haplotype frequencies, and a linkage of three SNPs, localized in the multidrug resistance gene (MDR1). The multidrug resistance gene (MDR1) encodes transmembrane P-glycoprotein, providing transfer from a cell outside of a wide spectrum of substances (xenobiotics, medicinal preparations, peptides, virus particles). The size of a gene is 210 kb, it contains 30 exons. Several studies show involvement of this gene in resistance to infections; therefore, polymorphism in a gene MDR1 can have adaptation value.

Three SNPs were selected as markers: C3435T, -1G/A and +139C/T. For a material of research was three samples: Russians from Tomsk (90); Tuvinians from Bai-Taiga, republic Tuva (142); Kirghizes southern from Kirghizia (44), Kirghizes northern from Kirghizia (41). The genotypes were determined with the use of polymerase chain reaction and restriction fragment length polymorphism.

Results: the C3435T and +139C/T loci for all four populations have high level of polymorphism (Hobs from 0,43 up to 0,50 except +139C/T in southern Kirghizes Hobs=0,23). For a -1G/A locus in all samples the low level of polymorphism (Hobs from 0,00 for Tuvinians up to 0,03 for Russian) was observed.

The haplotypes distribution was similar – sum of haplotypes C3435, -1G, +139C; 3435T, -1G, 139C and 3435T, -1G, +139T frequencies varied from 82 % for Tuvinians up to 99 % for northern Kirghizes. The number of haplotypes among the investigated populations differed from 4 for Tuvinians up to 7 for Russians. The linkage between C3435T and +139C/T loci among Russians and southern Kirghizes populations was detected. The genotype distribution conformed to the Hardy – Weinberg equilibrium with a significance level 0,95 for all samples and all loci.

Conclusions: the frequencies of alleles in C3435T, -1G/A and +139C/T loci among the researched populations are within the framework of world frequencies, the presence of linkage between C3435T and +139C/T loci is conform to the data on “block like” structure of linkage disequilibrium and existence of “hotspots” of recombination, as in case of uniform recombination the probability of linkage between +139C/T and -1G/A loci would be higher, than between С3435Т and +139C/T loci, because the distance between them is 34kb and 57kb accordingly.

Note. Abstracts are published in author's edition

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Last update: 06-Jul-2012 (11:52:05)