𝘼𝘾𝙀 Genetic Polymorphism and Body Composition Characteristics in Collegiate Runners

Abstract

Background and Objectives: Contemporary sports science recognized that sports performance is determined by a complex interaction among environmental conditions, training status, and genetic factors. Among the genetic markers that have received considerable attention, the Angiotensin-converting enzyme (ACE) gene is one of the most extensively studied genetic markers in sports. It plays a crucial role in the renin-angiotensin system, which regulates cardiovascular homeostasis. The ACE Insertion/Deletion (I/D) polymorphism arises from the presence (Insertion, I) or absence (Deletion, D) of a 287-base pair sequence within intron 16 on chromosome 17, and this variation can influence ACE enzyme activity in the body. Previous studies have demonstrated an association between the ACE I/D polymorphism and athletic physical performance; the I allele tended to correlate with endurance-oriented traits and muscle fatigue resistance, whereas the D allele was frequently associated with power, strength, and muscle hypertrophy. However, most studies of ACE genotypes have focused on elite athletes or non-Thai populations, leaving the genetic profile of Thai collegiate runners unexplored. Accordingly, this study aimed to examine the genotype distribution of the ACE gene in regularly trained university runners and to explore its relationship with body composition.

Methodology: This study used a cross-sectional design and involved 24 runners from Burapha University, consisting of 18 males and 6 females, with a mean age of 20.17 ± 1.24 years. All participants were regularly trained university runners. Body composition was assessed using bioelectrical impedance analysis to obtain body mass index (BMI), percent body fat, and skeletal muscle mass. DNA samples were collected from buccal epithelial cells using buccal swabs and subsequently extracted using a DNA extraction kit. The ACE I/D genotype was analyzed via polymerase chain reaction (PCR) utilizing gene-specific primers. The resulting PCR products were separated by agarose gel electrophoresis to visualize genotype patterns. To confirm the accuracy of genotype identification, nucleotide sequencing was performed. Genotype frequencies were tested for Hardy–Weinberg equilibrium (HWE), and the associations between ACE genotype and body composition variables were analyzed using non-parametric statistical techniques appropriate for small sample sizes, with the Kruskal–Wallis H test at a significance level of 0.05. Descriptive statistics were reported as mean ± standard deviation, while genotype distribution was expressed as frequency and percentage.

Results: The results revealed that the ACE genotype distribution in Thai collegiate runners deviated from the Hardy-Weinberg equilibrium. The heterozygous ID genotype was observed most frequently, accounting for 75.0% of the sample, while both homozygous II and DD genotypes were found in equal proportions of 12.5% each. Statistical analysis revealed no significant differences in BMI, body fat percentage, or skeletal muscle mass among the genotype groups (p > 0.05). However, the descriptive results showed a consistent trend. The II genotype group exhibited the highest mean values for BMI, percent body fat, and skeletal muscle mass, followed by the DD group, and then the ID group. These findings suggest that while no significant association was detected in this relatively small sample, genotype-related tendencies may still exist and warrant further investigation in larger populations.

Conclusions: In conclusion, Thai collegiate runners showed an unusually high frequency of the ACE ID genotype. This specific genotype may represent a genetic profile that confers advantages in training adaptations, competition, or overall athletic performance at the university level. Although no statistically significant associations between ACE genotype and body composition were detected, the II genotype group showed a tendency toward greater BMI, adiposity, and skeletal muscle mass. These findings highlight the importance of conducting population-specific genetic studies among Thai athletes, as such information may contribute to a better understanding of sport-related genetic variation. In the future, larger and more diverse samples will be necessary to clarify the biological and performance-related roles of the ACE I/D polymorphism. Ultimately, this line of research may support the development of personalized training and conditioning programs to individual genetic profiles, thereby enhancing athletic preparation and performance optimization.