MT-ND5 and myopia: Interestingly, eight out of nine variants were predominantly located in related sub-haplogroups, and especially rs1603221206 in CO2 and rs1556424337 in ND5 showed strong linkage with the sub-haplogroup D4a3b, while rs1603223649 in tRNALeu (CUN) and rs1556424843 in D-loop also showed strong linkage within the sub-haplogroup G2a4 (Table 2; Fig. 3B), indicating that the sub-haplogroup background can increase the susceptible risk for high myopia like in the other disease.