Search Results (176)

Pancreatic cancer (PC) is a highly aggressive malignancy characterized by limited opportunities for early diagnosis and poor clinical outcomes, underscoring the need for minimally invasive biomarkers to improve detection and patient stratification. Given emerging evidence that mitochondrial DNA (mtDNA) alterations reflect cancer-related biological processes, this study investigated whether blood-derived mtDNA profiles could provide clinically relevant information in PC. In this exploratory study, whole-blood mtDNA from 33 PC patients and 10 healthy individuals were analyzed using next-generation sequencing to assess single-nucleotide variants (SNVs), allele frequencies, and mtDNA copy number. A total of 252 unique mtDNA SNVs were identified, including variants exclusive to PC patients, variants unique to controls, and variants shared between groups. While the overall SNV burden did not differ significantly between groups, PC patients showed distinct mutation distributions and allele frequency patterns, with cancer-exclusive variants occurring predominantly at low allele frequencies. Mutation hotspots were observed in the ND5, COI, and D-loop regions, implicating genes involved in oxidative phosphorylation and mtDNA maintenance. Although mtDNA copy number did not differ significantly between groups, greater variability was observed among PC patients and was associated with differences in survival outcomes. Overall, these findings indicate that blood-based mtDNA profiling captures biologically relevant variation associated with PC and supports further development of integrated mtDNA-based approaches for improved risk assessment and patient stratification. Full article

Background/Objectives: Non-coding RNAs provide new chances of targeting multiple oncogenic pathways. Many long non-coding RNAs (lncRNAs) are being characterized as relevant in cancer initiation, progression, and recurrence. Mitochondrial D-loop 1 antisense lncRNA (MDL1AS) is a novel lncRNA that might be important in cancer development, so the aim of this project was to understand its function in differently differentiated cancer cells. Methods: The effects of MDL1AS downregulation on the cellular behavior of NTERA2 and SH-SY5Y cell lines were studied. Results: MDL1AS reduction inhibited oxidative phosphorylation in NTERA2 cells and induced neuritic differentiation in SH-SY5Y cells. This downregulation also produced a strong DNA damage response (DDR) and an increased apoptotic signature by RNAseq analysis, and decreased proliferation in both cell lines. It also decreased radiosensitivity in NTERA2 cells but not in SH-SY5Y. Conclusions: These results suggest that MDL1AS reduction can modulate radiosensitivity, metabolism, and differentiation in a cell type-specific manner. Furthermore, MDL1AS may constitute a predictive biomarker and a molecular target for new therapies. Full article

Leptobotia rotundilobus is a newly described species in the subfamily Leptobotinae (Teleostei: Cypriniformes), which is endemic to China. Research on this recently discovered species is preliminary, characterized by limited baseline data and the absence of a fully sequenced mitochondrial genome. To elucidate the structural features of the mitochondrial genome of L. rotundilobus, we performed whole-genome sequencing using next-generation sequencing technology and analyzed its genomic composition, gene content, and structural variation through genome assembly and bioinformatics. The complete circular sequence, spanning 16,593 bp, comprises 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a typical control region (D-loop), all arranged in the canonical order. The overall base composition of the genome was determined to be 30.8% adenine (A), 24.4% thymine (T), 28.6% cytosine (C), and 16.2% guanine (G). This A+T bias (55.2%) is consistent with the mitochondrial genomes of other Leptobotia, which may affect secondary structure. The ratio of non-synonymous (Ka) to synonymous substitutions (Ks) of 13 PCGs of 16 Leptobotinae species is far less than 1 (0.012–0.063), indicating strong negative or purifying selection on the mitogenome in these species. Moreover, to investigate the phylogenetic relationships within the subfamily Leptobotinae, particularly within the genus Leptobotia, we constructed multiple phylogenetic trees of the mitogenome and concatenated 13 PCGs of 39 sequences with Sinibotia superciliaris as an outgroup. The phylogentic trees using the maximum likelihood (ML) and Bayesian inference (BI) methods consistently indicate that: (1) after correcting the species identification error, L. rotundilobus is closely related to L. micra; and (2) the species of Leptobotia and Parabotia each form a monophyletic group. This study provides new insights into the taxonomy and phylogenetic relationships of Leptobotinae, with a particular focus on the genus Leptobotia, thereby contributing to the clarification of the systematics, origin, and evolution of Botiidae. Full article

Delayed effects of acute radiation exposure (DEARE), including radiation pneumonitis (lung-DEARE), develop weeks to months after radiation exposure. Pathway-targeted biomarkers that capture early oxidative stress and cell death could improve risk stratification and provide objective measures of mitigator efficacy. The objective was to test whether molecular lung imaging predicts long-term survival and mitigator response after irradiation. Rats received 13.5 Gy leg-out partial-body irradiation with a subset treated with the radiation-injury mitigator lisinopril. Rats underwent lung imaging at weeks 2 and 4 post-irradiation with ^99mTc-duramycin (cell death) and ^99mTc-HMPAO (oxidative stress). Plasma mitochondrial damage-associated molecular patterns (mtDAMPs) were also measured. Irradiation reduced survival with animals evidencing significant pleural effusion as an indication of radiation pneumonitis, which was mitigated with lisinopril as previously shown. Lung uptake of both imaging biomarkers increased in irradiated rats between weeks 2 and 4, consistent with worsening cell death and oxidative stress. Rats that succumbed by day 120 exhibited significantly larger increases in both biomarkers than the survivors. A predictive test was developed that predicted death by day 120 with ~70% sensitivity and specificity. Plasma mtDAMPs (ND1/2 and ATPase 6/8) increased following irradiation, and the D-loop increase from week 2 to 3 separated outcomes (increase in nonsurvivors versus decrease in survivors). Both imaging and mtDAMPs data from lisinopril-treated animals showed blunted responses. Early dual-tracer molecular lung imaging predicted long-term survival after radiation exposure and tracked mitigation with lisinopril. Circulating mtDAMPs may provide complementary systemic information to further strengthen early risk stratification after radiation exposure. Full article

There is accumulating evidence that distinct mitochondrial DNA (mtDNA) methylation and hydroxymethylation patterns exist in Parkinson’s disease (PD). However, most studies have been limited to the investigation of specific target regions, rather than the entire mtDNA, and have been further hindered by other methodological discrepancies and the lack of non-CpG context investigation. Here, we provide a comprehensive profile of methylation and hydroxymethylation levels across the mitochondrial genome, at global and single-base resolution, in CpG and non-CpG (CHG, CHH) contexts in blood samples from early-onset PD (EOPD) patients (n = 39) and age- and sex-matched controls (n = 63). Bisulfite (BS) and oxidative-bisulfite (oxBS) conversions in parallel workflows followed by next-generation sequencing (NGS) using Illumina’s Novaseq 6000 sequencing system identified mitochondrial 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in all contexts. Global mtDNA methylation was significantly higher in EOPD patients vs. matched controls in the CpG context (p = 5.63 × 10⁻³) in the BS status, and in all contexts [CpG (p = 2.67 × 10⁻⁴), CHG (p = 0.015), CHH (p = 0.012)] in the oxBS status, i.e., “true methylation”. At single-base resolution, the most statistically significant sites across the mitogenome, in the D-loop region, and CpG context, were primarily hypomethylated in EOPD patients compared to matched controls. Upon further validation, both global and base resolution mtDNA (hydroxy)methylation results could act as blood-based biomarkers for EOPD. Full article

Alzheimer’s disease (AD), the leading cause of dementia, is expected to markedly increase in prevalence in the coming decades. Beyond amyloid and tau pathologies, accumulating evidence suggests that mitochondrial dysfunction and impaired protein homeostasis play crucial roles in AD onset and progression. Building on our previous identification of molecular signatures associated with disease progression, this study investigated whether epigenetic alterations of mitochondrial DNA (mtDNA) contribute to cognitive decline. Specifically, we analyzed the methylation status of the mtDNA regulatory D-loop region and mtDNA copy number in blood-derived DNA samples from 75 participants who we followed longitudinally over eight years. Subjects were classified into four groups according to clinical progression from healthy cognition to mild cognitive impairment (MCI) and AD. Using a linear mixed-effects model, we observed significant differences in methylation dynamics and mtDNA copy number across groups and time points. Healthy controls showed a progressive increase in D-loop methylation, whereas individuals converting to AD exhibited a marked decrease in its level. An opposite trend was evidenced for mtDNA copy number. These findings suggest that reduced D-loop methylation and increased mtDNA are associated with mitochondrial dysfunction and disease progression, whereas increased methylation may represent a possible protective mechanism. Full article

Sphaerodactylidae play a crucial role in ecosystems, possessing significant ecological, scientific, and conservation value. They contribute to pest control and the maintenance of ecological balance, and also provide abundant materials for research in evolutionary biology and biodiversity. To refine the phylogenetic position of Teratoscincus scincus within the Sphaerodactylidae using mitogenomic data, this study sequenced the complete mitochondrial genome of T. scincus using the Illumina NovaSeq Xplus platform, and subsequently performed assembly, annotation, and analysis. The phylogenetic relationships of T. scincus within the Sphaerodactylidae were analyzed using 13 protein-coding genes (PCGs) from the mitochondrial genome via Bayesian inference (BI) and maximum likelihood (ML) methods. The complete mitochondrial genome of T. scincus is 16,943 bp in length and consists of 13 PCGs, 22 tRNA genes, 2 rRNA genes, and 1 control region (D-loop). The base composition shows a distinct AT preference, with the highest A + T content (56.3%) found in the PCGs region. A phylogenetic tree was constructed based on the amino acid sequences of 13 PCGs from the mitochondrial genomes of nine Sphaerodactylidae species retrieved from GenBank and the newly sequenced T. scincus generated in this study. The results confirm that T. scincus belongs to the genus Teratoscincus within the family Sphaerodactylidae. Phylogenetic analysis reveals that T. scincus and Teratoscincus keyserlingii cluster into a monophyletic group, suggesting a close phylogenetic relationship. Additionally, the phylogenetic tree provides new molecular evidence for understanding the formation mechanism of Sphaerodactylidae diversity. This study not only enriches the mitochondrial genome database of Sphaerodactylidae but also lays an important foundation for subsequent research on the adaptive evolution and conservation biology of T. scincus. Full article

This study presents an in silico proof of concept exploring whether deep learning models can perform conditional mitochondrial DNA (mtDNA) sequence prediction across species boundaries. A CNN–BiLSTM model was trained under a leave-one-species-out (LOSO) scheme on complete mitochondrial genomes from 21 vertebrate species, primarily archosaurs. Model behavior was evaluated through multiple complementary tests. Under context-conditioned settings, the model performed next-nucleotide prediction using overlapping 200 bp windows to assemble contiguous 2000 bp fragments for held-out species; the resulting high token-level accuracy (>99%) under teacher forcing is reported as a diagnostic of conditional modeling capacity. To assess leakage-free performance, a two-flank masked-span imputation task was conducted as the primary evaluation, requiring free-running reconstruction of 500 bp interior spans using only distal flanking context; in this setting, the model consistently outperformed nearest-neighbor and demonstrated competitive performance relative to flank-copy baselines. Additional robustness analyses examined sensitivity to window placement, genomic region (coding versus D-loop), and random initialization. Biological plausibility was further assessed by comparing predicted fragments to reconstructed ancestral sequences and against composition-matched null models, where observed identities significantly exceeded null expectations. Using the National Center for Biotechnology Information (NCBI) BLAST web interface, BLASTn species identification was performed solely as a biological plausibility check, recovering the correct species as the top hit in all cases. Although limited by dataset size and the absence of ancient DNA damage modeling, these results demonstrate the feasibility of conditional mtDNA sequence prediction as an initial step toward more advanced generative and evolutionary modeling frameworks. Full article

Manipulating the mitochondrial genome remains a significant challenge in genetic engineering, primarily due to the mitochondrial double-membrane structure. While recent advances have expanded the genetic toolkit for nuclear and cytoplasmic targets, precise editing of mitochondrial DNA (mtDNA) has remained elusive. Here we report the first successful mitochondrial import of a catalytically active RNA-guided prokaryotic Argonaute protein from the mesophilic bacterium Alteromonas macleodii (AmAgo). By guiding AmAgo to the single-stranded D- or R-loop region of mtDNA using synthetic RNA guides, we observed a nearly threefold reduction in mtDNA copy number in human cell lines. This proof of concept study demonstrates that a bacterial Argonaute can remain active within the mitochondrial environment and influence mtDNA levels. These findings establish a foundational framework for further development of programmable systems for mitochondrial genome manipulation. Full article

The growing demand for robust food authentication methods has driven the establishment of fast, sensitive, and field-based detection systems for identifying meat species. This study presents a colorimetric-based PSR approach for identifying yak (Bos grunniens) meat within fresh, thermally processed, and blended meat samples. Targeting the mitochondrial D-loop locus, the assay incorporates a simple alkaline lysis (AL) procedure for efficient DNA extraction, eliminating the requirement for specialized instrumentation. The PSR assay demonstrated high specificity, showing no evidence of cross-reactivity with closely associated food animals such as buffalo, cattle, goat, sheep, mithun, and pig. Sensitivity assessment revealed the assay’s capability to detect 1 pg of yak DNA, with reliable performance in samples exposed to thermal conditions up to 121 °C. Additionally, the technique detected yak meat down to a concentration of 0.1% in binary beef mixtures. This method provides a significant improvement in sensitivity over end-point PCR and is particularly well-suited for field applications due to its practical simplicity, affordability, as well as no reliance on sophisticated instrument. This is, to the best of our understanding, the first reported PSR-based approach developed for the identification of yak meat, offering a robust tool for food origin verification, regulatory enforcement, and product integrity monitoring. Full article

Mitochondrial DNA (mtDNA) mutations are prevalent across cancer genomes, and growing evidence implicates their multifaceted role in energy metabolism with tumorigenesis. Ovarian cancer, in particular, demonstrates high mtDNA copy numbers and increased incidences of truncating and missense mtDNA mutations, with heteroplasmy levels predictive of prognosis. This review provides a comprehensive description of published mtDNA sequencing data in ovarian cancer, the majority being high-grade serous samples, encompassing both coding and non-coding regions. MtDNA mutations within non-coding regions, such as the D-loop control region, can affect mtDNA replication and transcription, hence affecting overall mtDNA copy numbers, while mtDNA mutations within coding regions can directly impact respiratory complex function and downstream metabolic pathways. MtDNA mutations may serve as clinically valuable diagnostic biomarkers for ovarian cancer and predictors for chemoresistance. We also explore ongoing efforts to deepen our understanding of mitochondrial oncogenetics through the creation of novel cancer models enabled by mitochondrial gene editing techniques. Developing robust human ovarian cancer cell models will be critical to elucidate mechanistic and phenotypic consequences of mtDNA mutations, assess drug response and resistance and identify new therapeutic targets to advance precision oncology in this emerging field. Full article

Distant hybridization is key to trait innovation and speciation, with Cyprinidae hybrid phylogeny helping to clarify diversification mechanisms. Yet, a major gap persists in Cyprinidae studies: the stabilization mechanisms of interspecific distant hybrid lineages. To address this, we systematically analyzed the molecular phylogeny of seven Cyprinidae distant hybrid lineages and their parental species, using an integrative genetic framework encompassing four mitochondrial genes (Cytb, COI, 16S rRNA, D-loop) and five nuclear genes (EGR2b, IRBP2, RAG1, RAG2, RH2). Homologous sequences of 41 representative Cyprinidae species (85 samples) were retrieved from GenBank to supplement the dataset. Phylogenies were reconstructed from concatenated sequences, complemented by haplotype networks. Intra-/interspecific divergence was quantified using two mitochondrial genes (COI, Cytb) and two nuclear (RAG1, RH2). The results showed that these hybrid lineages exhibited variation patterns analogous to other Cyprinidae species. Both ML and BI trees reconstructed exhibited congruent topologies with high support (bootstrap/BPP > 80%), resolving genus/species-level relationships. While most hybrids clustered intermediately between their parental species, they typically displayed maternal affinity. A notable exception was the 2nNCRC (a homodiploid hybrid from Cyprinus carpio ♀ × Megalobrama amblycephala ♂), which displayed convergent evolution toward Carassius auratus. COI-based K2P genetic distance analysis revealed 2nNCRC had a much closer relationship with C. auratus (0.0119) than with its parents (0.1249 to C. carpio, 0.1552 to M. amblycephala). These nine genes elucidate the genetic relationships between Cyprinid hybrid lineages and progenitors, serving as pivotal molecular markers for parentage tracing and genetic dissection of distant hybridization mechanisms. The integrated mitochondrial–nuclear marker system in this study advances understanding of cytonuclear coadaptation and the stabilization of interspecific distant hybrid lineages in Cyprinidae. Specifically, it provides a precise tool for parentage tracing, Cyprinid germplasm conservation, and targeted regulation of hybrid breeding—laying a foundation for exploring hybrid speciation and developing elite aquaculture germplasms. Full article

The mitochondrial displacement loop (D-loop) region is a non-coding control region that plays a crucial role in replication and transcription, serving as an informative marker for evolutionary and demographic studies. In this study, the complete mitochondrial D-loop sequences from NCBI public database were analyzed across nine Indian and other dromedary populations. Evolutionary and pairwise sequence analysis indicate distinct separation from foreign populations and substantive clustering of Indian breeds within a monophyletic clade. Indian breeds showed greater than 99.4% sequence identity, minimal diversity (π ≈ 0.003), and limited divergence (k = 3–4), whereas Arabian and Iranian populations exhibited more prominent variability (π ≈ 0.004–0.0044; k ≈ 5). Nucleotide composition analyses corroborated the AT-rich nature of the D-loop with conserved sequence length and enrichment of CpG motifs. This suggests selective conservation of functional elements in the D-loop sequence region. Correlation and correspondence analyses highlighted non-random nucleotide usage and repeat dynamics consistent with replication-associated mutational pressures. Demographic structural diversity showed that nearly all genetic variation was distributed among populations (~99.9%), with minimal variation within breeds. Pairwise differentiation values indicated substantial divergence between Indian and foreign breeds, with Indian desert breeds displaying restricted differentiation, possibly due to shared maternal ancestry. Neutrality test results for the sequence dataset interpreted ongoing demographic expansion or bottleneck recovery for the Arabian, Iranian, Sindhi, and Kharai populations. In contrast, for other Indian desert breeds, the neutrality test values that were closing towards zero may express current population shrinkage. Conserved transcription factor binding motifs further support the role of purifying selection on sequence functional constraints. These findings highlight that Indian dromedaries bear highly conserved mitochondrial D-loop sequences, which are influenced by purifying selection and demographic stability. This low mitochondrial diversity in non-coding sequence can mirror the declining population size and emphasizes the urgent need for targeted conservation strategies. Full article

As a contribution to our understanding of postglacial colonisation history of Anatolia, the Caucasus and the Middle East, we increased the existing phylogeographic coverage of the widespread Balkan short-tailed mouse Mus macedonicus. This added 92 new mitochondrial D-loop sequences (73 new haplotypes) from Anatolia and Thrace to generate a total dataset for the species of 221 sequences (174 haplotypes). We confirmed the previously described existence of a northern lineage (Anatolia, the southern Balkans, the Caucasus, Iran and Syria) and southern lineage (Israel and Lebanon) and generated Bayesian Skyline Plots to show demographic expansion after the Last Glacial Maximum (LGM) in the northern lineage but not the southern. We used haplotype networks to reveal haplotypes close to the ancestral condition of the northern lineage and to infer spread through its range, including colonisation of the southern Balkans. Our various phylogenetic reconstructions also show finer-scale geographic structuring. M. macedonicus likely occupied two separate glacial refugia in the vicinities of Israel and Lebanon (southern lineage) and Anatolia, Georgia and Iran (northern lineage) although further work is needed for precise localisation. M. macedonicus has become a well-worked model system for the phylogeography of a region deserving more attention. Full article

Sheep play a central role in Kazakhstan’s pastoral economy, yet the maternal genetic composition of its traditional breeds remains poorly characterized. We analyzed partial mitochondrial D-loop sequences (848 bp) from 115 individuals of three fat-tailed coarse-wooled breeds (Edilbay, Kazakh fat-tailed coarse-wooled, and Gissar) to assess genetic diversity, population structure, and phylogenetic relationships. Ninety-eight haplotypes were identified, indicating high haplotype diversity (Hd = 0.996 ± 0.002) and moderate nucleotide diversity (π = 0.02624 ± 0.00048). Haplotypes clustered into haplogroups A (57.4%) and B (42.6%), with Edilbay dominating the star-like cluster of haplogroup A, consistent with recent expansion. AMOVA revealed that most variation (92.03%) occurred within populations, with no significant differentiation among breeds. Phylogenetic analyses placed Edilbay close to the most recent common ancestor of fat-tailed domestic sheep and the wild Ovis species, suggesting retention of an ancestral lineage. These findings highlight Kazakhstan as a genetic crossroads in sheep history and underscore the conservation value of its maternal diversity. Full article