Genetic markers for resistance athletes to physical loads
1. State scientific institution “Institute of genetics and Cytology of NAS of Belarus”; 2. RSPC “Mother and child” MOH; 3. Si “Republican centre of sports medicine,” the MCIT Republic of Belarus; 4. The Ministry of sport and tourism of the Republic of Belarus
The body’s response to physical activity is of particular importance for the organization of training process and competition practice of sportsmen of high qualification. Installed hereditary factors, providing quick and adequate responses to physical activity. Hypoxia is one of the leading factors limiting athletic performance in almost all cyclical and in most team sports.
The aim of this work was to establish the frequencies of allelic variants of genes present in the genotypes of elite athletes, to identify the most informative markers defining the type, the severity and persistence of adaptive responses to short-term and prolonged hypoxia. In this regard, we have tested DNA samples of members of the National teams of Belarus, biathlon and ice hockey as potential carriers of the most favorable genotypes.
Biathlon is a cyclical sport, which requires mainly aerobic endurance. In hockey dominates power-speed focus and athletes to predominantly anaerobic type of physical exercise. Given the different type of endurance athletes of these sports, the determination and comparison of frequencies of genes present in the genotype, will identify the most important and most informative alleles, providing a record of the resistance to hypoxia, and as a consequence, to physical stress.
Materials and methods
To test for resistance to hypoxia we sampled 10 polymorphic variants in 8 genes encoding proteins directly involved in the body’s reaction to lack of oxygen.
We analyzed DNA samples from the national teams of Belarus biathlon team (18 persons) and hockey (42 people). As a control, studied the DNA of people not professionally involved in sports (150 people). Biological material for research served as DNA extracted from peripheral blood leukocytes.
Molecular genetic analysis genomic DNA of athletes made by the method of polymerase-tion chain reaction (PCR). To identify each gene polymorphisms used Dupri-dimensional system. After amplification of specific DNA sequences of genes for the identification of alleles of the polymorphisms was performed using different methodological approaches.
For analysis of polymorphism I/D of ACE gene, +9/-9 BDKRB2 gene and 4A/L eNOS gene used the method of direct determination of the difference in electrophoretic mobility of DNA fragments in lucellino gel.
Alleles of polymorphisms A79G gene MB and G298T eNOS gene were identified by the presence or absence of restriction site after treatment of the PCR products corresponding endonucleases and electrophoretic separation in polyacrylamide or agarose gels.
The definition of polymorphism 4G/5G in the gene PAI-1 was performed using automated capillary electrophoresis in a genetic analyzer ABI PRISM 310.
Identification of single nucleotide substitutions in the genes of HIF1 A, EPO and VEGF were performed by the method of re-sequencing.
Results and discussion lSeHHIFl.
The lack of oxygen leads to activation of the HIF1 gene AND that in turn triggers expression of hypoxia-dependent genes ACE, eNOS, PAI-1, BDKRB2, EPO,VEGF and ENDT-1. In the gene there is significant polymorphism — S/T. its Prevalence in the European population of 9-10%. According to [ 1 ] polymorphism C/T associated with high aerobic capacities. When testing the national teams of rare variants G polymorphism 588G/A provides a much higher level of synthesis Spadge under normal oxygen concentrations, were identified in one of the chromosomes in three of 18 biathlon (17%) and in 11 of the 42 players (25%). In the DNA sample of one athlete, one player found the T allele of the polymorphism C/T, which also gives a high level of HIF1 and is associated with high aerobic capacities . The discovery of these rare polymorphisms in elite athletes indicates a higher stability of their media to physical activity and the importance of this marker for the selection of athletes.
2. Genes determining factors of adaptation to hypoxia cardiovascular system.
ACE is an enzyme of the renin-angiotensin and kallikrein-kinin systems — humoral regulators of blood pressure . Polymorphism of ACE gene is associated with the insertion (I) or deletion (D) 287 nucleotides . Genotype i/l ACE gene is associated with reduced concentration of the enzyme and provides 7-8 times greater physical performance and better adaptation of the organism to trenirovka than genotype D/D. the Frequency of occurrence of the genotype of ACE gene II the inhabitants of the European countries ranges from 16% to 24% . The distribution of genotypes and alleles for the ACE group of Belarusian sportsmen of high qualification are presented in table 1.
The results of testing athletes of the highest caliber we did not reveal significant compared with the population frequency of prevalence of the preferred option (i/l as alle La I in both groups. Obviously, the contribution of ACE gene in resistance to hypoxia is not determinative.
eNOS catalyzes the reaction of formation of nitric oxide (N0) from L-arginine. In the study of polymorphisms 4A/G and G/T (tab. 1) among athletes revealed a significant excess frequency of favorable genotypes and alleles compared to unfavorable, indicating the importance of these polymorphisms for adaptation to hypoxia.
BDKRB2 encodes (32-receptor of bradykinin , is a powerful vasodilator. In BDKRB2 gene us /insertion (-9/+9), which is associated with a high level of gene expression, increased glucose metabolism in the muscle, increased production of N0. According to  -9/-9 among Belarusian sportsmen of cyclic and mixed sports meets at 26.8%, and in controls (persons not engaged in professional
sports) and 15.3% . Our results are presented in table 1.
Table 1. The frequencies of genotypes and alleles determining factors of adaptation of the cardiovascular system to hypoxia (bold options, where the frequency of favorable genotypes significantly greater than the frequency of adverse.