Association of mitochondrial DNA haplogroups with endurance performance

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Leena Palotie auditorium 101A (Aapistie 5 A). Remote access: https://oulu.zoom.us/j/69281382975?pwd=WFF4R3ZObUVVMDRNa3hvcTJScEZSZz09

Topic of the dissertation

Association of mitochondrial DNA haplogroups with endurance performance

Doctoral candidate

Licentiate of Medicine , Master of Science Jukka Kiiskilä

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, Research Unit of Clinical Neuroscience

Subject of study

Neurology

Opponent

Professor Antti Sajantila, University of Helsinki

Custos

Professor Kari Majamaa, University of Oulu

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Association of mitochondrial DNA haplogroups with endurance performance

Proper mitochondrial function is a key determinant of endurance performance. Mitochondria are cell organelles which are responsible for cellular energy production through oxidative phosphorylation (OXPHOS). Previous research has indicated that variation in mtDNA affects endurance performance and a paucity of mtDNA haplogroup J and K has been detected among Finnish endurance athletes. This study showed that the association of mtDNA haploplogroups J and K with decreased endurance performance was present in the general population (p=0.041), although it was more apparent among the best-performing subjects that approach athletes with their endurance performance (p<0.001).

Haplogroups J and K were not characterized by the presence of excessive rare variation. Instead, the functional effect of these lineages might be related to some of the common nonsynonymous variants that define these haplogroups. Variant m.14798T>C in MTCYB is present in both haplogroups and, based on molecular modelling, it may hamper the function of complex III and cause redox imbalance. We found that the elevation in BCAA concentration was larger in subjects harboring haplogroups J and K than in subjects with non-JK haplogroups (p=0.029). The results suggest that BCAA catabolism is a surrogate marker of lower respiratory chain activity attributed to these haplogroups. It was also found, that rare mtDNA variants were more common among endurance athletes than sprinters or controls (p=0.04), suggesting that rare variation may contribute to endurance performance. The fact that two of the sprinters harbored disease-causing mtDNA variants may indicate that sprinters have a better tolerance for deleterious mutations than endurance athletes.

This dissertation was based on 3 scientific articles. The rate of functional variants and the mutational load was determined in mtDNA of Finnish athletes (n=141). The association of haplogroups J and K with physical performance was determined in a population-based cohort of 1,036 healthy Finnish men undergoing compulsory military service. Additionally, the effects of long-term exercise intervention on branched-chain amino acid (BCAA) catabolism were evaluated.
Last updated: 3.1.2022