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Enterovirus (EV) 71 caused episodes of outbreaks in China and Southeast Asia during the last few decades. We have previously reported that EV71 induces reactive oxygen species (ROS). However, the underlying mechanism remains elusive. Co-immunoprecipitation-proteomic analysis revealed that enteroviral 2B protein interacted with mitochondrial voltage-dependent anion channel 3 (VDAC3). Knockdown (KD) of VDAC3 expression specifically inhibited enteroviral replication. Single-round viral replication was also inhibited in KD cells, suggesting that VDAC3 plays an essential role in replication. Consistent with this, VDAC3 gene KD significantly reduced the EV71-induced mitochondrial ROS generation. Exogenous 2B expression could induce the mitochondrial ROS generation that was significantly reduced in VDAC3-KD cells or in the Mito-TEMPO-treated cells. Moreover, VDAC3 appears to be necessary for regulation of antioxidant metabolism. VDAC3 gene KD led to the enhancement of such pathways as hypotaurine/taurine synthesis in the infected cells. Taken together, these findings suggest that 2B and VDAC3 interact to enhance mitochondrial ROS generation, which promotes viral replication. [ABSTRACT FROM AUTHOR]

Mitochondrial genomes of vascular plants are well known for their liability in architecture evolution. However, the evolutionary features of mitogenomes at intra-generic level are seldom studied in vascular plants, especially among gymnosperms. Here we present the complete mitogenome of Cycas debaoensis, an endemic cycad species to the Guangxi region in southern China. In addition to assemblage of draft mitochondrial genome, we test the conservation of gene content and mitogenomic stability by comparing it to the previously published mitogenome of Cycas taitungensis. Furthermore, we explored the factors such as structural rearrangements and nuclear surveillance of double-strand break repair (DSBR) proteins in Cycas in comparison to other vascular plant groups. The C. debaoensis mitogenome is 413,715 bp in size and encodes 69 unique genes, including 40 protein coding genes, 26 tRNAs, and 3 rRNA genes, similar to that of C. taitungensis. Cycas mitogenomes maintained the ancestral intron content of seed plants (26 introns), which is reduced in other lineages of gymnosperms, such as Ginkgo biloba, Taxus cuspidata and Welwitschia mirabilis due to selective pressure or retroprocessing events. C. debaoensis mitogenome holds 1,569 repeated sequences (> 50 bp), which partially account for fairly large intron size (1200 bp in average) of Cycas mitogenome. The comparison of RNA-editing sites revealed 267 shared non-silent editing site among predicted vs. empirically observed editing events. Another 33 silent editing sites from empirical data increase the total number of editing sites in Cycas debaoensis mitochondrial protein coding genes to 300. Our study revealed unexpected conserved evolution between the two Cycas species. Furthermore, we found strict collinearity of the gene order along with the identical set of genomic content in Cycas mt genomes. The stability of Cycas mt genomes is surprising despite the existence of large number of repeats. This structural stability may be related to the relative expansion of three DSBR protein families (i.e., RecA, OSB, and RecG) in Cycas nuclear genome, which inhibit the homologous recombinations, by monitoring the accuracy of mitochondrial chromosome repair. [ABSTRACT FROM AUTHOR]

The rusty grain beetle, Cryptolestes ferrugineus (Stephens), is a serious pest of stored grain, which has developed high levels of resistance to phosphine. In this study, five geographically distant populations of C. ferrugineus had been collected in China, specifically in granaries where phosphine fumigant is used for pest control, and they showed a high resistance ratio up to 1,907 (LC50 = 21.0 mg/liter). Then, a reference transcriptome was constructed to use as a basis for investigating the molecular mechanisms of phosphine resistance in this species, which consisted of 47,006 unigenes with a mean length of 1,090. Subsequently, the RNA-Seq analysis of individuals from the most susceptible and resistant populations led to the identification of 54 genes that are differentially expressed. GO and KEGG analysis demonstrated that genes associated with mitochondrial and respiration functions were significantly enriched. Also, the 'structural constituent of cuticle' term was annotated in the GO enrichment analysis and further qRT-PCR confirmed that the expression levels of nine cuticular protein genes were significantly increased in the resistant population. In conclusion, we present here a transcriptome-wide overview of gene expression changes between resistant and susceptible populations of C. ferrugineus , and this in turn documents that mitochondria and cuticular protein genes may play together a crucial role in phosphine resistance. Further gene function analysis should enable the provision of advice to expedite resistance management decisions. [ABSTRACT FROM AUTHOR]

Panax ginseng C. A. Meyer (Araliaceae) root and leaf have always been considered in the traditional theory as hot and cold properties, respectively. To clarify the hot and cold properties of ginseng root and leaf from a thermodynamic viewpoint. Thirty ICR male mice were randomly assigned to control (water), ginseng root group (GRP) and ginseng leaf group (GLP) with a concentration of 0.075 g/mL; the volume was 0.1 mL/10 g (body mass) per day by intragastric administration for 20 days. Ultra-Performance Liquid Chromatography (UPLC) was used to determine quality control through seven ginsenosides contained in ginseng root and leaf. Rest metabolic rate (RMR) and energy expenditure were monitored every 9 days by TSE System. At the 20th day, serum T3 or T4, liver or brown adipose tissue (BAT) mitochondrial respiration were investigated. The quality control of GRP and GLP were within requirements of 2015 China Pharmacopoeia. The RMR (mLO2/h) in GLP (47.95 ± 4.20) was significantly lower than control (52.10 ± 4.79) and GRP (55.35 ± 4.48). Mitochondrial protein concentration and respiration were significantly increased in GRP (BAT, 79.12 ± 2.08 mg/g, 239.89 ± 10.24 nmol O2/min/g tissue; Liver, 201.02 ± 10.89, 202.44 ± 3.24) and decreased in GLP (BAT, 53.42 ± 3.48, 153.49 ± 5.58; Liver, 138.69 ± 5.69, 104.50 ± 6.25) compared with control. The hot and cold properties of ginseng root and leaf are correlated with thermogenic capacity and mitochondrial function of BAT and liver, which deserve to further research. [ABSTRACT FROM AUTHOR]

The wild albino northern snakehead, Channa argus, has only been found in Jialing Rivers System of China so far. It is easy to be affected by the environmental factors such as temperature changes and bacterial infection, thus causing a huge economic loss. Therefore, this study cloned a 2,213 bp cDNA that encodes a protein of heat shock protein 70 (CaHSP70), which has an open reading frame (ORF) that encodes 639 amino acids and the corresponding polypeptides of 70.50 kDa. And the oretical isoelectric point (pI) of CaHSP70 is 5.79. Additionally, we also cloned a cDNA for heat shock cognate protein 70 (CaHSC70) with a total length of 2,300 bp. And the ORF of CaHSC70 encodes 648 amino acids and 71.18 kDa peptides. The pI of CaHSC70 is 5.22. Moreover, the cDNA length of stress-70 protein mitochondrial (CaHSPA9) is 2,944 bp with an ORF that encodes 679 amino acids, polypeptides of 73.74 kDa, and a pI of 6.68. The quantitative real-time PCR (qRT-PCR) analysis showed that the mRNA expression levels of CaHSP70 , CaHSC70 , and CaHSPA9 genes were tissue-specific in the control groups. After the heat shock at 37 °C, the mRNA expression levels of CaHSP70 were extremely significantly upregulated in the kidney, liver, spleen, and brain tissues, while fewer mRNA expression levels of Ca HSC70 and CaHSPA9 showed a relatively induction in these tissues. In contrast, after the cold shock at 8.5 °C, fewer mRNA expression levels of CaHSP70, CaHSC70, and CaHSPA9 showed the changes of expression in all the tissues, compared to heat shock. In addition, CaHSP70 , CaHSC70 , and CaHSPA9 mRNA expression levels showed an overall trend of first upregulating and then falling after Edwardsiella tarda (strain No. DL1,476) challenge. In conclusion, this study demonstrated that temperature had a great effect on the mRNA expression levels of CaHSP70 , CaHSC70 , and CaHSPA9 , and the mRNA expression levels of these three genes were also sensitive to pathogen infection, especially CaHSP70 in the albino C. argus. • The full-length cDNAs of CaHSP70, CaHSC70, and CaHSPA9 were first cloned and characterized in the albino Channa argus. • The mRNA expression levels of CaHSP70 , CaHSC70 , and CaHSPA9 were more sensitive to heat than the cold stress. • The mRNA expressions levels of CaHSP70, CaHSC70 and CaHSPA9 play important roles in the response to the pathogen (Edwardsiella tarda) infection. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA) haplogroups affect the assembly and stability of the mitochondrial respiratory chain, which is potentially related to susceptibility to ischemic stroke (IS). However, the role of mtDNA in IS has not been comprehensively studied. The purpose of this study was to explore whether mtDNA polymorphisms and haplogroups are involved in the etiology of IS in the Chinese Han population. We recruited 200 patients with IS and 200 matched controls and genotyped them for 18 mtDNA single nucleotide polymorphisms defining the major Eastern Asian haplogroups by SNaPshot minisequencing. We also sequenced the hypervariable segment I (HVS-I), position 16051-16400. The prevalence of haplogroup D4b was significantly lower in IS patients than in healthy controls (0 and 8 %, respectively, corrected P = 2 × 10, odds ratio = 0.028, 95 % confidence interval = 0.002-0.468).The positive association between haplogroup D4b and IS may be related to the protective effect of haplogroup D4b against oxidative damage, which decreases the risk of IS. Our study provides the first evidence that haplogroup D4b is a potential genetic protective factor for IS in the Chinese Han population. [ABSTRACT FROM AUTHOR]

Background Lung cancer is one of the higher incidences of malignant tumors around the world. At present, tumor markers CEA, CA19-9, and CA-125 in serum are used for the diagnosis of lung cancer, however, fewer studies have shown tumor markers for early diagnosis. Therefore, using quantitative mass spectrometry, differential mitochondrial proteome analysis was performed, comparing human lung adenocarcinoma and normal bronchial epithelium cells. Methods A human lung adenocarcinoma cell line A549 and a normal human bronchial epithelial cell line 16HBE were cultured in vitro. The cell mitochondria of the two cell lines were extracted and purified by differential centrifugation and percoll density gradient centrifugation. The integrity and purity of mitochondria were validated by electron microscopy and Western-blot. The proteins/peptides from lung cancer cells and normal cells were marked by the same amount of relative and absolute quantification of ectopic tags ( iTRAQ). The mixed samples were analyzed and identified by two-dimensional liquid chromatography - tandem mass spectrometry ( 2D- LC-MS/ MS). The proteome was analyzed with different bioinformatic tools. Results One hundred and sixty-one mitochondrial proteins were identified. One hundred and fifty-three mitochondrial proteins, which were expressed differently between 16HBE cells and A549 cells, were identified. Sixty-seven proteins were high expression, while 86 proteins were lower expression. Expression of three proteins: ornithine aminotransferase ( OAT), heat shock protein beta90 ( HSP90), and vimentin ( VIM), was increased more than twice. Our results, in combination with the literature review, suggest that HSP90 and Vimentin may be the new tumor markers of lung cancer. [ABSTRACT FROM AUTHOR]

Porcine astrovirus (PAstV) has been identified as an important diarrheic pathogen with a broad global distribution. The PAstV is a potential pathogen to human beings and plays a role in public health. Until now, the divergence characteristics and pathogenesis of the PAstV are still not well known. In this study, the PAstV-4 strain PAstV/CH/2022/CM1 was isolated from the diarrheal feces of a piglet in Shanghai, which was identified to be a recombination of PAstV4/JPN (LC201612) and PAstV4/CHN (JX060808). A time tree based on the ORF2 protein of the astrovirus demonstrated that type 2-5 PAstV (PAstV-2 to 5) diverged from type 1 PAstV (PAstV-1) at a point from 1992 to 2000. To better understand the molecular basis of the virus, we sought to explore the host cell response to the PAstV/CH/2022/CM1 infection using proteomics. The results demonstrate that viral infection elicits global protein changes, and that the mitochondria seems to be a primary and an important target in viral infection. Importantly, there was crosstalk between autophagy and apoptosis, in which ATG7 might be the key mediator. In addition, the NOD-like receptor X1 (NLRX1) in the mitochondria was activated and participated in several important antiviral signaling pathways after the PAstV/CH/2022/CM1 infection, which was closely related to mitophagy. The NLRX1 may be a crucial protein for antagonizing a viral infection through autophagy, but this has yet to be validated. In conclusion, the data in this study provides more information for understanding the virus genomic characterization and the potential antiviral targets in a PAstV infection.

Mitochondrial trifunctional protein (MTP) deficiency (MTPD; MIM 609015) is a metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive disorder caused by mutations in the HADHA gene, encoding the α-subunit of a trifunctional protease, or in the HADHB gene, encoding the β-subunit of a trifunctional protease. To the best of our knowledge, only two cases of families with MTPD due to HADHB gene mutations have been reported in China, and the HADHA gene mutation has not been reported in a Chinese family with MTPD. The present study reported the clinical characteristics and compound heterozygous HADHA gene mutations of two patients with MTPD in the Chinese population. The medical history, routine examination data, blood acyl-carnitine analysis results, results of pathological examination after autopsy and family pedigree map were collected for patients with MTPD. The HADHA gene was analyzed by Sanger sequencing or high-throughput sequencing, the pathogenicity of the newly discovered variant was interpreted by bioinformatics analysis, and the function of the mutated protein was modeled and analyzed according to 3D structure. The two patients with MTPD experienced metabolic crises and died following an infectious disease. Lactate dehydrogenase, creatine kinase (CK), CK-MB and liver enzyme abnormalities were observed in routine examinations. Tandem mass spectrometry revealed that long-chain acyl-carnitine was markedly elevated in blood samples from the patients with MTPD. The autopsy results for one child revealed fat accumulation in the liver and heart. Next-generation sequencing detected compound heterozygous c.703C>T (p.R235W) and c.2107G>A (p.G703R) mutations in the HADHA gene. The mother did not have acute fatty liver during pregnancy with the two patients. Using amniotic fluid prenatal diagnostic testing, the unborn child was confirmed to carry only c.2107G>A (p.G703R). Molecular mechanistic analysis indicated that the two variants affected the conformation of the α-subunit of the MTP enzyme complex, and consequently affected the stability and function of the enzyme complex. The present study comprehensively analyzed the cases, including exome sequencing and protein structure analysis and, to the best of our knowledge, describes the first observation of compound heterozygous mutations in the HADHA gene underlying this disorder in China. The clinical phenotypes of the two heterozygous variants of the HADHA gene are non-lethal. The present study may improve understanding of the HADHA gene mutation spectrum and clinical phenotype in the Chinese population. [ABSTRACT FROM AUTHOR]

Thyroid dysgenesis (TD) accounts for 80% cases of congenital hypothyroidism, which is the most common neonatal disorder. Until now, the gene mutations have been reported associated with TD can only account for 5% cases, suggesting the genetic heterogeneity of the pathology. Nicotinamide nucleotide transhydrogenase (NNT) plays a crucial role in regulating redox homeostasis, patients carrying NNT mutations have been described with a clinical phenotype of hypothyroidism. As TD risk is increased in the context of several syndromes and redox homeostasis is vital for thyroid development and function, NNT might be a candidate gene involved in syndromic TD. Therefore, we performed target sequencing (TS) in 289 TD patients for causative mutations in NNT and conducted functional analysis of the gene mutations. TS and Sanger sequence were used to screen the novel mutations. For functional analysis, we performed western blot, measurement of NADPH/NADP total and H 2 O 2 generation, cell proliferation, and wounding healing assay. As a result, three presumably pathogenic mutations (c.811G > A, p.Ala271Ser; c.2078G > A, p.Arg693His; and c.2581G > A, p.Val861Met) in NNT had been identified. Our results showed the damaging effect of NNT mutations on stability and catalytic activity of proteins and redox balance of cells. In conclusion, our findings provided novel insights into the role of the NNT isotype in thyroid physiopathology and broaden the spectrum of pathogenic genes associated with TD. However, the pathogenic mechanism of NNT in TD is still need to be investigated in further study., (© 2021 Wiley Periodicals LLC.)

Pathological variants in the nuclear malonyl-CoA-acyl carrier protein transacylase (MCAT) gene, which encodes a mitochondrial protein involved in fatty-acid biogenesis, have been reported in two siblings from China affected by insidious optic nerve degeneration in childhood, leading to blindness in the first decade of life. After analysing 51 families with negative molecular diagnostic tests, from a cohort of 200 families with hereditary optic neuropathy (HON), we identified two novel MCAT mutations in a female patient who presented with acute, sudden, bilateral, yet asymmetric, central visual loss at the age of 20. This presentation is consistent with a Leber hereditary optic neuropathy (LHON)-like phenotype, whose existence and association with NDUFS2 and DNAJC30 has only recently been described. Our findings reveal a wider phenotypic presentation of MCAT mutations, and a greater genetic heterogeneity of nuclear LHON-like phenotypes. Although MCAT pathological variants are very uncommon, this gene should be investigated in HON patients, irrespective of disease presentation. [ABSTRACT FROM AUTHOR]

Objective: To investigate the diagnostic value of mitochondrial associated protein fumarylacetoacetate domain containing protein 1 (FAHD1) and growth differentiation factor-15 (GDF-15) in sepsis., Methods: Based on the database of the whole process of sepsis early warning, diagnosis and treatment management, which was established on the study of sepsis early warning and standardized diagnosis and treatment system, adult patients with suspected infection admitted to the department of critical care medicine of Zhejiang Hospital, Second Affiliated Hospital of Zhejiang University, the First Affiliated Hospital of Sun Yat-Sen University, West China Hospital of Sichuan University, Ningbo First Hospital from May 2014 to October 2015 were enrolled. The basic vital signs, and the main blood routine results, liver and kidney function, blood gas, acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) score at the time of diagnosis of patients with or without sepsis were analyzed. The preserved serum samples were taken, the levels of procalcitonin (PCT), C-reactive protein (CRP) were detected by electrochemiluminescence method, immunoturbidimetry respectively, and FAHD1 and GDF-15 were detected by enzyme linked immunosorbent assay (ELISA). Univariate and multivariate Logistic regression were used to analyze the risk factors for sepsis diagnose. The indexes' diagnostic efficacy in sepsis were analyzed by receiver operating characteristics curve (ROC curve)., Results: A total of 132 patients were enrolled, including 76 cases of sepsis and 56 cases of non-sepsis. Compared with the non-sepsis group, the heart rate in the sepsis group was increased (bpm: 116.4±17.8 vs. 97.4±19.1), while the mean arterial pressure (MAP), platelet count (PLT), arterial partial pressure of oxygen (PaO 2 ) were significantly decreased [MAP (mmHg, 1 mmHg = 0.133 kPa): 65.8±9.7 vs. 74.7±10.3, PLT (×10 9 /L): 120 (69, 204) vs. 163 (117, 239), PaO 2 (mmHg): 83.0 (66.6, 108.0) vs. 108.0 (84.4, 130.0), all P < 0.05], direct bilirubin (DBil), serum creatinine (SCr), lactic acid (Lac), APACHE II score and SOFA score were significantly increased [DBil (μmol/L): 13.00 (5.55, 55.31) vs. 6.20 (2.20, 21.90), SCr (μmol/L): 118.00 (70.00, 191.73) vs. 77.20 (59.65, 110.86), Lac (mmol/L): 2.90 (1.50, 4.10) vs. 1.90 (1.20, 2.80), APACHE II score: 20.0 (16.0, 25.0) vs. 16.0 (10.0, 21.0), SOFA score: 12.0 (8.0, 16.0) vs. 8.0 (5.0, 13.0), all P < 0.05]. In addition, the serum levels of FAHD1, GDF-15, PCT and CRP in sepsis group were significantly higher than those in non-sepsis group [FAHD1 (μg/L): 3.96 (2.25, 5.92) vs. 2.47 (1.03, 3.54), GDF-15 (μg/L): 8.46 (4.37, 19.68) vs. 4.32 (1.74, 10.39), PCT (μg/L): 3.79 (1.37, 11.32) vs. 0.42 (0.12, 2.14), CRP (mg/L): 154.43 (61.33, 283.20) vs. 65.95 (28.15, 144.69), all P < 0.01]. Multivariate Logistic regression showed that serum FAHD1 [odds ratio (OR) = 1.135, 95% confidence interval (95%CI) was 1.045-1.234], GDF-15 (OR = 1.090, 95%CI was 1.029-1.155) and CRP (OR = 1.007, 95%CI was 1.002-1.011) were risk factors for sepsis (all P < 0.05). ROC curve analysis of sepsis showed that the areas under ROC curve (AUC) of serum mitochondrial associated proteins FAHD1 and GDF-15 were 0.727 (95%CI was 0.641-0.802) and 0.677 (95%CI was 0.588-0.757), respectively; and the AUC of classical infection indexes PCT and CRP were 0.767 (95%CI was 0.683-0.837) and 0.680 (95%CI was 0.59-0.760), respectively. There was no significant difference between the AUC of mitochondrial associated proteins and classical infection indexes. The combination of FAHD1, GDF-15, PCT and CRP had the largest AUC, which was 0.809 (95%CI was 0.730-0.874), and the sensitivity was 75.00%, and the specificity was 80.00%., Conclusions: Mitochondrial associated protein FAHD1 and GDF-15 are associated with sepsis, and the diagnostic efficiency is improved when combined with PCT and CRP, which might provide experimental basis for screening diagnostic markers of sepsis.

Introduction: G elongation factor mitochondrial 1 (GFM1) encodes one of the mitochondrial translation elongation factors. GFM1 variants were reported to be associated with neurological diseases and liver diseases in a few cases. Here, we present a novel composition of two heterozygous mutations of GFM1 in a boy with epilepsy, mental retardation, and other unusual phenotypes., Methods: The patient was found to be blind and experienced recurrent convulsive seizures such as nodding and hugging at the age of 3 months. After antiepileptic treatment with topiramate, he had no obvious seizures but still had mental retardation. The patient vomited frequently at 16 months old, sometimes accompanied by epileptic seizures. Hematuria metabolic screening, mutation screening of mitochondrial gene, and mitochondrial nuclear gene were negative. Then, he was analyzed by whole-exome sequencing (WES)., Results: Whole-exome sequencing revealed a novel composition of two heterozygous mutations in GFM1, the maternal c.679G > A (has not been reported) and the paternal c.1765-1&#95;1765-2del (previously reported). At present, there is no specific and effective treatment for the disease, and the prognosis is very poor., Conclusion: The discovery of new phenotypes and new genotypes will further enrich the diagnosis information of the disease and provide more experiences for clinicians to quickly diagnose the disease and judge the prognosis., (© 2020 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

Hesperiidae is one of the largest families of butterflies. Our knowledge of the higher systematics on hesperiids from China is still very limited. We infer the phylogenetic relationships of the subfamilies of Chinese skippers based on three mitochondrial genes (cytochrome b (Cytb), the NADH dehydrogenase subunit 1 (ND1) and cytochrome oxidase I (COI)). In this study, 30 species in 23 genera were included in the Bayesian and maximum likelihood analyses. The subfamily Coeliadinae, Eudaminae, Pyrginae and Heteropterinae were recovered as a monophyletic clade with strong support. The subfamily Hesperiinae formed a clade, but support for monophyly was weak. Our results imply that the five subfamilies of Chinese Hesperiidae should be divided into: Coeliadinae, Eudaminae, Pyrginae, Heteropterinae and Hesperiinae. The relationships of the five subfamilies should be as follows: Coeliadinae + (Eudaminae + (Pyrginae + (Heteropterinae + Hesperiinae))). [ABSTRACT FROM AUTHOR]

Purpose: Autosomal dominant progressive external ophthalmoplegia (adPEO) is a genetically heterogeneous, adult-onset disease. Thus far, disease loci have been identified on four different nuclear genes. The purpose of this study is to identify the gene responsible for causing adPEO in a Chinese family., Methods: Clinical data and genomic DNA of a Chinese adPEO family were collected following informed consent. Gene scan by two-point linkage analysis was performed for four genes, and mutation screening was conducted in the Twinkle (PEO1) gene by direct sequencing., Results: A maximum two-point LOD score of 2.8 at theta=0.00 was obtained with marker D10S192 in close proximity to PEO1. A novel missense mutation (c.1423G>A, p.475A>T) was identified., Conclusions: This study widens the mutation spectrum of PEO1 and is the first to report the PEO1 mutation in the Chinese population.

In this report, we studied on a homoplasmic T12338C change in mitochondrial DNA (mtDNA), which substituted methionine in the translational initiation codon of the NADH dehydrogenase subunit 5 gene ( ND5) with threonine. This nucleotide change was originally identified in two mtDNAs belonging to haplogroup F2 by our previous complete sequencing of 48 mtDNAs. Since then, a total of 76 F2 mtDNAs have been identified by the variations occurring in the hypervariable segments and coding regions among more than 3,000 individuals across China. As the T12338C change was detected in 32 samples representing various sub-clades of the F2 haplogroup while not in 14 non-F2 controls, we believe that the T12338C change is specific to the F2 haplogroup. As F2 and its sub-clades were widely distributed in normal individuals of various Chinese populations, we conclude that T12338C is not pathogenic. In addition, based on the average distribution frequency, haplotype diversity and nucleotide diversity of haplogroup F2 in the populations across China, the T12338C nucleotide substitution seems to have been occurred in north China about 42,000 years ago. Our results provided a good paradigm for distinguishing a polymorphic change from a pathogenic mutation based on mtDNA phylogeny.