title: [Analysis of polymorphism of CTG repetitive sequences in the gene of myotonic dystrophy in human populations of the Volga-Ural region].
abstract: Distribution of CTG repetitive sequences in the myotonic dystrophy (MD) gene was analyzed in ten populations of the Volga-Ural region, including Tatars, Chuvashes, Maris, Udmurts, Mordovians, Komis, and four ethnogeographical groups of Bashkirs. A total of 25 alleles were found (9 to 14 in individual populations), with each allele containing 5 to 34 trinucleotide repeats. The allele frequency distribution had two peaks corresponding to alleles with 5 and 11-14 CTG repeats. The frequency of the (CTG)5 allele varied from 0.23 to 0.47 in Maris and Mordovians, respectively. Regarding the (CTG)11-14 alleles, those containing 13 and 12 trinucleotides were most frequent in all populations; their frequencies varied from 0.15 in Mordovians to 0.24 in Maris and Bashkirs from the Abzelilovskii raion (district). Alleles with large numbers of repeats (more than 30) were only found in Tatars and Bashkirs from the Abzelilovskii raion, where their frequency was 0.01. The data obtained were compared with those on other human populations from various regions of the world. In general, the populations of the Volga-Ural region took an intermediate position between European and Asian populations (although were somewhat more similar to the latter ones) with respect to the distribution of allelic frequencies of the CTG repetitive sequences. In individual populations, the number of genotypes varied from 13 to 27 in Mordovians and Bashkirs from the Ilishevskii raion, respectively. The observed heterozygosity was the highest (91%) in Udmurts and the lowest (58%) in Mordovians; the average heterozygosity was 81%. Such a high heterozygosity, as well as the revealed differentiation of the populations with respect to the distribution of the allelic frequencies of CTG repetitive sequences in the MD gene, allow this polymorphic DNA locus to be considered a highly informative genetic marker of populations.
authors.affiliation: Department of Biochemistry and Cytochemistry, Ufa Research Center, Russian Academy of Sciences, Russia.
authors.forename: R I
authors.initials: RI
authors.lastname: Fatkhlislamova
authors.forename: I M
authors.initials: IM
authors.lastname: Khidiatova
authors.forename: E K
authors.initials: EK
authors.lastname: Khusnutdinova
authors.forename: S N
authors.initials: SN
authors.lastname: Popova
authors.forename: P A
authors.initials: PA
authors.lastname: Slominskiĭ
authors.forename: S A
authors.initials: SA
authors.lastname: Limborskaia
mesh_terms: D005006:Ethnicity / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D008297:Male; D009223:Myotonic Dystrophy / Q000235:genetics*; D011110:Polymorphism, Genetic; D011159:Population Surveillance; D012426:Russia; D018911:Trinucleotide Repeats
chemical_list: D005819:Genetic Markers