semmelweis university - Faculty of Physical Education and Sport ...

Eri Mikami-Noriyuki Fuku-Takahashi Hideyuki
Waseda University Tokyo Metropolitan Institute of Gerontology
Japan Institute of Sports Sciences
Supervisor: Masashi Tanaka, professor
Mitochondrial Haplogroups Associated with Elite Japanese Athlete Status
Background: Because mitochondrial DNA (mtDNA) encodes 13 proteins essential to
oxidative phosphorylation, it is a candidate to contain variants influencing physical
performance. Mitochondrial haplogroups, which are defined by the presence of characteristic
clusters of tightly linked mtDNA polymorphisms, are reported to be associated with elite
athlete status in Europeans [1, 2] and Africans [3]. Mitochondrial haplogroup distributions
display geographical diversity; indeed almost all mitochondrial haplogroups in Africans and
Europeans are not present in Asians including Japanese. The purpose of the present study was
to examine the association between mitochondrial haplogroups and elite Japanese athlete
status.
Methods: Subjects comprised 139 Olympic-standard Japanese athletes (79 endurance/middlepower
athletes: EMA, 60 sprint/power athletes: SPA) and 672 Japanese controls (CON) from
the mtSNP database (http://mtsnp.tmig.or.jp/mtsnp/index_e.shtml). The fragments of mtDNA
containing the hypervariable sequence I (m.16024 – m.16383) and three protein-coding
regions (subunit 2 and 5 of NADH dehydrogenase and cytochrome b) were sequenced.
Subjects were classified into 12 major haplogroups (i.e., F, B, A, N9a, N9b, M7a, M7b, M*,
G2, G1, D5, and D4). Haplogroup frequency differences between EMA and CON, and
between SPA and CON were examined by Chi-square tests. For haplogroup analysis, each
haplogroup versus the sum of all other haplogroups was compared.
Results&discussion: EMA showed an excess of haplogroup G1 (odds ratio: 2.52 [95%
confidence interval: 1.05-6.02], p=0.032), with 8.9% compared to 3.7% of CON, whereas
SPA displayed a greater proportion of haplogroup F (odds ratio: 2.79 [95% confidence
interval: 1.28-6.07], p=0.007), with 15% relative to 6% of CON. According to sequecnces of
the protein-coding region of mtDNA, EMA-related haplogroup G1 is characterized by two
polymorphisms: m.15323G>A and m.15497G>A. These polymorphisms cause Ala193Thr
and Gly251Ser replacements in the cytochrome b, which is a subunit of the Complex III.
SPA-related haplogroup F is also characterized by a polymorphism: m.13928G>C. This
polymorphism causes a Ser531Thr replacement in the NADH dehydrogenase subunit 5,
which is a component of the Complex I. It is possible that these amino acid replacements
might influence the functions of cytochrome b and NADH dehydrogenase subunit 5,
contributing positively to endurance/middle-power and sprint/power performance in Japanese,
respectively.
Conclusion: Our results suggest that mitochondrial haplogroups G1 and F are associated with
elite endurance/middle-power and sprint/power athlete status in Japanese, respectively and
may implicate the functional polymorphisms identified.
Reference:
1. Niemi AK, Majamaa K. Mitochondrial DNA and ACTN3 genotypes in Finnish elite
endurance and sprint athletes. Eur J Hum Genet 2005;13:965-9.
2. Castro MG, Terrados N, Reguero JR, et al. Mitochondrial haplogroup T is negatively
associated with the status of elite endurance athlete. Mitochondrion 2007;7:354-7.
3. Scott RA, Fuku N, Onywera VO, et al. Mitochondrial haplogroups associated with elite
Kenyan athlete status. Med Sci Sports Exerc 2009;41:123-8.
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