The elite athletic phenotype is a complex combination influenced by both multiple genes (polygenic) and environmental factors such as training and nutrition. Among single nucleotide polymorphisms (SNPs) associated with variation in physical traits, which are particularly important for performance in a variety of sports and with the elite athlete status, variants of PPAR (Peroxisome Proliferator-Activated Receptor) genes have emerged as crucial moderators that control the expression of genes encoding enzymes and other proteins involved in energy homeostasis (lipid and carbohydrate metabolism). Accumulated findings from studies showing that combinations of polymorphic markers located in PPAR genes are associated with increased/decreased performance raise the possibility that the PPAR gene variants are true performance enhancing polymorphisms (PEPs) that are believed to have a physiological impact on human body composition and metabolism. The aim of this review is to summarize the state of knowledge on the role of polymorphic variants of PPAR genes in physical performance or health related fitness phenotypes.
Introduction. The variance in human athletic ability is the result of interaction of both genetic and environmental factors. The ADRA2A gene that encodes adrenergic receptors α2 is likely to be a candidate gene because ADRA2A receptors are crucial for precise cardiovascular control and are involved in the regulation of adipocyte lipolysis, glucose metabolism and insulin secretion. Several genetic variants of the ADRA2A gene have been identified, and one nucleotide polymorphism (SNP) rs553668 seems to be of special importance. On the basis of results of available studies it is assumed that the C allele of rs553668 might be associated with the status of Polish elite endurance athletes. Aim of the Study. The purposes of the study were to determine the distribution of the ADRA2A rs553668 SNP genotypes within a sample of Polish elite endurance athletes and sedentary controls to investigate a possible association between genetic polymorphisms in the ADRA2A gene and elite endurance athlete status and to check for an association between the rs553668 genotypes and alleles and the athlete status. Material and Methods. The study was performed on a group of 123 elite Polish endurance-oriented athletes. Control samples were prepared from 228 unrelated, sedentary volunteers. Results. No statistical differences were found between the endurance athletes and the control group across the ADRA2A C/T genotypes. Similarly, no statistical differences among the subgroups of top-elite, elite and sub-elite endurance athletes were observed. Conclusions.We found that the C allele as well as C-containing genotypes were not significantly more frequent in endurance athletes than in controls. This may suggest that harboring the T allele of the SNP rs553668 allele does not decrease the probability of being an endurance-oriented athlete in the Polish population. In respect to the analyzed population of Polish endurance athletes the ADRA2A gene can not be considered a candidate determinant of individual variations in exercise-related phenotypes.