Mitochondrial DNA (mtDNA) polymorphisms are associated with longevity in the Guangxi Bama population of China. Xiurong Yang, Xinping Wang, Huilu Yao, Jixian Deng, Qinyang Jiang, Yafen Guo, Ganqiu Lan, D. Joshua Liao, and Hesheng Jiang conducted a study and received it on 22 November 2011. It was accepted on 9 June 2012, and published online on 24 June 2012 by Springer Science+Business Media B.V. Total cholesterol, triglycerides, and low-density lipoprotein levels were lower in mt146C individuals than in mt146T individuals in the older age group (P < 0.05). However, no significant differences were observed between the mt146C and mt146T individuals in the middle and younger age groups (P > 0.05). The mt5178C/A polymorphisms did not show any significant differences among the three age groups (P > 0.05), but different nationalities in the Bama County showed a significant difference in the mt5178C/A polymorphisms (P < 0.05). These results suggest that the mt146T/C polymorphisms in Guangxi Bama individuals may partly account for Bama longevity whereas the mt5178C/A polymorphisms are strongly associated with nationalities in the Guangxi Bama population.

Abstract: Human longevity is an interesting and complicated subject with many associated variations such as geographic and genetic variations including mitochondrial variations. The population of Bama County of Guangxi Province of China is well-known for its longevity and serves as a good model for studying potential molecular mechanisms. In this study, a full sequence analysis of mitochondrial DNA (mtDNA) was done on ten Bama centenarians using direct sequencing. Polymorphisms of the displacement loop (D-loop) region of mtDNA and several serum parameters were analyzed for a total of 313 Bama individuals aged between 10 and 110 years. The results showed that there were seven mitochondrial variations: A73G, A263G, A2076G, A8860G, G11719A, C14766T, and A15326G, and four haplogroups: M*, F1, D*, and D in 10 Bama centenarians. In the D-loop region 4 of mtDNA, mt146T occurred at a significantly lower frequency in older age groups (90-110 years) than in the middle (80-89 years) and younger (10-79 years) groups (P < 0.05). The mt146T also had lower systolic blood pressure and serum markers such as total cholesterol, triglycerides, and low-density lipoprotein than did mt146C in the older age group (P < 0.05). However, no significant differences were observed between the mt146C and mt146T individuals in the middle and younger groups (P > 0.05). The mt5178C/A polymorphisms did not show any significant differences among the three age groups (P > 0.05), but different nationalities in Bama County showed a significant difference in the mt5178C/A polymorphisms (P < 0.05). These results suggest that the mt146T/C polymorphisms in Guangxi Bama individuals may partly account for Bama longevity whereas the mt5178C/A polymorphisms are strongly associated with nationalities in the Guangxi Bama population.

Introduction: Mitochondria are cellular organelles responsible for ATP synthesis, heat production, radical oxygen species (ROS) generation, fatty acid and steroid metabolism, cellular apoptosis, etc. Because of their critical role in energy production, mitochondria have been the focus of studies on the mechanism for longevity. Mitochondria have their own genetic material, mtDNA, a circular double-stranded molecule of 16,569 bp encoding two tRNAs, two rRNAs, and 13 proteins. Since mtDNA is maternally inherited and females have a longer lifetime than males in various species, mtDNA has been suggested to play an important role in the process of aging and longevity.

Huilu Yao, Jixian Deng, and Hesheng Jiang from China-ASEAN (Guangxi) Biotechnology Cooperative Center, Guangxi Academy of Sciences, Nanning 530003, Peoples Republic of China conducted this study. There is geographical variation in numerous mtDNA inherited variants, some of which have been reported to affect the aging process. Different populations are expected to have different gene-longevity associations. There is evidence that mitochondrial bioenergetics contribute to longevity and the mitochondrial theory of aging suggests that a progressive accumulation of somatic mutations leads to a decline in mitochondrial function. Previous studies suggest that a variety of deletions and mutations accumulate with age in mtnormal distribution using the Kolmogorov-Smirnov test. The data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test for multiple comparisons. Statistical significance was set at P < 0.05. All statistical analyses were performed using SPSS version 19.0 software (IBM Corporation, Armonk, NY, USA).Hardy-Weinberg equilibrium. Statistical analyses were performed using SAS statistical software version 8.02. The Pearson v2 test was used to analyze the genotype frequencies among the three age groups. Serum parameters were analyzed using the least square means calculated from the general linear regression model (GLM) procedure.

Results

Full mitochondrial DNA sequence in Guangxi Bama Centenarians

The full mtDNA samples of 10 Guangxi Bama centenarians were sequenced using the PCR-based approach as shown in Table 5. 

Mitochondrial D-loop SNPs in Guangxi Bama populations

Locus SNPs 90110 8089 1079 (n = 113) (n = 75) (n = 125) 
282 W T 99.12 89.33 96.00 
M1 A 0.88 8.00 3.20 
M2 C 0.00 2.66 0.80 
298 W C 97.35 94.67 92.80 
M1 T 2.65 1.33 4.00 
M2 A 0.00 4.00 3.20 
310 0 28.32 42.67 34.40 
INS C 71.68 57.33 65.60 
311 0 85.84 90.67 80.80 
INS C 14.16 9.33 19.20 
318 O* O* O* 
INS C** C** C**