Abstracts

Human Genome Diversity

Phenylketonuria (PKU) is a common autosomal recessive genetic disorder caused by a large variety of mutations in the phenylalanine hydroxylase (PAH) gene. The PAH gene contains multiallelic polimorfisms: VNTR - the 30bp AT-rich tandem repeats system located 3 kb downstream of the final exon of the PAH gene and STR - a series of short tandem (tetranucleotide, (TCTA)n) repeats in the third intron.

We have identified a distribution of frequencies of the VNTR and STR alleles within PAH gene in eight Volga-Ural populations for characterization of their genetics structure.

Seven different VNTR alleles were obtained in studied populations: 380, 440, 470, 500, 530, 560 and 650bp. The significant differences from the VNTR-allelic frequency distribution were found between all Volga-Ural populations. The 380bp allele was most frequent in all investigated populations studied (from 0,39 in Udmurts to 0,47 in Komies). The frequency of the 530bp allele ranged from 0,2 in Maries to 0,40 in Chuvashes. The uncommen 440bp and 470bp alleles found in one individual from the Bashkir sample and in some ndividuals from Bashkir, Tatars, Komies and Udmurts samples, respectively. An average level of the observed heterozygosity of VNTR loci in Volga-Ural populations was 71,3%.

Ten different STR alleles were obtained in populations of Volga-Ural region: 220, 228, 232, 236, 240, 244, 248, 252, 256 and 260 bp. The 244bp allele was most frequent in all investigated populations studied (from 0,32 in Bashkir and Mordvinians to 0,47 in Maries). The frequency of the 240bp allele ranged from 0,2 in Chuvashes and Udmurts to 0,33 in Komies. The 220bp alleles found in one individual from the Mordvinians, had not been described previously. The highest value of the observed heterozygosity of STR loci was typical for the Tatars (90%), while the lowest one was detected in the Mordvinians (70,2%).

The high index value of the observed heterozygosity of VNTR and STR systems along with the established differentiation of all investigated populations in respect to the frequency distribution of this alleles permitted the conclusion that the given polymorphic locies can serve as a highly informative marker for examination of the genetic structure of the Volga-Ural populations.

Note. Abstracts are published in author's edition

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