Project Director

Kovach, Margaret

Department Examiner

Wilson, Thomas; Spratt, Henry; Kutz, Douglas

Department

Dept. of Biological and Environmental Sciences

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Growing evidence suggests that genetic variants of certain genes are linked to athletic performance. This study presents a comparative analysis of genetic variation of the ACE and ACTN3 genes in varsity athletes (n=90) and sedentary students (n=48) at the University of Tennessee at Chattanooga. The ACE gene codes for the Angiotensin Converting Enzyme (ACE), which is an integral part of the Renin-Angiotensin system. It is responsible for regulating blood volume,arterial pressure, electrolyte balance, and cardiac and vascular function.Polymorphisms of the ACE gene effect serum and tissue levels of the enzyme, and are genetically distinguished by either an insertion (I-allele) or deletion (D-allele) of an alu repeat within intron 16. The Insertion allele is thought to be beneficial to endurance athletes. On the other hand, the ACTN3 gene encodes the 901 amino acid alphaactinin- 3 protein found only in Type II (Fast-Twitch) muscle fibres. Its function is to provide structural support for the transmission of force during muscle contraction along the Z line and sustain the order of myofilaments and coordinate myofilament contraction (Yang et. al, 2003). The polymorphisms identified in exons 15 and 16 are thought to be important to ACTN3 gene function. Although not clearly shown to be linked to athletic performance, a point mutation in exon 15 of the A CTN3 gene introduces an Arginine(R)➔ Glutamine(Q) substitution at amino acid residue 523 (designated R523Q) with possible functional implications. A stronger correlation exists for genetic variants involving mutations in exon 16 of the ACTN3 gene. A polymorphism in exon 16 manifests as a premature stop codon,2 Arginine(R)➔ Stop(X) at position 577 of the protein (R577X). The R allele of Exon16 is thought to be advantageous to athletes that require short and forceful bursts of power due to full-length and functional ACTN3 proteins. Each sample was scored for the ACE and ACTN3 genotypes and data was analyzed in a population of 90 UTC athletes and 48 sedentary controls by PCR and RFLP analysis. Results:The genotypic frequencies of the ACE gene deviated from the Hardy Weinberg Equilibrium whereas exons 15 and 16 of the ACTN3 gene did not. The I allele of the ACE gene was observed in a notably increased frequency amoung endurance athletes (24.1%) when compared to the non-endurance athletes (7.9%) and the sedentary group (12.5%). There were no significant differences between the athletes ( endurance or non-endurance) and the control subjects with respect to exon 15 of the ACTN3 gene. The frequency of the 577R allele of exon 16 was found to be significantly higher amoung UTC athletes(58.5%)than in the sedentary students(36.5%). In addition, there was a linear increase in the 577R allele from the sedentarygroup(36.5%), endurance athletes (55.6%),and non-endurance athletes (61.4%).Conclusion: The ACE 1/D and ACTN3 polymorphisms have been related to athletic performance in elite athletes. This project examined an athlete population at the NCAA Division I level. Both of the favourable variants of these polymorphismswere observed in this project.It can be concluded that I allele of the ACE gene occurs at a greater frequency in endurance athletes when compared to non-endurance athletes and sedentary subjects. In addition, the 577R allele in exon 16 of the ACTN3 3 gene is found in an increased frequency in athletes and specifically non-endurance athletes when compared to the sedentary subjects. Furthermore, these results are consistent with previous studies of elite and Olympic caliber athletes and support the hypothesis that the I allele of the ACE gene is beneficial to endurance athlete whereas the 577R allele of the ACTN3 gene is advantageous to non-endurance athletes.

Acknowledgments

I would like to thank Dr. Kovach for being my project director and Dr. Spratt, Dr. Wilson, and Dr. Kutz for being on my committee. I would like to thank Dr. Barlow for her assistance in the lab, Dr. Wilson for his guidance with the statistical analysis, and Todd Bullard and the Athletic Training Department for their cooperation with this project.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

3-2006

Subject

Athletic ability--Testing; Ability--Genetic aspects; College athletes--Tennessee--Chattanooga

Discipline

Genetics

Document Type

Theses

Extent

65 leaves

DCMI Type

Text

Language

English

Call Number

LB2369.5 .M396 2006

Rights

http://rightsstatements.org/vocab/InC/1.0/

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