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Background Alzheimer's disease (AD) is the most common neurodegenerative disorder in humans and presents a major health problem throughout the world. The etiology of AD is complex, and many factors are implicated, including mitochondria. Mitochondrial alteration has been proposed as a possible cause of AD. Therefore, several studies have focused on finding an association between inherited mitochondrial DNA variants and AD onset. Methods In this study, we looked, for the first time, for a potential association between mitochondrial haplogroups or polymorphisms and AD in the Tunisian population. We also evaluated the distribution of the major genetic risk factor for AD, the apolipoprotein E epsilon 4 (APOE e4), in this population. In total, 159 single-nucleotide polymorphisms (SNPs) of mitochondrial DNA haplogroups were genotyped in 254 individuals (58 patients and 196 controls). An additional genotyping of APOE e4 was performed. Results No significant association between mitochondrial haplogroups and AD was found. However, two individual SNPs, A5656G (p = 0.03821, OR = 10.46) and A13759G (p = 0.03719, OR = 10.78), showed a significant association with AD. APOE 4 was confirmed as a risk factor for AD (p = 0.000014). Conclusion Our findings may confirm the absence of a relation between mitochondrial haplogroups and AD and support the possible involvement of some inherited variants in the pathogenicity of AD.

STUDY QUESTIONAre relative mitochondrial DNA (mtDNA) content and mitochondrial genome (mtGenome) variants in human cumulus cells (CCs) associated with oocyte reproductive potential and assisted reproductive technology (ART) outcomes?SUMMARY ANSWERNeither the CC mtDNA quantity nor the presence of specific mtDNA genetic variants was associated with ART outcomes, although associations with patient body mass index (BMI) were detected, and the total number of oocytes retrieved differed between major mitochondrial haplogroups.WHAT IS KNOWN ALREADYCCs fulfil a vital role in the support of oocyte developmental competence. As with other cell types, appropriate cellular function is likely to rely upon adequate energy production, which in turn depends on the quantity and genetic competence of the mitochondria. mtDNA mutations can be inherited or they can accumulate in somatic cells over time, potentially contributing to aging. Such mutations may be homoplasmic (affecting all mtDNA in a cell) or they may display varying levels of heteroplasmy (affecting a proportion of the mtDNA). Currently, little is known concerning variation in CC mitochondrial genetics and how this might influence the reproductive potential of the associated oocyte.STUDY DESIGN, SIZE, DURATIONThis was a prospective observational study involving human CCs collected with 541 oocytes from 177 IVF patients. mtDNA quantity was measured in all the samples with a validated quantitative PCR method and the entire mtGenome was sequenced in a subset of 138 samples using a high-depth massively parallel sequencing approach. Associations between relative mtDNA quantity and mtGenome variants in CCs and patient age, BMI (kg/m2), infertility diagnosis and ART outcomes were investigated.PARTICIPANTS/MATERIALS, SETTING, METHODSMassively parallel sequencing permitted not only the accurate detection of mutations but also the precise quantification of levels of mutations in cases of heteroplasmy. Sequence variants in the mtDNA were evaluated using Mitomaster and HmtVar to predict their potential impact.MAIN RESULTS AND THE ROLE OF CHANCEThe relative mtDNA CC content was significantly associated with BMI. No significant associations were observed between CC mtDNA quantity and patient age, female infertility diagnosis or any ART outcome variable. mtGenome sequencing revealed 4181 genetic variants with respect to a reference genome. The COXI locus contained the least number of coding sequence variants, whereas ATPase8 had the most. The number of variants predicted to affect the ATP production differed significantly between mitochondrial macrohaplogroups. The total number of retrieved oocytes was different between the H-V and J-T as well as the U-K and J-T macrohaplogroups. There was a non-significant increase in mtDNA levels in CCs with heteroplasmic mitochondrial mutations.LARGE SCALE DATAN/A.LIMITATIONS, REASONS FOR CAUTIONAlthough a large number of samples were analysed in this study, it was not possible to analyse all the CCs from every patient. Also, the results obtained with respect to specific clinical outcomes and macrohaplogroups should be interpreted with caution due to the smaller sample sizes when subdividing the dataset.WIDER IMPLICATIONS OF THE FINDINGSThese findings suggest that the analysis of mtDNA in CCs is unlikely to provide an advantage in terms of improved embryo selection during assisted reproduction cycles. Nonetheless, our data raise interesting biological questions, particularly regarding the interplay of metabolism and BMI and the association of mtDNA haplogroup with oocyte yield in ovarian stimulation cycles.STUDY FUNDING/COMPETING INTEREST(S)This study was funded by National Institutes of Health grant 5R01HD092550-02. D.J.N. and C.R. co-hold patent US20150346100A1 and D.J.N. holds US20170039415A1, both for metabolic imaging methods. D.W. receives support from the NIHR Oxford Biomedical Research Centre. The remaining authors have no conflicts of interest to declare.

Risk factors for meningioma include female gender, African American race, high body mass index (BMI), and exposure to ionizing radiation. Although genome-wide association studies (GWAS) have identified two nuclear genome risk loci for meningioma (rs12770228 and rs2686876), the relation between mitochondrial DNA (mtDNA) sequence variants and meningioma is unknown. We examined the association of 42 common germline mtDNA variants (minor allele frequency ≥ 5%), haplogroups, and genes with meningioma in 1080 controls and 478 meningioma cases from a case–control study conducted at medical centers in the southeastern United States. Associations were examined separately for meningioma overall and by WHO grade (n = 409 grade I and n = 69 grade II/III). Overall, meningioma was significantly associated with being female (OR 2.85; 95% CI 2.21–3.69), self-reported African American race (OR 2.38, 95% CI 1.41–3.99), and being overweight (OR 1.48; 95% CI 1.11–1.97) or obese (OR 1.70; 95% CI 1.25–2.31). The variant m.16362T > C (rs62581341) in the mitochondrial control region was positively associated with grade II/III meningiomas (OR 2.33; 95% CI 1.14–4.77), but not grade I tumors (OR 0.99; 95% CI 0.64–1.53). Haplogroup L, a marker for African ancestry, was associated with meningioma overall (OR 2.92; 95% CI 1.01–8.44). However, after stratifying by self-reported race, this association was only apparent among the few self-reported Caucasians with this haplogroup (OR 6.35; 95% CI 1.56–25.9). No other mtDNA variant, haplogroup, or gene was associated with meningioma. Common mtDNA variants and major mtDNA haplogroups do not appear to have associations with the odds of developing meningioma.

Reports have questioned the dogma of exclusive maternal transmission of human mitochondrial DNA (mtDNA), including the recent report of an admixture of two mtDNA haplogroups in individuals from three multigeneration families. This was interpreted as being consistent with biparental transmission of mtDNA in an autosomal dominant–like mode. The authenticity and frequency of these findings are debated. We retrospectively analyzed individuals with two mtDNA haplogroups from 2017 to 2019 and selected four families for further study. We identified this phenomenon in 104/27,388 (approximately 1/263) unrelated individuals. Further study revealed (1) a male with two mitochondrial haplogroups transmits only one haplogroup to some of his offspring, consistent with nuclear transmission; (2) the heteroplasmy level of paternally transmitted variants is highest in blood, lower in buccal, and absent in muscle or urine of the same individual, indicating it is inversely correlated with mtDNA content; and (3) paternally transmitted apparent large-scale mtDNA deletions/duplications are not associated with a disease phenotype. These findings strongly suggest that the observed mitochondrial haplogroup of paternal origin resulted from coamplification of rare, concatenated nuclear mtDNA segments with genuine mtDNA during testing. Evaluation of additional specimen types can help clarify the clinical significance of the observed results.

The life on earth is driven by energy, supplied by the tiny organelles of the cell called mitochondria and they are usually stated as the powerhouses of the cell. In population genetics, Mitochondrial DNA (mtDNA) is used extensively to categorize individuals or populations. The mutation sites observed in human mtDNA by comparing with the reference sequence (rCRS) are termed into definite human mtDNA haplogroups. Previous studies showed that mtDNA specific haplogroups and polymorphisms were established to be linked with various human diseases, including cancer in numerous populations. Furthermore, it is also known that several mitochondrial DNA polymorphisms are implicated in enhanced production of Reactive Oxygen Species (ROS) which are known to be an increased risk cause for several cancers, including colorectal cancer in Indian patients. Hence in our study, we made high resolution examination on mtDNA hypervariable region to trace the association of specific mtDNA haplogroup with colorectal cancer in south Indian populations. We report that mtDNA Haplogroup M was observed in 60% of the colorectal cancer patients and around 55% in the studied control samples. Haplogroup M is the most frequent mtDNA cluster found among south Indian populations. We further sub-lineated macro haplogroup M and found sub haplogroups (M8, M7, M6, M5, M3 and M2) in varied frequencies. In particular, we found significant association of haplogroup M5 with colorectal cancer patients (p = 0.026). Haplogroup M5 was observed in 12% of colorectal cancer patients in south Indian patients and in 3.3% of the control populations. These results suggest that individuals with haplogroup M5 may have significant risk to develop colorectal cancer.

The Caribbean Acropora corals, A. palmata and A. cervicornis form a hybrid with two broad morphotypes, bushy and palmate. These morphotypes were previously hypothesized to be linked to the hybrid’s maternal species. Here, we expand on this hypothesis by adding samples from across the range and by increasing genetic resolution. We reconstructed complete mitochondrial genomes as a proxy for maternal species. This yielded novel A. palmata haplogroups, only one of which was shared by all three taxa. Experts then evaluated photographs to classify corals to a taxon based on colony morphology. Expert classification revealed less accuracy and confidence in hybrid, and surprisingly A. palmata identification compared to A. cervicornis. No association between the bushy morph and mitochondrial haplogroups was found when mapping hybrid morphotypes to the mitogenome phylogeny. Therefore, mitochondrial haplogroup membership is not predictive of Caribbean acroporid hybrid morphology across the range. Additional work is needed to uncover determinants of colony morphology.

Mutations in mitochondrial DNA (mtDNA) are found to be associated with type 2 diabetes mellitus (T2DM). However, the molecular pathogenesis of these mutations in T2DM is still poorly understood. In this study, we report here the molecular features of two Han Chinese families with maternally transmitted T2DM. The matrilineal relatives are undergoing clinical, biochemical, genetic evaluations, and molecular analysis. Furthermore, the entire mitochondrial genomes of these matrilineal relatives are screened by PCR-Sanger sequencing. The age at onset of T2DM of these participants varies from 28 to 71 years, with an average of 43 years. Molecular analysis of mitochondrial genomes identifies the existence of ND1 T3394C mutation in both families, together with sets of variants belonging to mitochondrial haplogroup Y2 and M9a. The m.T3394C mutation is localized at very conserved tyrosine at position 30 of ND1, may result the failure in ND1 mRNA metabolism, and lead to mitochondrial dysfunction. Moreover, sequence analysis of matrilineal relatives in Family 1 identifies the m.A14693G mutation which occurs in the TΨC-loop of tRNAGlu (position 54), and is critical to the structural formation and stabilization of this tRNA. Thus, m.A14693G mutation may cause the impairment in tRNA metabolism, thereby worsens the mitochondrial dysfunction caused by ND1 T3394C mutation. However, no functional mtDNA variants are identified in Family 2 which suggest that mitochondrial haplogroup may not play an important role in diabetes expression. Our study indicates that mitochondrial ND1 T3394C mutation is involved in the pathogenesis of maternally inherited T2DM in these families.

The study aims at determining Y-DNA and mtDNA haplogroups of two early medieval Slavic burials at Bolshevo-1 burial ground (near Zagoryansky settlement) on the Klyazma River to consider their possible analogs in other samples of medieval Slavic DNA and to give a historical, archaeological and anthropological interpretation of the result. The comparison of the skulls from Bolshevo-1 with the craniological Slavic series has shown their proximity to the Serbian and West Slavic series. The belonging of Individuals 5666 and 5672 to Y-DNA haplogroups E1b1b and J2a1 suggests the Danube component in the ethnogenesis of this group of the Krivichi tribe, which came from the Upper Volga and the Novgorod-Smolensk border. The mitochondrial haplogroup of Individual 5666 H1e1b allows considering the Baltic branch of the ethnogenesis of this group.

Obesity, a major risk factor for metabolic disorders, is highly prevalent in Qatari population. Maternal transmission of obesity traits can be significant; for example, X haplogroup is known to be associated with lower BMI and body fat mass in Northern Europeans and T haplogroup which is a sister haplogroup of J is known to be associated with obesity in Caucasian subjects from Austria and Southern Italy. We aimed to delineate the mitochondrial haplogroups and variants associated with obesity in Qatari population. Mitochondrial genomes of 864 Qatari individuals were extracted from whole exome sequencing data with an average coverage of 77X. We distributed the participants into 2 sub-cohorts: obese (BMI ≥ 30) and non-obese (BMI P = 0.0038; the Bonferroni adjusted P value threshold is 0.0041), whereas the individuals with haplogroup X were at low risk of obesity (OR 0.387; 95% CI 0.175–0.857; P = 0.019). Further, a set of 38 mitochondrial variants were found to be associated (at P ≤ 0.05) with obesity in models adjusted for age, sex and haplogroup.

We present the results of a paleogenetic analysis of bone samples representing seven adult individuals from Bertek-33—an Afanasyevo cemetery on the Ukok plateau, in the Altai Republic, Russia. The fi ndings are interpreted with reference to archaeological and anthropological data. Four systems of genetic markers were analyzed: mitochondrial DNA, polymorphic fragment of the amelogenin gene, autosomal STR-loci, and Y-chromosomal STR-loci. Genetic results indicate the dominance of Western Eurasian mtDNA haplogroups (T, J, U5a, K, H) and the homogeneity of the male gene-pool represented by variants of the Y-chromosomal haplogroup R1b. Data on mtDNA, Y-chromosome, and individual autosomal markers attest to the Western Eurasian affi nities of this group. The sample falls within the mtDNA and Y-chromosomal diversity of the Afanasyevo population of southern Siberia. Possible kinship between the individuals buried at Bertek-33 is discussed. Also, we address theoretical issues such as the accuracy of comparisons and the interpretation of genetic data with regard to cultural features.

Aim The objective of this study was to explore the association between mitochondrial DNA (mtDNA) haplogroups and physical performances in Han older adults. Methods This study was an 8-year follow-up prospective cohort study. A total of 104 Han older adults completed the measurements of the 6-min walk test, grip strength and mitochondrial DNA sequencing. The mtDNA haplogroups were classified by using HaploGrep2 software. We used the mixed model to analyze the longitudinal effect of mtDNA haplogroups on physical performance tests among three waves of data. Results The mean age at wave 3 among men and women were 78.3 and 77.2 years, respectively. The overall proportions of mtDNA haplogroups in this study population was 26.9% F, 21.2% M, 15.4% R, 14.4% D, 8.7% B and others. After adjusted for age, sex, ethnicity, body mass index and exercise, the interaction of mtDNA haplogroup M and waves significantly affected the 6-min walk distance. Notably, the adjusted mean of the 6-min walk distance among the group of mtDNA haplogroup M was significantly lower than other haplogroups at wave 3. The adjusted mean of grip strength among the group of mtDNA haplogroup R was significantly higher than other haplogroups at wave 3. Conclusions This finding suggests that mtDNA haplogroups might have effects on the 6-min walk test and grip strength in Han older adults, although studies of the physical performance of older adults with larger sample sizes are necessary to further substantiate these findings. Geriatr Gerontol Int 2021; 21: 166-171.

Mitochondria play an important role in cell survival, function and lineage differentiation. Changes in mitochondrial DNA (mtDNA) may control mitochondrial functions and thus may impart an alternative cellular state thereby leading to a disease condition in the body. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease wherein immune cells become self-reactive causing joint inflammation, swelling and pain in patients. The changes in mtDNA may alter cellular functions thereby directing the immune cells towards an inflammatory phenotype in RA. Therefore, it becomes pertinent to identify changes in mtDNA sequence in immune cells of RA patients to understand the pathogenesis and progression of RA.mtDNA from peripheral blood mono-nuclear cells (PBMCs) of 23 RA patients and 17 healthy controls (HCs) were sequenced using next-generation sequencing (NGS). Further, single nucleotide polymorphisms (SNPs) and other variable changes in mtDNA hypervariable and coding regions, amino acid changes with a putative impact on disease, levels of heteroplasmy, copy number variations and haplogroup analysis in RA patients and HCs were analysed and compared to identify any association of mtDNA changes and RA disease.A total of 382 single nucleotide mtDNA variants were observed, 91 (23.82%) were present in hypervariable region and 291 (76.18%) in coding region of patients and HC. The variant 513 GCA ACA, with G present in HVR-III, known to control the mitochondrial translation function, was significantly present in RA patients. The CYTB gene had larger number of SNPs in HC samples while RNR2 was more variable in RA patients. A non-synonymous heteroplasmy in ND1 gene was found at a single nucleotide position 3533 in an increased number of RA patients as compared to the controls. A significant increase in mtDNA duplication and a higher frequency of the haplogroup U was also characteristic of RA. Also, the presence of SNPs in mitochondrial tRNA genes at two positions 12308 A G and 15924 A G were found to be pathogenic.We herein observed an altered mtDNA sequence in immune cells of RA patients and thus a possible role of mitochondrial genome in the development of RA. The observed nucleotide changes in mtDNA control region, RNR2 gene, increased heteroplasmy and mtDNA duplication in RA patients may alter sites for transcription factor binding thereby influencing mtDNA gene expression, as well as copy numbers thereby affecting the mitochondrial proteins and their functions. These changes in mtDNA could be one of the probable reasons among many leading to the progression of RA.

Takabuti, was a female who lived in ancient Egypt during the 25th Dynasty, c.660 BCE. Her mummified remains were brought to Belfast, Northern Ireland, in 1834 and are currently displayed in the Ulster Museum. To gain insight into Takabuti’s ancestry, we used deep sampling of vertebral bone, under X-ray control, to obtain non-contaminated bone tissue from which we extracted ancient DNA (aDNA) using established protocols. We targeted the maternally inherited mitochondrial DNA (mtDNA), known to be highly informative for human ancestry, and identified 38 single nucleotide variants using next generation sequencing. The specific combination of these SNVs suggests that Takabuti belonged to mitochondrial haplogroup H4a1. Neither H4 nor H4a1 have been reported in ancient Egyptian samples, prior to this study. The modern distribution of H4a1 is rare and sporadic and has been identified in areas including the Canary Islands, southern Iberia and the Lebanon. H4a1 has also been reported in ancient samples from Bell Beaker and Unetice contexts in Germany, as well as Bronze Age Bulgaria. We believe that this is an important finding because first, it adds to the depth of knowledge about the distribution of the H4a1 haplogroup in existing mtDNA, thus creating a baseline for future occurrences of this haplogroup in ancient Egyptian remains. Second, it is of great importance for archaeological sciences, since a predominantly European haplogroup has been identified in an Egyptian individual in Southern Egypt, prior to the Roman and Greek influx (332BCE).

In forensic analyses, determining the level of consensus among examiners for hair comparison conclusions and ancestry identifications is important for assessing the scientific validity of microscopical hair examinations. Here, we present data from an interlaboratory study on the accuracy of microscopical hair comparisons among a subset of experienced hair examiners currently analyzing hair in forensic laboratories across the United States. We examined how well microscopical analysis of hair can reliably be used to differentiate hair samples, many of which were macroscopically similar. Using cut hair samples, many sharing similar macroscopic and microscopic features, collected from individuals who share the same mitochondrial haplogroup as an indication of genetic relatedness, we tested multiple aspects that could impact hair comparisons. This research tested the extent to which morphological features related to ancestry and hair length influence conclusions. Microscopical hair examinations yielded accurate assessments of inclusion/exclusion relative to the reference samples among 85% of the pairwise comparisons. We found shorter hairs had reduced levels of accuracy and hairs from populations examiners were not familiar with may have impacted their ability to resolve features. The reliability of ancestry determinations is not yet clear, but we found indications that the existing categories are only somewhat related to current ethnic and genetic variation. Our results provide support for the continued utility of microscopical comparison of hairs within forensic laboratories and to advocate for a combined analytical approach using both microscopical analysis and mtDNA data on all forensic analyses of hair.

This is a review of studies on the genetic polymorphism of modern and ancient populations of the north of Asia and America, with the aim of reconstructing the history of migrations of ancient marine hunters in the Okhotsk Sea region. The data on mitochondrial DNA polymorphism and the “Arctic” mutation distribution – the rs80356779-A variant of the CPT1A gene – were analyzed. It is known that the “Arctic” variant of the CPT1A gene is widely distributed in modern populations of the Eskimos, Chukchis, Koryaks, and other peoples of the Okhotsk Sea region, whose economic structure is associated with marine hunting. According to paleogenomic data, the earliest cases of the “Arctic” variant of the CPT1A gene were found in the Greenland and Canadian Paleoeskimos (4 thousand years ago), among representatives of the Tokarev culture of the Northern Priokhotye (3 thousand years ago), and among the bearers of the culture of the late Jomon of Hokkaido (3.5–3.8 thousand years ago). The results of the analysis revealed several migration events associated with the spread of marine hunters in the Okhotsk Sea region. The latest migration, which left traces on bearers of the Epi-Jomon culture (2.0–2.5 thousand years ago), introduced the mitochondrial haplogroup G1b and the “Arctic” variant of the CPT1A gene from the north of Priokhotye to Hokkaido and neighboring territories of the Amur Region. Traces of earlier migration, which also brought the “Arctic” mutation, were recorded in the Hokkaido population of the late Jomon period (3.5–3.8 thousand years ago). A phylogenetic analysis of mitochondrial genomes belonging to the rare haplogroup C1a, found in populations of the Far East and Japan, but phylogenetically related to the C1-haplogroups of the Amerindians, was carried out. The results of the analysis showed that the divergence of mitochondrial lineages within the C1a haplogroup occurred in the range from 7.9 to 6.6 thousand years ago, and the age of the Japanese branch of the C1a haplogroup is approximately 5.2 thousand years. It is not yet known whether this migration is associated with the spread of the “Arctic” variant of the CPT1A gene or the presence of C1a haplotypes in the population of the Japanese islands marks another, earlier, episode of the migration history linking the populations of Northwest Pacific and North America.

Mitochondria are the only organelles that contain their own genetic material (mtDNA). Mitochondria are involved in several key physiological functions, including ATP production, Ca2+ homeostasis, and metabolism of neurotransmitters. Since these organelles perform crucial processes to maintain neuronal homeostasis, mitochondrial dysfunctions can lead to various neurodegenerative diseases. Several mitochondrial proteins involved in ATP production are encoded by mtDNA. Thus, any mtDNA alteration can ultimately lead to mitochondrial dysfunction and cell death. Accumulation of mutations, deletions, and rearrangements in mtDNA has been observed in animal models and patients suffering from Parkinson's disease (PD). Also, specific inherited variations associated with mtDNA genetic groups (known as mtDNA haplogroups) are associated with lower or higher risk of developing PD. Consequently, mtDNA alterations should now be considered important hallmarks of this neurodegenerative disease. This review provides an update about the role of mtDNA alterations in the physiopathology of PD.

Objective. We investigated Asian mitochondrial DNA (mtDNA) haplogroups associated with knee osteoarthritis (OA) progression in a prospective community-based cohort comprised of Koreans. Methods. Epidemiologic data and Kellgren-Lawrence (K/L) scores of knee radiographs were obtained from the second (2005∼2006) and sixth (2013∼2014) follow-up, and patient DNA was analyzed. The mtDNA haplogroup frequencies (M, G, D, D4, D5, M7, M8, M9, M10, N, A, N9, R, F, and B) were compared between the progression (K/L score change on either knee ≥2 or arthroplasty) and non-progression (K/L score change on both knee ≤1) groups at the sixth follow-up. Multiple logistic regression was performed to determine relative risk (RRs) of mtDNA haplogroups for OA. Results. In total, 1,115 participants were included, 405 of whom had early OA (higher K/L score on both knees of 1 or 2). Among them, 143 and 166 patients were classified in non-progression and progression groups, respectively, at the sixth follow-up. The most frequent haplogroups, B and D4, in Koreans also showed a high frequency in our study. There were no significantly different haplogroups between the non-progression and progression groups. However, the frequency of haplogroup D4 was likely higher in the non-progression g roup than in the progression group, although not significantly (13.3% vs. 7.2%, RR=0.51, p=0.081 in the unadjusted model and RR=0.56, p=0.149 in the adjusted model). Conclusion. No significant haplogroups are related to OA progression. Large-scaled studies are needed to reveal the association between mtDNA haplogroups and OA. (J Rheum Dis 2020;27:168-173)

Introduction Inherited mitochondrial DNA (mtDNA) variants may influence Alzheimer's disease (AD) risk. Methods We sequenced mtDNA from 146 AD and 265 cognitively normal (CN) subjects from the University of Kansas AD Center (KUADC) and assigned haplogroups. We further considered 244 AD and 242 CN AD Neuroimaging Initiative (ADNI) subjects with equivalent data. Results Without applying multiple comparisons corrections, KUADC haplogroup J AD and CN frequencies were 16.4% versus 7.6% (P = .007), and haplogroup K AD and CN frequencies were 4.8% versus 10.2% (P = .063). ADNI haplogroup J AD and CN frequencies were 10.7% versus 7.0% (P = .20), and haplogroup K frequencies were 4.9% versus 8.7% (P = .11). For the combined 390 AD and 507 CN cases haplogroup J frequencies were 12.8% versus 7.3% (P = .006), odds ratio (OR) = 1.87, and haplogroup K frequencies were 4.9% versus 9.5% (P = .010), OR = 0.49. Associations remained significant after adjusting for apolipoprotein E, age, and sex. Conclusion This exploratory analysis suggests inherited mtDNA variants influence AD risk.

The mitochondrion is an essential organelle responsible for generating cellular energy. Additionally, mitochondria are a source of inter-individual variation as they contain their own genome. Evidence has revealed that mitochondrial DNA (mtDNA) variation can confer differences in mitochondrial function and importantly, these differences may be a factor underlying the idiosyncrasies associated with unpredictable drug-induced toxicities. Thus far, preclinical and clinical data are limited but have revealed evidence in support of an association between mitochondrial haplogroup and susceptibility to specific adverse drug reactions. In particular, clinical studies have reported associations between mitochondrial haplogroup and antiretroviral therapy, chemotherapy and antibiotic-induced toxicity, although study limitations and conflicting findings mean that the importance of mtDNA variation to toxicity remains unclear. Several studies have used transmitochondrial cybrid cells as personalised models with which to study the impact of mitochondrial genetic variation. Cybrids allow the effects of mtDNA to be assessed against a stable nuclear background and thus the in vitro elucidation of the fundamental mechanistic basis of such differences. Overall, the current evidence supports the tenet that mitochondrial genetics represent an exciting area within the field of personalised medicine and drug toxicity. However, further research effort is required to confirm its importance. In particular, efforts should focus upon translational research to connect preclinical and clinical data that can inform whether mitochondrial genetics can be useful to identify at risk individuals or inform risk assessment during drug development.

Purpose We designed the study to determine whether mitochondrial DNA (mtDNA) haplogroup, sequence, and heteroplasmy differed between individuals previously characterized as low (LR) or high responders (HR) as defined by their maximal oxygen uptake response to a standardized aerobic exercise training program. Methods DNA was isolated from whole blood in subjects from the HERITAGE Family Study that were determined to be either HR (n = 15) or LR (n = 15). mtDNA was amplified by long-range polymerase chain reaction, then tagged with Nextera libraries and sequenced on a MiSeq instrument. Results Different mtDNA haplogroup subtypes were found in HR and LR individuals. Compared with HR subjects, significantly more LR subjects had variants in 13 sites, including 7 in hypervariable (HV) regions: HV2 (G185A: 0 vs 6, P = 0.02; G228A: 0 vs 5, P = 0.04; C295T: 0 vs 6; P = 0.04), HV3 (C462T: 0 vs 5, P = 0.04; T489C: 0 vs 5; P = 0.04), and HV1 (C16068T: 0 vs 6, P = 0.02; T16125C: 0 vs 6, P = 0.02). Remaining variants were in protein coding genes, mtND1 (1 vs 8, P = 0.02), mtND3 (A10397G: 0 vs 5, P = 0.04), mtND4 (A11250G: 1 vs 8, P = 0.02), mtND5 (G13707A: 0 vs 5, P = 0.04), and mtCYTB (T14797C: 0 vs 5, P = 0.04; C15451A: 1 vs 8, P = 0.02). Average total numbers of heteroplasmies (P = 0.83) and frequency of heteroplasmies (P = 0.05) were similar between the groups. Conclusions Our findings provide specific sites across the mitochondrial genome that may be related to maximal oxygen uptake trainability.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that appears in at least one-third of adult carriers of FMR1 premutation. Several studies have shown that mitochondrial dysfunction may play a role in neurodegenerative disorders. In order to assess whether mitochondrial DNA variants are involved in the risk of developing FXTAS we evaluated the frequency of mitochondrial haplogroups in 132 unrelated Spanish FMR1 premutation carriers. In addition, the entire mitogenome of 26 FMR1 premutation carriers was sequenced using massively parallel sequencing technologies to analyze mitochondrial DNA variants. Statistical analyses reveal a significant difference in the frequency of T haplogroup. Data analysis of mitochondrial DNA sequences evidence an association between FXTAS and the burden of heteroplasmic variants as well as their distribution. Our results suggest that haplogroup T might be a potential protective factor for FXTAS and that FXTAS individuals accumulate higher rates of heteroplasmic variants in compromised regions of the mitochondrial genome. These results may explain, in part, the role of mitochondrial DNA in the development of FXTAS.

Mutations in mitochondrial DNA (mtDNA), especially in mitochondrial 12S rRNA and transfer RNA(tRNA)Ser(UCN) genes, are important causes of non‑syndromic hearing loss. However, the molecular mechanism underlying mt‑tRNA mutations in clinical hearing impairment are not fully understood. The present study assessed the molecular characterization of two Chinese families with non‑syndromic hearing loss, who both exhibited very low penetrance of deafness (9.1 and 12.5% for Family 1 and 2, respectively). Mutational analysis of the complete mtDNA genes identified the presence of cytochrome c oxidase 1/tRNASer(UCN) G7444A and tRNASer(UCN) C7492T mutations, together with polymorphisms belonging to human mitochondrial haplogroup D4 and G2b, respectively. Moreover, the G7444A and C7492T mutations occurred at highly conserved tRNASer(UCN) nucleotides and may cause tRNA metabolism failure, which is involved in mitochondrial translation defects. Therefore, the G7444A and C7492T mutations may lead to the mitochondrial dysfunction that responsible for deafness. However, the absence of any functional variants in Gap junction β‑2, Solute Carrier Family 26 Member 4 and TRNA 5‑methylaminomethyl‑2‑thiouridylate methyltransferase suggested that nuclear genes may not play active roles in the occurrence of deafness. In the present study, the observed incomplete penetrance of hearing loss and mild mitochondrial dysfunction indicated that mtDNA G7444A and C7492T mutations are insufficient to produce the deafness phenotype. Therefore, other risk factors such as environmental factors and epigenetic regulation may be involved in the pathogenesis of hearing loss in the families recruited in the present study.

ObjectiveReactive oxygen species are believed to be involved in the onset of RA, and the association between nuclear-encoded mitochondrial respiratory chain-related variants and RA has recently been revealed. However, little is known about the landscape of mitochondrial DNA (mtDNA) variants in RA.MethodsNext-generation sequencing was conducted to profile mtDNA germline and somatic variants in 124 RA patients and 123 age- and sex-matched healthy controls in the Taizhou area, China. Fisher’s exact test, SKAT and SKAT-O were used for gene-burden tests to investigate RA-related variants of mitochondrial genes. Predictive tools were applied to evaluate the pathogenicity of mtDNA variants, and mtDNA haplogroups were assigned according to mtDNA mutations recorded in PhyloTree database. The frequency distribution of mtDNA haplogroups between the groups was compared using χ2 analysis.ResultsWe identified 467 RA-unique and 341 healthy control-unique mtDNA variants, with 443 common variants. Only MT-ATP6 with a significant burden of variants was identified by Fisher’s exact test, SKAT and SKAT-O, even after Bonferroni adjustment, and the enrichment variants in MT-ATP6 was mainly driven by m.8830C>A, m.8833G>C and m.8843T>A variants. Besides, four frequently low-heteroplasmic variants including the three variants above and m.14135T>G of MT-ND5 were detected in RA only; except for m.8830C>A, they are considered potential pathogenicity based on functional predictions. χ2 analysis before Bonferroni adjustment revealed haplogroup F1/F1a to be negatively associated with RA (P ConclusionThese results profiled the landscape of germline and somatic mtDNA variants in RA and supported the effects of mitochondrial genes on RA.

Background Neuroblastoma is a childhood malignancy that arises from the developing sympathetic nervous system. Although mitochondrial dysfunctions have been implicated in the pathophysiology of neuroblastoma, the role of mitochondrial DNA (mtDNA) has not been extensively investigated. Methods A total of 2404 Caucasian children diagnosed with neuroblastoma and 9310 ancestry-matched controls were recruited at the Children’s Hospital of Philadelphia. The mtDNA haplogroups were identified from SNP array data of two independent cohorts. We conducted a case-control study to explore potential associations of mtDNA haplogroups with the susceptibility of neuroblastoma. The genetic effect of neuroblastoma was measured by odds ratios (ORs) of mitochondrial haplogroups. All tests were two-sided. Results Haplogroup K was statistically significantly associated with reduced risk of neuroblastoma in the discovery cohort consisting of 1474 cases and 5699 controls (OR = 0.72, 95% confidence interval [CI] = 0.57 to 0.90; P = 4.8 × 10-3). The association was replicated in an independent cohort (OR = 0.69, 95% CI = 0.53 to 0.92; P = .01) of 930 cases and 3611 controls. Pooled analysis was performed by combining the two data sets. The association remained highly statistically significant after correction for multiple testing (OR = 0.71, 95% CI = 0.59 to 0.84, P = 1.96 × 10-4, Pcorrected = .002). Further analysis focusing on neuroblastoma subtypes indicated haplogroup K was more associated with high-risk neuroblastoma (OR = 0.57, 95% CI = 0.43 to 0.76; P = 1.46 × 10–4) than low-risk and intermediate-risk neuroblastoma. Conclusions Haplogroup K is an independent genetic factor associated with reduced risk of developing neuroblastoma in European descents. These findings provide new insights into the genetic basis of neuroblastoma, implicating mitochondrial DNA encoded proteins in the etiology of neuroblastoma.

Mitochondrial DNA (mtDNA) is a useful tool in forensic investigation as it provides information about the matrilineal ancestry of individuals. In addition, mtDNA can be analyzed when the analysis of other nuclear markers is underperforming. Recently, we developed a minisequencing panel for the simultaneous analysis of 52 mtDNA SNPs to classify maternal lineages into the main haplogroups and their phylogeographic origin. In order to make this panel suitable for forensic genetics laboratories, a validation study has been performed in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines, including species specificity, reproducibility, sensitivity, and stability tests. The results demonstrate that the panel of 52 mtDNA SNPs is highly sensitive, since it enables to obtain complete genetic profiles of samples containing minimal amounts of DNA (1 pg). Furthermore, it provides sufficient genetic information to detect the matrilineal biogeographical origin of highly degraded samples, i.e., ancient dating skeletal remains, and samples with the presence of inhibitors, such as hematin and humic acid. In addition, this panel can detect mixtures in samples whose mtDNA haplogroups of contributors are different. Overall, the results of this study demonstrate the suitability of this minisequencing panel of 52 mtDNA SNPs to be used in forensic cases, with samples of low amount or degraded DNA.

This study reports the mitochondrial DNA haplogroup M diversity in two tribal populations of South India. The aim of this study was to analyze and establish a mitochondrial profile to know the genetic origin and relatedness of people of India. MtDNA variability of the complete mitochondrial genome was analyzed by the Sanger sequencing method. Our results revealed novel sub-lineages of haplogroup: M2, M3, M6, M35, M65, and an M* lineage, indicating a deep in-situ origin and spread of haplogroup M lineages in India, shared with many tribal and caste populations.

Mitochondrial genes' variants encoded in both the nuclear and mitochondrial genomes can disrupt mitochondrial function, resulting in losing of cartilage and generating osteoarthritis (OA). However, the association between mtDNA haplogroups and OA still lacks strength evidence supporting. The aim of this meta-analysis is to assess the role of mtDNA haplogroups in speculating the pathogenesis and progression of OA. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and World Health Organization clinical trials' registry center were searched to identify relevant studies up to the end of March 2019. Inclusion citations required a case-control or cohort study to demonstrate the association between mtDNA haplogroups and OA's prevalence or progression. Title, abstract, and full-text screening were sequentially assessed by three reviewers. Data were analyzed using STATA. Besides, publication bias and meta-regression analysis were conducted to explore potential heterogeneities. We collected results from 7 articles. The cluster TJ cases showed a lower proportion in OA cases (RR = 0.83, 95% CI 0.72, 0.96). However, there is no evidence that revealed this kind of impact originated from neither type J nor type T individually. Besides, the type B and G analyses among Asian populations also elucidated a negative association. Moreover, the cluster TJ of mtDNA haplogroups revealed a lower cumulative probability of radiographic OA progression (ES = 0.77, 95% CI 0.63, 0.94), which was contributed by type T (ES = 0.61, 95% CI 0.45, 0.82).The mtDNA haplogroups do have impacts on the prevalence and progression of OA. Cluster TJ could help reduce the prevalence and slow down the radiographic changes; however, the impacts came from type J and type T, respectively.

We have studied by SEM-EDX some hairs from a lock of hair of the Queen Marie-Antoinette kept in a medallion. These hairs are thin and of ash blond colour. The mtDNA haplogroup of these hairs is a rare sub-clade of H, characterized by mutations 152C, 194T, 263G, and 315.1 C in the HVR2 region of the mtDNA sequence.Read Complete Article at ijSciences: V92020052335 AND DOI: http://dx.doi.org/10.18483/ijSci.2335

Aim.To identify associations of mtDNA polymorphisms with sudden cardiac death.Materials and Methods.DNA was isolated from the cardiac tissue excised during the autopsy from individuals who died from sudden cardiac death (n = 260). The frequencies of the most common European mtDNA haplogroups (H, U, T and J) were determined using restriction fragment length polymorphism analysis. In addition, we performed a comparative analysis using previously published data on mtDNA polymorphisms in the West Siberian population.Results.The distribution of mtDNA haplogroups in the patients who died from sudden cardiac death was similar as in the general population: 40% for haplogroup H, 23% for haplogroup U, 12% for haplogroup T and 6.5% for haplogroup J. We found no significant differences regarding the frequency of mtDNA haplogroups in individuals who died from sudden cardiac death and the population level.Conclusion.We discovered no associations of H, U, T, and J mtDNA haplogroups with sudden cardiac death. These results indicate the necessity of a detailed analysis of mitochondrial genome to determine mtDNA variants associated with sudden cardiac death.

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

Background Mitochondria have been shown to play vital roles during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) development. Currently, it is unclear whether mitochondrial DNA (mtDNA) variants, which define mtDNA haplogroups and determine oxidative phosphorylation performance and reactive oxygen species production, are associated with COVID-19 risk. Methods A population-based case–control study was conducted to compare the distribution of mtDNA variations defining mtDNA haplogroups between healthy controls (n = 615) and COVID-19 patients (n = 536). COVID-19 patients were diagnosed based on molecular diagnostics of the viral genome by qPCR and chest X-ray or computed tomography scanning. The exclusion criteria for the healthy controls were any history of disease in the month preceding the study assessment. MtDNA variants defining mtDNA haplogroups were identified by PCR-RFLPs and HVS-I sequencing and determined based on mtDNA phylogenetic analysis using Mitomap Phylogeny. Student’s t-test was used for continuous variables, and Pearson’s chi-squared test or Fisher’s exact test was used for categorical variables. To assess the independent effect of each mtDNA variant defining mtDNA haplogroups, multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) with adjustments for possible confounding factors of age, sex, smoking and diseases (including cardiopulmonary diseases, diabetes, obesity and hypertension) as determined through clinical and radiographic examinations. Results Multivariate logistic regression analyses revealed that the most common investigated mtDNA variations (> 10% in the control population) at C5178a (in NADH dehydrogenase subunit 2 gene, ND2) and A249d (in the displacement loop region, D-loop)/T6392C (in cytochrome c oxidase I gene, CO1)/G10310A (in ND3) were associated with a reduced risk of severe COVID-19 (OR = 0.590, 95% CI 0.428–0.814, P = 0.001; and OR = 0.654, 95% CI 0.457–0.936, P = 0.020, respectively), while A4833G (ND2), A4715G (ND2), T3394C (ND1) and G5417A (ND2)/C16257a (D-loop)/C16261T (D-loop) were related to an increased risk of severe COVID-19 (OR = 2.336, 95% CI 1.179–4.608, P = 0.015; OR = 2.033, 95% CI 1.242–3.322, P = 0.005; OR = 3.040, 95% CI 1.522–6.061, P = 0.002; and OR = 2.890, 95% CI 1.199–6.993, P = 0.018, respectively). Conclusions This is the first study to explore the association of mtDNA variants with individual’s risk of developing severe COVID-19. Based on the case–control study, we concluded that the common mtDNA variants at C5178a and A249d/T6392C/G10310A might contribute to an individual’s resistance to developing severe COVID-19, whereas A4833G, A4715G, T3394C and G5417A/C16257a/C16261T might increase an individual’s risk of developing severe COVID-19.

The growing number of next-generation sequencing (NGS) data presents a unique opportunity to study the combined impact of mitochondrial and nuclear-encoded genetic variation in complex disease. Mitochondrial DNA variants and in particular, heteroplasmic variants, are critical for determining human disease severity. While there are approaches for obtaining mitochondrial DNA variants from NGS data, these software do not account for the unique characteristics of mitochondrial genetics and can be inaccurate even for homoplasmic variants. We introduce MitoScape, a novel, big-data, software for extracting mitochondrial DNA sequences from NGS. MitoScape adopts a novel departure from other algorithms by using machine learning to model the unique characteristics of mitochondrial genetics. We also employ a novel approach of using rho-zero (mitochondrial DNA-depleted) data to model nuclear-encoded mitochondrial sequences. We showed that MitoScape produces accurate heteroplasmy estimates using gold-standard mitochondrial DNA data. We provide a comprehensive comparison of the most common tools for obtaining mtDNA variants from NGS and showed that MitoScape had superior performance to compared tools in every statistically category we compared, including false positives and false negatives. By applying MitoScape to common disease examples, we illustrate how MitoScape facilitates important heteroplasmy-disease association discoveries by expanding upon a reported association between hypertrophic cardiomyopathy and mitochondrial haplogroup T in men (adjusted p-value = 0.003). The improved accuracy of mitochondrial DNA variants produced by MitoScape will be instrumental in diagnosing disease in the context of personalized medicine and clinical diagnostics., Author summary Recent studies have highlighted the importance of mitochondrial DNA variation in both primary mitochondrial disease and complex, human pathology including COVID-19, and space-flight stress. The vast amount of existing, next-generation sequencing (NGS) data can be leveraged to interrogate both nuclear and mitochondrial DNA (mtDNA) sequence simultaneously, allowing for analysis of the interplay between mitochondrial and nuclear encoded genes in mitochondrial function. Identifying mtDNA sequence accurately is complicated by the presence of nuclear encoded mitochondrial sequences (NUMTs), which are homologous to mtDNA. Current software for analyzing mtDNA from NGS do not accurately model the unique characteristics of mitochondrial genetics. We introduce MitoScape, a novel, big-data, software which models mitochondrial genetics through machine learning to accurately identify mtDNA sequence from NGS data. MitoScape takes advantage of rho-zero cell data to model the characteristics of NUMTs. We show that MitoScape produces more accurate heteroplasmy estimates compared to published software. We provide an example of applying MitoScape in replicating an association between hypertrophic cardiomyopathy and mitochondrial haplogroup T in men. MitoScape is an important contribution to mitochondrial genomics allowing for accurate mtDNA variants, and the ability to tailor mtDNA analysis in different population and disease contexts, which is not available in other software.

Background Mitochondrial haplogroup assignment is an important tool for forensics and evolutionary genetics. African populations are known to display a high diversity of mitochondrial haplogroups. In this research we explored mitochondrial haplogroup assignment in African populations using commonly used genome-wide SNP arrays. Results We show that, from eight commonly used SNP arrays, two SNP arrays outperform the other arrays when it comes to the correct assignment of African mitochondrial haplogroups. One array enables the recognition of 81% of the African mitochondrial haplogroups from our compiled dataset of full mitochondrial sequences. Other SNP arrays were able to assign 4–62% of the African mitochondrial haplogroups present in our dataset. We also assessed the performance of available software for assigning mitochondrial haplogroups from SNP array data. Conclusions These results provide the first cross-checked quantification of mitochondrial haplogroup assignment performance from SNP array data. Mitochondrial haplogroup frequencies inferred from most common SNP arrays used for human population analysis should be considered with caution.

Hypertensive African Americans have ~50% response rate to thiazide diuretic treatment. This contributes to a high prevalence of uncontrolled high blood pressure. Here, we examine the role the mitochondrial genome has on thiazide diuretic treatment response in hypertensive African Americans enrolled in a clinical trial. Participants from the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT, n= 4279) were genotyped using the Illumina Infinium Multi-Ethnic Beadchip. Haplotype groups were called using HaploGrep. We used linear regression analysis to examine the association between mitochondrial haplogroups (L, M, and N) and change in blood pressure and change in fasting glucose over 6 months and two years, respectively. The analysis revealed a null association between mitochondrial haplogroups M and N vs. L for each of the outcomes. In subgroup analysis, the L subclades L1, L2, and L3/L4 (vs. L0) were each inversely associated with fasting glucose response (p < 0.05). This discovery analysis suggests the mitochondrial genome has a small effect on fasting glucose but not blood pressure response to thiazide diuretic treatment in African Americans.

OBJECTIVES We aimed to contribute to the understanding of the ancient geographic origins of the uniparentally inherited markers in modern admixed Argentinian populations from central Patagonia with new information provided for the city of Trelew. We attempted to highlight the importance of combining different genetic markers when studying population history. METHODS The mtDNA control region sequence was typified in 89 individuals and 12 Y-STR and 15 Y-SNP loci were analyzed in 66 males. With these data, analysis of molecular variance and Network analyses were carried out. We exhaustively compared the modern data with ancient mtDNA information. Finally, we tested the differences in continental origins estimated by uniparental and previously published biparental markers. RESULTS Native American mtDNAs (53.9%) increased when maternal ancestors were born in the northern (81.8%) and southern (58.5%) regions of Argentina or in Chile (77.8%). Population substructure was only observed for Y-chromosome haplotypes. Some mtDNA haplogroups have been present in the area for at least ca. 2762-2430 and ca. 500 (D1g and D1g4 haplogroups) and ca. 6736 and ca. 6620 (C1b and C1c haplogroups) years, respectively. In contrast, haplogroups B2i2 and C1b13, frequent in modern Patagonia populations, had not been found in previous ancient DNA studies of the region. CONCLUSIONS The results suggest that Native American ancestry is well preserved in the region. Trelew samples had characteristic native mtDNA haplogroups previously described in Chilean and Argentine Patagonian populations, but not observed in ancient samples until now. These findings support the idea that these lineages have a recent regional origin. Finally, the estimated proportions of continental ancestry depend on the genetic marker analyzed.

Mitochondria are essential organelles that are not only responsible for energy production but are also involved in cell metabolism, calcium homeostasis, and apoptosis. Targeting mitochondria is a key strategy for bacteria to subvert host cells’ physiology and promote infection. Helicobacter (H.) pylori targets mitochondria directly. However, mitochondrial genome (mtDNA) polymorphism (haplogroup) is not yet considered an important factor for H. pylori infection. Here, we clarified the association of mitochondrial haplogroups with H. pylori prevalence and the ability to perform damage. Seven mtDNA haplogroups were identified among 28 H. pylori-positive subjects. Haplogroup B was present at a higher frequency and haplotype D at a lower one in the H. pylori population than in that of the H. pylori-negative one. The fibroblasts carrying high-frequency haplogroup displayed a higher apoptotic rate and diminished mitochondrial respiration following H. pylori infection. mtDNA mutations were accumulated more in the H. pylori-positive population than in that of the H. pylori-negative one in old age. Among the mutations, 57% were located in RNA genes or nonsynonymous protein-coding regions in the H. pylori-positive population, while 35% were in the H. pylori-negative one. We concluded that gastric disease caused by Helicobacter virulence could be associated with haplogroups and mtDNA mutations.

The identity of the mummified Lady from the Barfusser Church in Basel, Switzerland has been unsolved for decades, despite the prominent location of the burial place in front of the choir screen. A recent multidisciplinary research approach came up with a possible candidate, Anna Catharina Bischoff who died in Basel in 1787 with an age of 69 years (1719–1787). To verify the identity of the mummy, genealogists of the Citizen Science Basel discovered three living individuals of the maternal lineage of two different family branches, separated from Anna Catharina Bischoff by up to 22 generations. In this study we compare the ancient mitochondrial DNA of the mummy recovered from a premolar to the mitochondrial DNA of these three candidates. Initially the mitochondrial hypervariable regions I and II of the living individuals were screened using the Sanger sequencing method. This was followed by a mitochondrial capture approach and next generation sequencing to enrich for the whole mitochondrial genome of the mummy and one living person. A full mitochondrial genome has been recovered of both individuals sharing an identical haplotype. The sequence was assigned to the mitochondrial haplogroup U5a1+!16192 including two private mutations 10006G and 16293C. Only by using an interdisciplinary approach combining ancient DNA analysis and genealogy a maternal lineage of a non-noble family spanning 22 generations could be confirmed.

Databases of allele frequency are extremely helpful for evaluating clinical variants of unknown significance; however, until now, genetic databases such as the Genome Aggregation Database (gnomAD) have ignored the mitochondrial genome (mtDNA). Here we present a pipeline to call mtDNA variants that addresses three technical challenges: (i) detecting homoplasmic and heteroplasmic variants, present respectively in all or a fraction of mtDNA molecules, (ii) circular mtDNA genome, and (iii) misalignment of nuclear sequences of mitochondrial origin (NUMTs). We observed that mtDNA copy number per cell varied across gnomAD cohorts and influenced the fraction of NUMT-derived false-positive variant calls, which can account for the majority of putative heteroplasmies. To avoid false positives, we excluded samples prone to NUMT misalignment (few mtDNA copies per cell), cell line artifacts (many mtDNA copies per cell), or with contamination and we reported variants with heteroplasmy greater than 10%. We applied this pipeline to 56,434 whole genome sequences in the gnomAD v3.1 database that includes individuals of European (58%), African (25%), Latino (10%), and Asian (5%) ancestry. Our gnomAD v3.1 release contains population frequencies for 10,850 unique mtDNA variants at more than half of all mtDNA bases. Importantly, we report frequencies within each nuclear ancestral population and mitochondrial haplogroup. Homoplasmic variants account for most variant calls (98%) and unique variants (85%). We observed that 1/250 individuals carry a pathogenic mtDNA variant with heteroplasmy above 10%. These mitochondrial population allele frequencies are publicly available at gnomad.broadinstitute.org and will aid in diagnostic interpretation and research studies.

Kazakhstan covers a vast territory, and it has always been a land of nomadic pastoralism, where domesticated horses and sheep were moved by nomadic people across the steppe. Previous reports suggest that sheep breeds from Kazakhstan have an intermediate genetic composition between Asian and European breeds; however, this data appears to be limited. Therefore, we studied the genetic diversity of ancient domestic sheep from two Late Bronze Age settlements, Toksanbai and Kent, located in the Pre-Caspian region of Kazakhstan and central Kazakhstan, respectively. We have applied ZooMS analysis for taxonomic identification of small ruminant remains to select ancient specimens of domestic sheep (Ovis aries). To assign sheep mitochondrial DNA (mtDNA) haplogroups, the single nucleotide polymorphisms (SNPs) from the control region were analyzed by real-time PCR and direct sequencing. Identical distribution of mtDNA haplogroups A (8/14; 57%), B (5/14; 36%), and C (1/14; 7%) was observed in the specimens from Toksanbai (n = 14) and Kent (n = 14). Ovine haplogroup A was predominant in both settlements. Both archeological sites had similar patterns of haplogroup distribution, indicating early sheep introduction into the region. These results are important to gain a better understanding of sheep migrations in the Eurasian steppe and highlight the importance of genomic analysis of earlier local lineages., Haplotyping; aDNA; Mitochondrial DNA; ZooMS; Bronze age; Kazakhstan; Sheep; Ovis aries.

We used a linear autoencoder (LAE) and its learning dynamics to analyze the high-order structure of human mitochondrial DNA (mtDNA). A total of 360 complete human mtDNA sequences were collected from the MITOMAP database and transformed into 1024-dimensional vectors of pentanucleotide frequencies. We compressed those into a three-dimensional (3D) coordinates by an LAE at each step of training by gradient descent with respect to the quadratic error function. Along the time axis of training epochs, the compressed 3D coordinates were gradually clustered and separated in accordance with the order of the genetic distance in the phylogenetic tree of human mtDNA haplogroups. This suggests that there is an association between the learning dynamics of LAE and the high-dimensional structure of human mtDNA sequences, similar to that of phylogenetic analysis and evolutionary pathways: the five clusters eventually contained only a single haplogroup of L0, M, N, R, and U, while the L3 cluster contained a small number of M members and The packing was comparable to that realized in learning dynamics similar to genetic classification and evolutionary pathways by LAE in principal component analysis (PCA), but somewhat denser than PCA.

Background A Southwest Asian origin and dispersal to North Africa in the Early Upper Palaeolithic era has been inferred in previous studies for mtDNA haplogroups M1 and U6. Both haplogroups have been proposed to show similar geographic patterns and shared demographic histories. Results We report here 24 M1 and 33 U6 new complete mtDNA sequences that allow us to refine the existing phylogeny of these haplogroups. The resulting phylogenetic information was used to genotype a further 131 M1 and 91 U6 samples to determine the geographic spread of their sub-clades. No southwest Asian specific clades for M1 or U6 were discovered. U6 and M1 frequencies in North Africa, the Middle East and Europe do not follow similar patterns, and their sub-clade divisions do not appear to be compatible with their shared history reaching back to the Early Upper Palaeolithic. The Bayesian Skyline Plots testify to non-overlapping phases of expansion, and the haplogroups’ phylogenies suggest that there are U6 sub-clades that expanded earlier than those in M1. Some M1 and U6 sub-clades could be linked with certain events. For example, U6a1 and M1b, with their coalescent ages of ~20,000–22,000 years ago and earliest inferred expansion in northwest Africa, could coincide with the flourishing of the Iberomaurusian industry, whilst U6b and M1b1 appeared at the time of the Capsian culture. Conclusions Our high-resolution phylogenetic dissection of both haplogroups and coalescent time assessments suggest that the extant main branching pattern of both haplogroups arose and diversified in the mid-later Upper Palaeolithic, with some sub-clades concomitantly with the expansion of the Iberomaurusian industry. Carriers of these maternal lineages have been later absorbed into and diversified further during the spread of Afro-Asiatic languages in North and East Africa.

Mitochondria are central eukaryotic organelles in cellular metabolism and ATP production. Mitochondrial DNA (mtDNA) alterations have been implicated in the development of colorectal cancer (CRC). However, there are few reports on the association between mtDNA haplogroups or single nucleotide polymorphisms (SNPs) and the risk of CRC. The mtDNA of 286 Northern Han Chinese CRC patients were sequenced by next‐generation sequencing technology. MtDNA data from 811 Han Chinese population controls were collected from two public data sets. Then, logistic regression analysis was used to determine the effect of mtDNA haplogroup or SNP on the risk of CRC. We found that patients with haplogroup M7 exhibited a reduced risk of CRC when compared to patients with other haplogroups (odds ratio [OR] = 0.532, 95% confidence interval [CI] = 0.285–0.937, p = 0.036) or haplogroup B (OR = 0.477, 95% CI = 0.238–0.916, p = 0.030). Furthermore, haplogroup M7 was still associated with the risk of CRC when the validation and combined control cohort were used. In addition, several haplogroup M7 specific SNPs, including 199T>C, 4071C>T and 6455C>T, were significantly associated with the risk of CRC. Our results indicate the risk potential of mtDNA haplogroup M7 and SNPs in CRC in Northern China.

Aims/Introduction Identifying diabetes‐susceptible genetic variants will help to provide personalized therapy for the management of type 2 diabetes. Previous studies have reported a genetic risk score (GRS), computed by the sum of nuclear DNA (nDNA) risk alleles, that may predict the future requirement for insulin therapy. Although mitochondrial dysfunction has a close association with insulin resistance (IR), there are few studies investigating whether genetic variants of mitochondrial DNA (mtDNA) will affect the clinical characteristics of type 2 diabetes. Materials and Methods Mitochondrial haplogroups were determined using mtDNA whole genome next generation sequencing and 13 single nucleotide polymorphisms (SNPs) in nDNA susceptibility loci of 13 genes in 604 Taiwanese subjects with type 2 diabetes. A GRS of nDNA was computed by summation of the number of risk alleles. The correlation between the mtDNA haplogroup and the clinical characteristics of type 2 diabetes was assessed by logistic regression analysis. The results were compared with the GRS subgroups for the risk of insulin requirement. Results Mitochondrial haplogroups modulate the clinical characteristics of type 2 diabetes, in which patients harboring haplogroup D4, compared with those harboring non‐D4 haplotypes, were less prone to require insulin treatment, after adjusting for age, gender, and diabetes duration. However, there was no association between insulin requirement and GRS calculated from nuclear genetic variants. Conclusions Mitochondrial haplogroups, but not nuclear genetic variants, have a better association with the insulin requirement. The results highlight the role of mitochondria in the management of common metabolic diseases., Mitochondrial haplogroups, but not nuclear genetic variants, have a better association with the insulin requirement in patients with T2DM.

Mitochondrial DNA (mtDNA) analysis is an important source of information about biogeographical mother lineage origin of the individuals. Furthermore, when we face up degraded DNA samples, many times mtDNA is the only source of genetic information. Even, sometimes, this genetic marker could provide information about kinship through maternal lineage. This study is focused on 14 archaeological individuals from the Segobriga archaeological site (Saelices, Cuenca, central-eastern Spain). The relevance of Segobriga is that it has been occupied from the V century B.C. by different human populations throughout ten centuries; from the Roman Imperial period of the Iberian Peninsula, until the end of the Muslim period. So that, the 14 selected individuals belong to different periods within the total time of occupation of the site; concretely there were selected: five from the Muslim period, seven from Late Roman period, one Visigoth and one individual without a precise chronology assigned. We have studied the HVI and HVII mitochondrial DNA regions, by the amplification of short overlapping fragments. The objectives of this analysis were: the search of the biogeographical origin of the individuals, and the establishment of comparisons among the different chronological groups, including nowadays population of the region, trying to evaluate the genetic contribution of the past populations in the current population. We have obtained HVI and HVII regions mtDNA profiles in 8 of the 14 individuals, establishing their mtDNA haplogroup; and only partial HVII region mitochondrial DNA profiles in 5 of them. All the individuals shown typical European mtDNA haplogroups (H2a2a1g, H5, H5a, K, U5a, U5b1c, T2e, H), some of them with significant nowadays presence in Middle East (T2e, U5b1c, U5a and H5).

The finding of a multiple simultaneous burial often suggests a close biological relationship among the individuals. In this context, this paper focuses on three very closely interred sub-adults in the site of El Cerro (La Horra, Burgos, Spain), a pit site of the Central Iberian Plateau dated to the Middle Bronze Age, ca. 1850-1450 cal BC. In this simultaneous triple burial two of the subadults were inhumed in lateral decubitus position intertwined face to face: a 7–8 years-old infant placed on his right side (HOR 02) and a second infant, perhaps male, about 11 years old, on the left (HOR 03), keeping a purposefully symmetrical disposition. On top of these corpses, and occupying the space between them, was placed a third subadult (HOR 01), a juvenile of 11–15 years, probably female. We have selected different teeth samples from each one of these individuals for genetic analysis, with the aim of enlightening their alleged kinship relationship, which could be key in the interpretation of the site and the overall cultural practices. To perform the kinship analysis, we have extracted and amplified DNA from three dental pieces from individuals HOR01 and HOR02, and two from HOR03. The DNA markers analysed were autosomal short tandem repeats (STRs), autosomal insertion – deletion markers (InDels) and HVI and HVII regions of mitochondrial DNA (mtDNA). Nevertheless, the poor preservation state of the DNA did not allow the obtention of reliable results autosomal markers. However, the mitochondrial DNA analysis provide the same haplotype to the three individuals (16298C 64T 72C, in the range: (16105–16399) (57–128)), belonging to HV0 mitochondrial haplogroup. The results point to a kinship among all the individuals through the maternal lineage.

The objective of the study was to investigate the association between mitochondrial DNA (mtDNA) mutations and essential hypertension (EH). One Han Chinese pedigree with maternally inherited EH was recruited in the current study. The matrilineal relatives from this family underwent clinical, genetic, and molecular analysis. Moreover, the mtDNA gene mutations were screened by PCR and direct Sanger sequence. Evolutionary conservation was performed and the secondary structure of mt-tRNASer(UCN) with and without the 7471delC was evaluated by the RNA Fold Webserver program. Moreover, the pathogenicity scoring system was used to assess the 7471delC. This Chinese pedigree exhibited a relative high penetrance and expressivity of EH. Of 13 matrilineal relatives, 5 of them suffered from high blood pressure (BP). Genetic analysis of the complete mtDNA genes showed the presence of a novel tRNASer(UCN) 7471delC, together with a set of polymorphisms belonging to the human mitochondrial haplogroup G2a1. In fact, the 7471delC occurred within the T-stem and extra arm of tRNASer(UCN), which was very conserved from bacteria to human mitochondria. Interestingly, the 7472insC which was located at the same position had been regarded as a pathogenic mutation associated with non-syndromic hearing loss. In addition, bioinformatics analysis revealed that the 7471delC affected the secondary structure of tRNASer(UCN). The pathogenicity scoring system showed that the 7471delC may be “possibly pathogenic” associated with EH. We believed that the 7471delC may impair the mitochondrial functional and played an active role in the pathogenesis of EH in this pedigree. The 7471delC may be a novel risk factor for maternally transmitted EH.

Certain mutations in mitochondrial DNA (mtDNA) are associated with Leber's hereditary optic neuropathy (LHON). In particular, the well‑known NADH dehydrogenase 4 (ND4) m.11778G>A mutation is one of the most common LHON‑associated primary mutations worldwide. However, how specific mtDNA mutations, or variants, affect LHON penetrance is not fully understood. The aim of the current study was to explore the relationship between mtDNA mutations and LHON, and to provide useful information for early detection and prevention of this disease. Following the molecular characterization of a Han Chinese family with maternally inherited LHON, four out of eight matrilineal relatives demonstrated varying degrees of both visual impairment and age of onset. Through PCR amplification of mitochondrial genomes and direct Sanger sequencing analysis, a homoplasmic mitochondrial‑encoded ND4 m.11778G>A mutation, alongside a set of genetic variations belonging to human mtDNA haplogroup B5b1 were identified. Among these sequence variants, alanine transfer RNA (tRNA)Ala m.5601C>T was of particular interest. This variant occurred at position 59 in the TψC loop and altered the base pairing, which led to mitochondrial RNA (mt‑RNA) metabolism failure and defects in mitochondrial protein synthesis. Bioinformatics analysis suggested that the m.5601C>T variant altered tRNAAla structure. Therefore, impaired mitochondrial functions caused by the ND4 m.11778G>A mutation may be enhanced by the mt‑tRNAAla m.5601C>T variant. These findings suggested that the tRNAAla m.5601C>T variant might modulate the clinical manifestation of the LHON‑associated primary mutation.

BackgroundHelicobacter pylori, a bacterium that infects the human stomach, has high genetic diversity. Because its evolution is parallel to human,H. pyloriis used as a tool to trace human migration. However, there are few studies about the relationship between phylogeography ofH. pyloriand its host human.MethodsWe examined bothH. pyloriDNA and the host mitochondrial DNA and Y-chromosome DNA obtained from a total 119 patients in the Dominican Republic, where human demography consists of various ancestries. DNA extracted from culturedH. pyloriwere analyzed by multi locus sequence typing. Mitochondrial DNA and Y-chromosome DNA were evaluated by haplogroup analyses.ResultsH. pyloristrains were divided into 2 populations; 68 strains with African group (hpAfrica1) and 51 strains with European group (hpEurope). In Y-chromosomal haplogroup, European origin was dominant, whereas African origin was dominant both inH. pyloriand in mtDNA haplogroup. These results supported the hypothesis that mother-to-child infection is predominant inH. pyloriinfection. The Amerindian type of mtDNA haplogroup was observed in 11.8% of the patients; however, Amerindian type (hspAmerind) ofH. pyloriwas not observed. Although subpopulation type of most hpAfrica1 strains in Central America and South America were hybrid (hspWAfrica/hpEurope), most Dominican Republic hpAfrica1 strains were similar to those of African continent.ConclusionsGenetic features ofH. pylori, mtDNA, and Y haplogroups reflect the history of colonial migration and slave trade in the Dominican Republic. Discrepancy betweenH. pyloriand the host human genotypes support the hypothesis that adaptability of hspAmerindH. pyloristrains are weaker than hpEurope strains.H. pyloristrains in the Dominican Republic seem to contain larger proportion of African ancestry compared to other American continent strains.

The mitochondrial genome plays an important role in energy production and cells functions control. Therefore, it can affect the traits which are significant for selection of farm animals. The published data allow assuming that the mtDNA variability in pigs is one of the ways to assess and predict the breeding and productive qualities. The aim of our work was to determine the mtDNA haplotypes by the D-loop region sequencing and evaluate their associations with the selection features in pigs. Studies were carried out on landrace sows (n = 2626) bred in the Russian Federation. We estimated the Muscle Depth and the Percent Meat. As a result, three mtDNA haplogroups (C, D, and E) were identified. In the studied group of pigs, haplotype E was determined in 1378 sows (52.5%) and had the highest frequency. Haplotype D was detected in 1064 sows (40.6%). In general, haplotypes of European origin were more common in our population. Among the haplotypes of Asian origin (including A, B, and C), only haplotype C was identified in our group of pigs. It was determined in 182 sows (6.9%). Haplotypes A and B were not identified. Analysis of variance (ANOVA) has demonstrated the significance of differences in the haplotypes of the mtDNA regarding the studied traits of meat productivity in sows. These facts confirm the prospects of mtDNA studies as determinants of pig productivity. Our results have shown that some haplotypes of mtDNA are largely related to phenotypic traits.

Mitochondrial DNA (mtDNA) haplogroups are associated with various types of cancer; however, the molecular mechanisms by which mtDNA haplogroups affect primary hepatocellular carcinoma (HCC) are not known. In this study, we carried out a case-control study on 388 HCC patients and 511 geographically matched asymptomatic control subjects in northern China. We found that mtDNA haplogroup N9a and its diagnostic SNP, m.16257C > A, negatively correlated with the incidence of HCC in northern China (odds ratio [OR] 0.290, 95% confidence interval [CI] 0.123–0.685, p = 0.005), particularly in patients with infection of hepatitis B/C virus (HBV/HCV) (for haplogroup N9a: OR 0.213, 95% CI 0.077–0.590, p = 0.003; for m.16257C > A: OR 0.262, 95% CI 0.107–0.643, p = 0.003). However, mtDNA haplogroup N9a is not associated with clinical characteristics of HCC including serum alpha-fetoprotein (AFP) level and tumor size. In addition, cytoplasmic hybrid (cybrid) cells with N9a haplogroup (N9a10a and N9a1) had transcriptome profiles distinct from those with non-N9a (B5, D4, and D5) haplogroups. Gene set enrichment analysis (GSEA) showed that metabolic activity varied significantly between N9a and non-N9a haplogroups. Moreover, cells with haplogroup N9a negatively correlated with cell division and multiple liver cancer pathways compared with non-N9a cells. Although it is still unclear how N9a affects the aforementioned GSEA pathways, our data suggest that mtDNA haplogroup N9a is negatively correlated with the incidence and progression of HCC in northern China. Keywords: mitochondrial DNA, mtDNA, haplogroup, mitochondrial SNP, mtSNP, hepatocellular carcinoma, cybrid, gene set enrichment analysis, GSEA