RESUMO
Pancreatic cancer is one of the leading causes of cancer-associated mortality, with a poor treatment approach. Previous study has shown that inducing pyroptosis in pancreatic ductal adenocarcinoma (PDAC) slows the growth of PDACs, implying that pyroptosis inducers are potentially effective for PDAC therapy. Here, we found that Dronedarone hydrochloride (DH), an antiarrhythmic drug, induces pyroptosis in pancreatic cancer cells and inhibits PDAC development in mice. In PANC-1 cells, DH caused cell death in a dosage- and time-dependent manner, with only pyroptosis inhibitors and GSDMD silencing rescuing the cell death, indicating that DH triggered GSDMD-dependent pyroptosis. Further work revealed that DH increased mitochondrial stresses and caused mitochondrial DNA (mtDNA) leakage, activating the cytosolic STING-cGAS and pyroptosis pathways. Finally, we assessed the anti-cancer effects of DH in a pancreatic cancer mouse model and found that DH treatment suppressed pancreatic tumor development in vivo. Collectively, our investigation demonstrates that DH triggers pyroptosis in PDAC and proposes its potential effects on anti-PDAC growth.
Assuntos
DNA Mitocondrial , Dronedarona , Neoplasias Pancreáticas , Piroptose , Piroptose/efeitos dos fármacos , Animais , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/genética , Humanos , Dronedarona/farmacologia , DNA Mitocondrial/metabolismo , DNA Mitocondrial/genética , Camundongos , Linhagem Celular Tumoral , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/genética , Camundongos NusRESUMO
Oocytes play a crucial role in transmitting maternal mitochondrial DNA (mtDNA), essential for the continuation of species. However, the effects of mitochondrial reactive oxygen species (ROS) on mammalian oocyte maturation and mtDNA maintenance remain unclear. We investigated this by conditionally knocking out the Sod2 gene in primordial follicles, elevating mitochondrial matrix ROS levels from early oocyte stages. Our data indicates that reproductive aging in Sod2 conditional knockout females begins at 6 months, with oxidative stress impairing oocyte quality, particularly affecting OXPHOS complex II and mtDNA-encoded mRNA levels. Despite unchanged mtDNA mutation load, mtDNA copy numbers exhibited significant variations. Strikingly, reducing mtDNA copy numbers by reducing mtSSB protein, crucial for mtDNA replication, accelerated reproductive aging onset to three months, underscoring the critical role of mtDNA copy number maintenance under oxidative stress conditions. This research provides new insights into the relationship among mitochondrial ROS, mtDNA, and reproductive aging, offering potential strategies for delaying aging-related fertility decline.
Assuntos
Envelhecimento , DNA Mitocondrial , Oócitos , Espécies Reativas de Oxigênio , Animais , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Oócitos/metabolismo , Feminino , Espécies Reativas de Oxigênio/metabolismo , Envelhecimento/genética , Camundongos , Reprodução/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Estresse Oxidativo , Camundongos Knockout , Variações do Número de Cópias de DNA , Mitocôndrias/metabolismo , Mitocôndrias/genéticaRESUMO
KEY MESSAGE: We report the mitochondrial genome of 39 diploid potatoes and identify a candidate ORF potentially linked to cytoplasmic male sterility in potatoes. Potato (Solanum tuberosum L.) holds a critical position as the foremost non-grain food crop, playing a pivotal role in ensuring global food security. Diploid potatoes constitute a vital genetic resource pool, harboring the potential to revolutionize modern potato breeding. Nevertheless, diploid potatoes are relatively understudied, and mitochondrial DNA can provide valuable insights into key potato breeding traits such as CMS. In this study, we examine and assemble the mitochondrial genome evolution and diversity of 39 accessions of diploid potatoes using high-fidelity (HiFi) sequencing. We annotated 54 genes for all the investigated accessions, comprising 34 protein-coding genes, 3 rRNA genes, and 17 tRNA genes. Our analyses revealed differences in repeats sequences between wild and cultivated landraces. To understand the evolution of diploid maternal lineage inheritance, we conducted phylogenetic analysis, which clearly distinguished mitochondrial from nuclear gene trees, further supporting the evidence-based of clustering between wild and cultivated landraces accessions. Our study discovers new candidate ORFs associated with CMS in potatoes, including ORF137, which is homologous to other CMS in Solanaceae. Ultimately, this work bridges the gap in mitochondrial genome research for diploid potatoes, providing a steppingstone into evolutionary studies and potato breeding.
Assuntos
Diploide , Genoma Mitocondrial , Filogenia , Solanum tuberosum , Solanum tuberosum/genética , Genoma Mitocondrial/genética , Genoma de Planta/genética , Fases de Leitura Aberta/genética , DNA Mitocondrial/genéticaRESUMO
Metabolic syndrome is a growing concern in developed societies and due to its polygenic nature, the genetic component is only slowly being elucidated. Common mitochondrial DNA sequence variants have been associated with symptoms of metabolic syndrome and may, therefore, be relevant players in the genetics of metabolic syndrome. We investigate the effect of mitochondrial sequence variation on the metabolic phenotype in conplastic rat strains with identical nuclear but unique mitochondrial genomes, challenged by high-fat diet. We find that the variation in mitochondrial rRNA sequence represents risk factor in the insulin resistance development, which is associated with diacylglycerols accumulation, induced by tissue-specific reduction of the oxidative capacity. These metabolic perturbations stem from the 12S rRNA sequence variation affecting mitochondrial ribosome assembly and translation. Our work demonstrates that physiological variation in mitochondrial rRNA might represent a relevant underlying factor in the progression of metabolic syndrome.
Assuntos
Haplótipos , Síndrome Metabólica , RNA Ribossômico , Síndrome Metabólica/genética , Síndrome Metabólica/metabolismo , Animais , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , Ratos , Masculino , RNA Mitocondrial/genética , RNA Mitocondrial/metabolismo , Predisposição Genética para Doença , Resistência à Insulina/genética , Dieta Hiperlipídica/efeitos adversos , Mitocôndrias/metabolismo , Mitocôndrias/genética , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismoRESUMO
Heteroplasmic mitochondrial DNA (mtDNA) variants accumulate as humans age, particularly in the stem-cell compartments, and are an important contributor to age-related disease. Mitochondrial dysfunction has been observed in osteoporosis and somatic mtDNA pathogenic variants have been observed in animal models of osteoporosis. However, this has never been assessed in the relevant human tissue. Mesenchymal stem cells (MSCs) are the progenitors to many cells of the musculoskeletal system and are critical to skeletal tissues and bone vitality. Investigating mtDNA in MSCs could provide novel insights into the role of mitochondrial dysfunction in osteoporosis. To determine if this is possible, we investigated the landscape of somatic mtDNA variation in MSCs through a combination of fluorescence-activated cell sorting and single-cell next-generation sequencing. Our data show that somatic heteroplasmic variants are present in individual patient-derived MSCs, can reach high heteroplasmic fractions and have the potential to be pathogenic. The identification of somatic heteroplasmic variants in MSCs of patients highlights the potential for mitochondrial dysfunction to contribute to the pathogenesis of osteoporosis.
Assuntos
DNA Mitocondrial , Células-Tronco Mesenquimais , Humanos , Células-Tronco Mesenquimais/metabolismo , DNA Mitocondrial/genética , Osteoporose/genética , Osteoporose/patologia , Osteoporose/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/genética , Análise de Célula Única , Sequenciamento de Nucleotídeos em Larga Escala , Feminino , Heteroplasmia/genética , Masculino , Citometria de Fluxo , Variação Genética , Pessoa de Meia-IdadeRESUMO
Cells possess multiple mitochondrial DNA (mtDNA) copies, which undergo semi-autonomous replication and stochastic inheritance. This enables mutant mtDNA variants to arise and selfishly compete with cooperative (wildtype) mtDNA. Selfish mitochondrial genomes are subject to selection at different levels: they compete against wildtype mtDNA directly within hosts and indirectly through organism-level selection. However, determining the relative contributions of selection at different levels has proven challenging. We overcome this challenge by combining mathematical modeling with experiments designed to isolate the levels of selection. Applying this approach to many selfish mitochondrial genotypes in Caenorhabditis elegans reveals an unexpected diversity of evolutionary mechanisms. Some mutant genomes persist at high frequency for many generations, despite a host fitness cost, by aggressively outcompeting cooperative genomes within hosts. Conversely, some mutant genomes persist by evading inter-organismal selection. Strikingly, the mutant genomes vary dramatically in their susceptibility to genetic drift. Although different mechanisms can cause high frequency of selfish mtDNA, we show how they give rise to characteristically different distributions of mutant frequency among individuals. Given that heteroplasmic frequency represents a key determinant of phenotypic severity, this work outlines an evolutionary theoretic framework for predicting the distribution of phenotypic consequences among individuals carrying a selfish mitochondrial genome.
Assuntos
Caenorhabditis elegans , DNA Mitocondrial , Evolução Molecular , Genoma Mitocondrial , Mutação , Animais , Caenorhabditis elegans/genética , DNA Mitocondrial/genética , Seleção Genética , Deriva Genética , Modelos Genéticos , Mitocôndrias/genética , Mitocôndrias/metabolismo , GenótipoRESUMO
This study presents the first mitochondrial DNA analysis of native cattle in Kyrgyzstan, examining sequences from the D-loop region of 20 Kyrgyz native cattle. A phylogenetic tree was constructed to estimate the genetic diversity and lineages, revealing two major haplogroups (T and I). Regional analysis showed a significant frequency difference (p < 0.05) between these haplogroups: Haplogroup I was found to be more prevalent (0.556) in the lower elevation areas (elevation ~1000 m) and less prevalent (0.100) in the higher elevations (elevation ~2500 to 3000 m), suggesting that environmental factors influence genetic distribution among Kyrgyz cattle. Three sub-haplogroups T2, T3, and T4 were observed within major haplogroup T, whereas only one sub-haplogroup (I1) was observed in this study. We also compared the distribution patterns of haplogroups T and I in Kyrgyz with those of some areas in Asia previously reported and found that in Central and Northeast Asia, haplogroup T was dominant, but the gene flow of haplogroup I was also present. The results of this study underscore the importance of regional environmental factors, including altitude, in shaping the genetic structure of livestock populations and would be useful to understand the historical movements and adaptations of Kyrgyz native cattle.
Assuntos
DNA Mitocondrial , Variação Genética , Haplótipos , Filogeografia , Animais , Bovinos/genética , Quirguistão , DNA Mitocondrial/genética , Altitude , Feminino , Filogenia , Fluxo Gênico , Herança Materna/genéticaRESUMO
The type species of the genus Halipegus Looss, 1899, Halipegus ovocaudatus (Vulpian, 1859) is a generalist parasite of different species of amphibians, mainly anurans. To date, the phylogenetic position of this species has not been established. Specimens of H. ovocaudatus, were collected from three species of water frogs, Pelophylax ridibundus (Pallas), P. esculentus (Linnaeus), and P. lessonae (Camerano) inhabiting the Middle Volga region (European Russia). In our study, we provide detailed morphological redescription of these digeneans and combine it with molecular phylogenetic analyses based on partial sequences of the 28S rDNA and coI mtDNA genes. The phylogenetic position of H. ovocaudatus among the derogenids has been established as a sister clade to other representatives of the Halipeginae. We compared pairwise distances based on partial sequences of coI mtDNA genes of H. ovocaudatus and other representatives of Derogenidae. It was shown, that adults of H. ovocaudatus from different hosts are representatives of the same species. Specimens parasitizing three frog hosts from several localities differ slightly in body shape and size, which probably reflects host-induced intraspecific variability.
Assuntos
Filogenia , Especificidade da Espécie , Trematódeos , Animais , Trematódeos/classificação , Trematódeos/genética , Trematódeos/anatomia & histologia , RNA Ribossômico 28S/genética , Federação Russa , Ranidae/parasitologia , DNA Mitocondrial/genética , Anuros/parasitologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , DNA de Helmintos/genéticaRESUMO
The round goby, Neogobius melanostomus, is a successful invasive fish species. Originating from the Caspian and Black Sea, it is now distributed widely within European fresh- and brackish waters. The River Rhine was colonized in 2008 only a few years after the opening of the Rhine-Main-Danube canal and only four years after N. melanostomus was first reported in the upper Danube River. Its invasion history of the River Rhine was unclear because the species was first detected close to the Rhine river delta which would suggest a route of invasion other than via the Rhine-Main-Danube canal. To investigate the colonization history of N. melanostomus in the Rhine, we combined abundance estimates with molecular analysis. Abundance estimates found N. melanostomus to be dominant in the Lower Rhine (> 90% of all catches). Molecular analysis was done on 286 individuals from four different sites. Using the mitochondrial control region (d-loop), we found three different haplotypes in both Rhine sites. None of the potential invasive source populations in the rivers Danube and Trave exhibited all three haplotypes. The molecular data therefore supported a scenario of two different colonization directions. Our results show that the invasion history of the River Rhine is complex and warrants further investigation.
Assuntos
Haplótipos , Espécies Introduzidas , Perciformes , Rios , Animais , Perciformes/genética , Genética Populacional , DNA Mitocondrial/genéticaRESUMO
BACKGROUND: Tiarella polyphylla D. Don has been traditionally used to cure asthma and skin eruptions. However, the sequence and the structure of the mitogenome of T. polyphylla remained elusive, limiting the genomic and evolution analysis based on the mitogenome. RESULTS: Using a combination of Illumina and Nanopore sequencing reads, we de novo assembled the complete mitogenome of T. polyphylla. In addition to unveiling the major configuration of the T. polyphylla mitogenome was three circular chromosomes with lengths of 430,435 bp, 126,943 bp, and 55,269 bp, we revealed five (R01-R05) and one (R06) repetitive sequence could mediate the intra- and inter-chromosomal recombination, respectively. Furthermore, we identified 208 short and 25 long tandem segments, seven cp-derived mtDNAs, 106 segments of mtDNAs transferred to the nuclear genome, and 653 predicted RNA editing sites. Based on the sequence of the mitogenomes, we obtained the resolved phylogeny of the seven Saxifragales species. CONCLUSIONS: These results presented the mitogenome features and expanded its potential applications in phylogenetics, species identification, and cytoplasmic male sterility (CMS) in the future.
Assuntos
Genoma Mitocondrial , Filogenia , DNA Mitocondrial/genética , Cromossomos de Plantas/genética , Edição de RNARESUMO
Currently, the molecular background based on mitochondrial DNA (mtDNA) analysis of canine testicular tumours is underestimated. The available data mostly focus on histopathological evaluations, with a few reports of nuclear genome (nDNA) studies. Tumourigenesis represents a highly complex and diverse genetic disorder, which can also encompass defects in mtDNA. The aim of this study was to identify molecular changes in whole mitochondrial genome sequences obtained from dogs affected by testicular tumours. Samples of blood, tumour, and healthy tissue were collected from each animal, and mtDNA (ultimately 45 samples) was subsequently sequenced. Thereafter, protein analyses were performed to assess the impact of the identified molecular alterations on the amino acid level. The total number of observed changes included 722 SNPs, 12 mutations, 62 indels, 5 indel mutations, and 35 heteroplasmic sites. The highest number of mtDNA variants in protein-coding genes COX1, COX3, ATP6, ND1, ND4, and ND5 was observed. Interestingly, SNPs were found in 10 out of 22 tRNA genes. Most of the identified mtDNA defects were synonymous changes at the amino acid level. Also, polymorphisms and heteroplasmy were frequently observed in the variable number of tandem repeat (VNTR) regions, especially in its fragment spanning 16,138-16,358 bp. Based on the obtained results, it was possible to select 11 polymorphisms that occurred in all the tested samples (benign, malignant) and an additional five SNPs identified only in benign neoplasms. The comprehensive analysis of malignant testicular tumours demonstrated a significant diversity in their molecular profiles, with changes ranging from 17 to 101 per sample.
Assuntos
DNA Mitocondrial , Doenças do Cão , Genoma Mitocondrial , Polimorfismo de Nucleotídeo Único , Neoplasias Testiculares , Sequenciamento Completo do Genoma , Animais , Masculino , Cães , Neoplasias Testiculares/genética , Neoplasias Testiculares/veterinária , Neoplasias Testiculares/patologia , Doenças do Cão/genética , DNA Mitocondrial/genética , Sequenciamento Completo do Genoma/métodos , MutaçãoRESUMO
This survey reviews modern ideas on the structure and functions of mitochondrial and cytosolic aconitase isoenzymes in eukaryotes. Cumulative experimental evidence about mitochondrial aconitases (Aco2) as one of the main targets of reactive oxygen and nitrogen species is generalized. The important role of Aco2 in maintenance of homeostasis of the intracellular iron pool and maintenance of the mitochondrial DNA is discussed. The role of Aco2 in the pathogenesis of some neurodegenerative diseases is highlighted. Inactivation or dysfunction of Aco2 as well as mutations found in the ACO2 gene appear to be significant factors in the development and promotion of various types of neurodegenerative diseases. A restoration of efficient mitochondrial functioning as a source of energy for the cell by targeting Aco2 seems to be one of the promising therapeutic directions to minimize progressive neurodegenerative disorders.
Assuntos
Aconitato Hidratase , Mitocôndrias , Doenças Neurodegenerativas , Humanos , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/enzimologia , Doenças Neurodegenerativas/patologia , Aconitato Hidratase/metabolismo , Aconitato Hidratase/genética , Mitocôndrias/metabolismo , Mitocôndrias/genética , Animais , Espécies Reativas de Oxigênio/metabolismo , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , MutaçãoRESUMO
BACKGROUND: Coal-burning fluorosis is a chronic poisoning resulting from the prolonged use of locally available high-fluoride coal for heating and cooking. Prolonged fluoride exposure has been demonstrated to decrease PPARGC1A levels. Therefore, this case-control aims to evaluate the genetic association of PPARGC1A gene polymorphisms and methylation of the mitochondrial D-loop region with coal-burning fluorosis. RESULT: The results showed that the TT genotype at rs13131226 and the AA genotype at rs1873532 increased the risk of coal-burning fluorosis (OR = 1.84, P = 0.004; OR = 1.97, P = 0.007), the CT and CC genotypes at rs7665116 decreased the risk of coal-burning fluorosis (OR = 0.54, P = 0.003). The TT genotype at the rs2970847 site and the AA genotype at the rs2970870 site increase the risk of developing skeletal fluorosis (OR = 4.12, P = 0.003; OR = 2.22, P = 0.011). Haplotype AG constructed by rs3736265-rs1873532 increased the risk of the prevalence of coal-burning fluorosis (OR = 1.465, P = 0.005); CG decreased the risk of the prevalence of coal-burning fluorosis (OR = 0.726, P = 0.020). Haplotype CGGT constructed by rs6821591-rs768695-rs3736265-rs2970847 increased the risk of the prevalence of skeletal fluorosis (OR = 1.558, P = 0.027). A 1% increase in CpG_4 methylation levels in the mtDNA D-loop region is associated with a 2.3% increase in the risk of coal-burning fluorosis. Additionally. There was a significant interaction between rs13131226 and rs1873532; CpG_4 and CpG_8.9; rs13131224,rs6821591 and rs7665116 were observed in the occurrence of fluorosis in the Guizhou population (χ2 = 16.917, P < 0.001; χ2 = 21.198, P < 0.001; χ2 = 36.078, P < 0.001). CONCLUSION: PPARGC1A polymorphisms rs13131226 and rs1873532 and the mitochondrial DNA D-loop methylation site CpG_4 have been associated with an increased risk of fluorosis, conversely polymorphism rs7665116 was associated with a decreased risk of fluorosis. Polymorphisms rs2970870 were associated with increased risk of skeletal fluorosis, and polymorphism rs2970847 was associated with decreased risk of skeletal fluorosis. These SNPs and CpG can be used as potential targets to assess fluorosis risk.
Assuntos
Metilação de DNA , DNA Mitocondrial , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Polimorfismo de Nucleotídeo Único , Humanos , Estudos de Casos e Controles , Masculino , DNA Mitocondrial/genética , Feminino , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Pessoa de Meia-Idade , Adulto , Predisposição Genética para Doença , Carvão Mineral/efeitos adversos , Haplótipos , Genótipo , Antracose/genética , Estudos de Associação GenéticaRESUMO
BACKGROUND: The integration of nuclear mitochondrial DNA (mtDNA) into the mammalian genomes is an ongoing, yet rare evolutionary process that produces nuclear sequences of mitochondrial origin (NUMT). In this study, we identified and analysed NUMT inserted into the pig (Sus scrofa) genome and in the genomes of a few other Suinae species. First, we constructed a comparative distribution map of NUMT in the Sscrofa11.1 reference genome and in 22 other assembled S. scrofa genomes (from Asian and European pig breeds and populations), as well as the assembled genomes of the Visayan warty pig (Sus cebifrons) and warthog (Phacochoerus africanus). We then analysed a total of 485 whole genome sequencing datasets, from different breeds, populations, or Sus species, to discover polymorphic NUMT (inserted/deleted in the pig genome). The insertion age was inferred based on the presence or absence of orthologous NUMT in the genomes of different species, taking into account their evolutionary divergence. Additionally, the age of the NUMT was calculated based on sequence degradation compared to the authentic mtDNA sequence. We also validated a selected set of representative NUMT via PCR amplification. RESULTS: We have constructed an atlas of 418 NUMT regions, 70 of which were not present in any assembled genomes. We identified ancient NUMT regions (older than 55 million years ago, Mya) and NUMT that appeared at different time points along the Suinae evolutionary lineage. We identified very recent polymorphic NUMT (private to S. scrofa, with < 1 Mya), and more ancient polymorphic NUMT (3.5-10 Mya) present in various Sus species. These latest polymorphic NUMT regions, which segregate in European and Asian pig breeds and populations, are likely the results of interspecies admixture within the Sus genus. CONCLUSIONS: This study provided a first comprehensive analysis of NUMT present in the Sus scrofa genome, comparing them to NUMT found in other species within the order Cetartiodactyla. The NUMT-based evolutionary window that we reconstructed from NUMT integration ages could be useful to better understand the micro-evolutionary events that shaped the modern pig genome and enriched the genetic diversity of this species.
Assuntos
DNA Mitocondrial , Animais , DNA Mitocondrial/genética , Sus scrofa/genética , Genoma , Núcleo Celular/genética , Evolução Molecular , Filogenia , Suínos/genéticaRESUMO
BACKGROUND: Cascade testing can offer improved surveillance and timely introduction of clinical management for the at-risk biological relatives. Data on cascade testing and costs in mitochondrial diseases are lacking. To address this gap, we performed a cross-sectional retrospective study to provide a framework for cascade testing in mitochondrial diseases, to estimate the eligibility versus real-time uptake of cascade testing and to evaluate the cost of the genetic diagnosis of index cases and the cost of predictive cascade testing. METHODS: Data was collected through retrospective chart review. The variant inheritance pattern guided the identification of eligible first-degree relatives: (i) Males with mitochondrial DNA (mtDNA) single nucleotide variants (SNVs) - siblings and mothers. (ii) Females with mtDNA SNVs - siblings, mothers and offspring. (iii) Autosomal Dominant (AD) nuclear DNA (nDNA) variants - siblings, offspring and both parents. (iv) Autosomal Recessive (AR) nDNA variants - siblings. RESULTS: We recruited 99 participants from the Adult Mitochondrial Disease Clinic in Sydney. The uptake of cascade testing was 55.2% in the mtDNA group, 55.8% in the AD nDNA group and 0% in AR nDNA group. Of the relatives in mtDNA group who underwent cascade testing, 65.4% were symptomatic, 20.5% were oligosymptomatic and 14.1% were asymptomatic. The mean cost of cascade testing for eligible first-degree relatives (mtDNA group: $694.7; AD nDNA group: $899.1) was lower than the corresponding index case (mtDNA group: $4578.4; AD nDNA group: $5715.1) (p < 0.001). CONCLUSION: The demand for cascade testing in mitochondrial diseases varies according to the genotype and inheritance pattern. The real-time uptake of cascade testing can be influenced by multiple factors. Early diagnosis of at-risk biological relatives of index cases through cascade testing, confirms the diagnosis in those who are symptomatic and facilitates implementation of surveillance strategies and clinical care at an early stage of the disease.
Assuntos
DNA Mitocondrial , Testes Genéticos , Doenças Mitocondriais , Humanos , Doenças Mitocondriais/genética , Doenças Mitocondriais/diagnóstico , Estudos Transversais , Estudos Retrospectivos , Feminino , Masculino , Adulto , Pessoa de Meia-Idade , Testes Genéticos/métodos , DNA Mitocondrial/genética , IdosoRESUMO
Background: The Neotropics harbors the largest species richness of the planet; however, even in well-studied groups, there are potentially hundreds of species that lack a formal description, and likewise, many already described taxa are difficult to identify using morphology. Specifically in small mammals, complex morphological diagnoses have been facilitated by the use of molecular data, particularly from mitochondrial sequences, to obtain accurate species identifications. Obtaining mitochondrial markers implies the use of PCR and specific primers, which are largely absent for non-model organisms. Oxford Nanopore Technologies (ONT) is a new alternative for sequencing the entire mitochondrial genome without the need for specific primers. Only a limited number of studies have employed exclusively ONT long-reads to assemble mitochondrial genomes, and few studies have yet evaluated the usefulness of such reads in multiple non-model organisms. Methods: We implemented fieldwork to collect small mammals, including rodents, bats, and marsupials, in five localities in the northern extreme of the Cordillera Central of Colombia. DNA samples were sequenced using the MinION device and Flongle flow cells. Shotgun-sequenced data was used to reconstruct the mitochondrial genome of all the samples. In parallel, using a customized computational pipeline, species-level identifications were obtained based on sequencing raw reads (Whole Genome Sequencing). ONT-based identifications were corroborated using traditional morphological characters and phylogenetic analyses. Results: A total of 24 individuals from 18 species were collected, morphologically identified, and deposited in the biological collection of Universidad EAFIT. Our different computational pipelines were able to reconstruct mitochondrial genomes from exclusively ONT reads. We obtained three new mitochondrial genomes and eight new molecular mitochondrial sequences for six species. Our species identification pipeline was able to obtain accurate species identifications for up to 75% of the individuals in as little as 5 s. Finally, our phylogenetic analyses corroborated the identifications from our automated species identification pipeline and revealed important contributions to the knowledge of the diversity of Neotropical small mammals. Discussion: This study was able to evaluate different pipelines to reconstruct mitochondrial genomes from non-model organisms, using exclusively ONT reads, benchmarking these protocols on a multi-species dataset. The proposed methodology can be applied by non-expert taxonomists and has the potential to be implemented in real-time, without the need to euthanize the organisms and under field conditions. Therefore, it stands as a relevant tool to help increase the available data for non-model organisms, and the rate at which researchers can characterize life specially in highly biodiverse places as the Neotropics.
Assuntos
Genoma Mitocondrial , Mamíferos , Análise de Sequência de DNA , Animais , Mamíferos/genética , Genoma Mitocondrial/genética , Análise de Sequência de DNA/métodos , Nanoporos , Colômbia , DNA Mitocondrial/genética , Filogenia , Quirópteros/genética , Sequenciamento por Nanoporos/métodosRESUMO
Understanding the relationship between multi-scale processes driving community- and population-level diversity can guide conservation efforts. While the importance of population-level genetic diversity is widely recognized, it is not always assessed for conservation planning, and positive correlations with community-level diversity are sometimes assumed, such that only the latter is measured. We surveyed species richness and cumulative multispecies abundance of crayfishes in impounded and unimpounded streams in the southern Appalachian Mountains (Alabama, USA). We simultaneously assessed levels of population genetic diversity within two focal crayfishes (Faxonius validus and F. erichsonianus) using nuclear (nDNA; inter-simple sequence repeat (ISSR)) and mitochondrial DNA (mtDNA; mitochondrial DNA cytochrome oxidase subunit I (mtCOI)) markers. We then tested for species-genetic diversity correlations (SGDCs), species diversity-abundance correlations (i.e., more individuals hypothesis, MIH), and abundance-genetic diversity correlations (AGDCs) across sites. We also examined the relationship between each of the three different types of correlation (i.e., species richness, cumulative multispecies abundance, and population genetic diversity) and stream habitat characteristics and fragmentation. Surprisingly, based on F. validus mtDNA data, sites with the greatest multispecies abundance had the lowest genetic diversity, indicating a negative AGDC. However, no AGDC was evident from nDNA. There was no evidence of SGDCs for F. validus based on either of the two genetic data types. For F. erichsonianus, there was no evidence for SGDC or AGDC. When considering the community-level data only, there was no support for the MIH. Stream width was positively correlated with F. validus genetic diversity, but negatively correlated with multispecies abundance. Similarly, species richness was positively correlated with stream width in unimpounded streams but negatively correlated with width in impounded streams. These findings indicate that community-level diversity cannot be indiscriminately used as a proxy for population-level diversity without empirically testing this correlation on the focal group. As such, community- and population-level assessments for multiple crayfish species are needed to better understand drivers of diversity and eco-evolutionary processes which will aid in the conservation of this vulnerable taxonomic group.
Assuntos
Astacoidea , Biodiversidade , DNA Mitocondrial , Variação Genética , Rios , Animais , Astacoidea/genética , Variação Genética/genética , Alabama , DNA Mitocondrial/genética , Repetições de Microssatélites/genética , EcossistemaRESUMO
Persons living in industrial environments are exposed to levels of air pollution that can affect their health and fertility. The Czech capital city, Prague, and the Ostrava industrial agglomeration differ in their major sources of air pollution. In Prague, heavy traffic produces high levels of nitrogen oxides throughout the year. In the Ostrava region, an iron industry and local heating are sources of particulate matter (PM) and benzo[a]pyrene (B[a]P), especially in the winter. We evaluated the effects of air pollution on human sperm mitochondrial DNA (mtDNA). Using real-time PCR, we analysed sperm mtDNA copy number and deletion rate in Prague city policemen in two seasons (spring and autumn) and compared the results with those from Ostrava. In Prague, the sperm mtDNA deletion rate was significantly higher in autumn than in spring, which is the opposite of the results from Ostrava. The sperm mtDNA copy number did not show any seasonal differences in either of the cities; it was correlated negatively with sperm concentration, motility, and viability, and with sperm chromatin integrity (assessed with the Sperm Chromatin Structure Assay). The comparison between the two cities showed that the sperm mtDNA deletion rate in spring and the sperm mtDNA copy number in autumn were significantly lower in Prague vs. Ostrava. Our study supports the hypothesis that sperm mtDNA deletion rate is affected by the composition of air pollution. Sperm mtDNA abundance is closely associated with chromatin damage and standard semen characteristics.
Assuntos
Poluição do Ar , Variações do Número de Cópias de DNA , DNA Mitocondrial , Espermatozoides , Humanos , Masculino , DNA Mitocondrial/genética , Espermatozoides/efeitos dos fármacos , República Tcheca , Adulto , Poluição do Ar/efeitos adversos , Estações do Ano , Material Particulado/toxicidade , Material Particulado/efeitos adversos , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/efeitos adversos , Motilidade dos Espermatozoides/efeitos dos fármacos , PolíciaRESUMO
At the beginning of the 20th century, intense whaling activity took place in the South Shetland Islands, which is represented today in the form of ruins and numerous whale bones scattered along several Antarctic beaches. Despite being exposed to a harsh environment throughout the last decades, the present manuscript tried to answer if these bone remains still have viable DNA to allow species' identification using molecular methods. Several individuals were collected from the shores of Keller Peninsula, Admiralty Bay, Antarctica, and submitted to DNA extraction, amplification and Sanger sequencing. The challenging identification of these bone fragments proved to be still feasible. Mitochondrial DNA was successfully extracted, amplified and sequenced. A database with 43 sequences including previously published and newly determined sequences were built and enabled the precise identification to species level for some of the collected samples, therefore shedding light on the whales species that inhabited the region and how their overexploitation seems to have affected modern day presence of these species within the study area.
Assuntos
DNA Mitocondrial , Baleias , Animais , Regiões Antárticas , Baleias/classificação , Baleias/genética , DNA Mitocondrial/genética , Análise de Sequência de DNA , Reação em Cadeia da PolimeraseRESUMO
Primary mitochondrial diseases (PMDs) are a heterogeneous group of hereditary disorders characterized by an impairment of the mitochondrial respiratory chain. They are the most common group of genetic metabolic disorders, with a prevalence of 1 in 4,300 people. The presence of leukoencephalopathy is recognized as an important feature in many PMDs and can be a manifestation of mutations in both mitochondrial DNA (classic syndromes such as mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; myoclonic epilepsy with ragged-red fibers [RRFs]; Leigh syndrome; and Kearns-Sayre syndrome) and nuclear DNA (mutations in maintenance genes such as POLG, MPV17, and TYMP; Leigh syndrome; and mitochondrial aminoacyl-tRNA synthetase disorders). In this chapter, PMDs associated with white matter involvement are outlined, including details of clinical presentations, brain MRI features, and elements of differential diagnoses. The current approach to the diagnosis of PMDs and management strategies are also discussed. A PMD diagnosis in a subject with leukoencephalopathy should be considered in the presence of specific brain MRI features (for example, cyst-like lesions, bilateral basal ganglia lesions, and involvement of both cerebral hemispheres and cerebellum), in addition to a complex neurologic or multisystem disorder. Establishing a genetic diagnosis is crucial to ensure appropriate genetic counseling, multidisciplinary team input, and eligibility for clinical trials.