Transcriptional Regulation of 10 Mitochondrial Genes in Different Tissues of NCa CMS System in Brassica napus L. and Their Relationship with Sterility

Northern blot analysis was conducted with mitochondrial RNA from seedling leaves, floral buds, and developing seeds of NCa CMS, maintainer line and fertile F1 using ten mitochondrial genes as probes. The results revealed that 9 out of the 10 mitochondrial genes, except for atp6, showed no difference in different tissues of the corresponding materials of NCα CMS system and that they might be constitutively expressed genes. Eight genes, such as orf139, orf222, atpl, cox1, cox2, cob, rm5S, and rm26S, showed no difference among the three tissues of all the materials detected. So the expression of these eight genes was not regulated by nuclear genes and was not tissue-specific. The transcripts of atp9 were identical among different tissues, but diverse among different materials, indicating that transcription of atp9 was neither controlled by nuclear gene nor tissue-specific. Gene atp6 displayed similar transcripts with the same size among different tissues of all the materials but differed in abundance among tissues of corresponding materials and its expression might be tissue-specific under regulation of nuclear gene. Moreover, three transcripts of orf222 were detected in the floral buds of NCa cms and fertile F1, but no transcript was detected in floral buds of the maintainer line.The transcription of orf139 was similar to that of orf222 but only two transcripts of 0.8 kb and 0.6 kb were produced. The atp9 probe detected a single transcript of 0.6 kb in NCa cms and in maintainer line and an additional transcript of 1.2 kb in fertile F1. The relationship of expression of orf222, orf139, and atp9 with NCa sterility was discussed.

Single and Mitochondrial Gene Inheritance Disorder Prediction Using Machine Learning

One of the most difficult jobs in the post-genomic age is identifying a genetic disease from a massive amount of genetic data.Furthermore,the complicated genetic disease has a very diverse genotype,making it challenging to find genetic markers.This is a challenging process since it must be completed effectively and efficiently.This research article focuses largely on which patients are more likely to have a genetic disorder based on numerous medical parameters.Using the patient’s medical history,we used a genetic disease prediction algorithm that predicts if the patient is likely to be diagnosed with a genetic disorder.To predict and categorize the patient with a genetic disease,we utilize several deep and machine learning techniques such as Artificial neural network(ANN),K-nearest neighbors(KNN),and Support vector machine(SVM).To enhance the accuracy of predicting the genetic disease in any patient,a highly efficient approach was utilized to control how the model can be used.To predict genetic disease,deep and machine learning approaches are performed.The most productive tool model provides more precise efficiency.The simulation results demonstrate that by using the proposed model with the ANN,we achieve the highest model performance of 85.7%,84.9%,84.3%accuracy of training,testing and validation respectively.This approach will undoubtedly transform genetic disorder prediction and give a real competitive strategy to save patients’lives.

STUDY ON THE RELATIONSHIP BETWEEN MITOCHONDRIAL GENE MUTATION AND LATENT AUTOIMMUNE DIABETES MELLITUS IN ADULTS

Objective.To identify the A3243G mutation of mi tochondrial(mt )DNA in patients with latent autoimmu ne diabetes mellitus in adults(LADA)of Han nationality in the northeast a rea of China.Methods.Seventy-nine diabetics of Han natio nality,whose families have resided in the northeast area of China for more than 3generations,we re divided into 3groups:Group 1(22cases of type 2diabetes with mater-nal inheritance history),Group 2(34cases of LADA),Group 3(23cases of type 1diabetes in adolesc ents).The A3243G of mt DNA was detected in th ese 79subjects with the method of PCR-RFLP.Results.None of the 79diabetics studied was p ositively identified for the A3243G mutation of mt DNA.Conclusion.The A3243G mutation of mt DNA might not be related to the onset of LADA in dia betic popula-tion of Han nationality in northeast area of China and there might not be close relationship between A3243G mut a-tion of mt DNA and autoimmunity.

Functional analysis of the novel mitochondrial tRNA^(Trp)and tRNA^(Ser(AGY))variants associated with type 2 diabetes mellitus

BACKGROUND Mutations in mitochondrial tRNA(mt-tRNA)genes that result in mitochondrial dysfunction play important roles in type 2 diabetes mellitus(T2DM).We previously reported a large Chinese pedigree with maternally inherited T2DM that harbors novel mt-tRNA^(Trp)A5514G and tRNA^(Ser(AGY))C12237T variants,however,the effects of these mt-tRNA variants on T2DM progression are largely unknown.AIM To assess the potential pathogenicity of T2DM-associated m.A5514G and m.C12237T variants at genetic,molecular,and biochemical levels.METHODS Cytoplasmic hybrid(cybrid)cells carrying both m.A5514G and m.C12237T variants,and healthy control cells without these mitochondrial DNA(mtDNA)variants were generated using trans-mitochondrial technology.Mitochondrial features,including mt-tRNA steady-state level,levels of adenosine triphosphate(ATP),mitochondrial membrane potential(MMP),reactive oxygen species(ROS),mtDNA copy number,nicotinamide adenine dinucleotide(NAD+)/NADH ratio,enzymatic activities of respiratory chain complexes(RCCs),8-hydroxy-deoxyguanine(8-OhdG),malondialdehyde(MDA),and superoxide dismutase(SOD)were examined in cell lines with and without these mt-tRNA variants.RESULTS Compared with control cells,the m.A5514G variant caused an approximately 35%reduction in the steady-state level of mt-tRNA^(Trp)(P<0.0001);however,the m.C12237T variant did not affect the mt-tRNA^(Ser(AGY))steady-state level(P=0.5849).Biochemical analysis revealed that cells with both m.A5514G and m.C12237T variants exhibited more severe mitochondrial dysfunctions and elevated oxidative stress than control cells:ATP,MMP,NAD+/NADH ratio,enzyme activities of RCCs and SOD levels were markedly decreased in mutant cells(P<0.05 for all measures).By contrast,the levels of ROS,8-OhdG and MDA were significantly increased(P<0.05 for all measures),but mtDNA copy number was not affected by m.A5514G and m.C12237T variants(P=0.5942).CONCLUSION The m.A5514G variant impaired mt-tRNA^(Trp)metabolism,which subsequently caused mitochondrial dysfunction.The m.C12237T variant did not alter the steady-state level of mt-tRNA^(Ser(AGY)),indicating that it may be a modifier of the m.A5514G variant.The m.A5514G variant may exacerbate the pathogenesis and progression of T2DM in this Chinese pedigree.

Rice Mitochondrial Genes Are Transcribed by Multiple Promoters That Are Highly Diverged

Plant mitochondrial genes are often transcribed into complex sets of mRNA. To characterize the transcription initiation and promoter structure, the transcript termini of four mitochondrial genes, atpl, atp6, cob, rps7, in rice （Oryza sativa L.）, were determined by using a modified circularized RNA reverse transcription- polymerase chain reaction method. The results revealed that three genes （atp1, atp6, rps7） were transcribed from multiple initiation sites, indicating the presence of multiple promoters. Two transcription termination sites were detected in three genes （atp6, cob, rps7）, respectively. Analysis on the promoter architecture showed that the YRTA （Y=T or C, R=A or G） motifs that are widely present in the mitochondrlal promoters of other monocot and dicot plant species were detected only in two of the 12 analyzed promoters. Our data suggest that the promoter sequences in the rice mitochondrial genome are highly diverged in comparison to those in other plants, and the YRTA motif is not an essential element for the promoter activity.

DGGE Analysis on Mitochondrial Cyt b Gene of Eriocheir sinensis and Eriocheir hepuensis

[Objective] The aim was to investigate the possibility to analyze the genetic diversity of Eriocheir sinensis and Eriocheir hepuensis by using the technique denaturing gradient gel electrophoresis（DGGE）.[Method] Mitochondrial cyt b gene fragment was amplified from 180 individuals of five populations of E.sinensis and a population of E.hepuensis and then analyzed by using DGGE.[Result] All PCR products showed two kinds of electrophoretic mobility on DGGE.The PCR products of all individuals from E.hepuensis showed the same mobility with that of the individuals from 46.7% of Jiangdu population,23.3% of Yizheng population and 20.0% of Wenzhou population of E.sinensis,while the rest of the individuals from the three populations of E.sinensis mentioned above as well as all the individuals of Nanjing and Panjin populations showed the same mobility,which was higher compared with that of E.hepuensis.The results indicated that there was the same genetic marker in E.sinensis populations as that of E.hepuensis population,which was consistent with previous studies.[Conclusion] DGGE technique could be used to analyze the genetic diversity of Chinese mitten crab.

Allotopic expression of mitochondrial genes:Basic strategy and progress

Allotopic expression of mitochondrial genes is a deliberate functional relocation of mitochondrial genes into the nucleus followed by import of the gene-encoded polypeptide from the cytoplasm into the mitochondria.For successful allotopic expression of a mitochondrial gene,several key aspects must be considered.These include the different codon dictionary used by the mitochondrial and nuclear genomes,different codon preferences between mitochondrial and nuclear-cytosolic translation systems,and the provision of an import signal to ensure that the newly translated protein in the cytosol is successfully imported into mitochondria.The allotopic expression strategy was first developed in yeast,a useful model organism for studying human and other eukaryotic cells.Currently,a number of mitochondrial genes have been successfully recoded and nuclearly expressed in yeast and human cells.In addition to its use in evolutionary and molecular biology studies,the allotopic expression strategy has been developed as a potential approach to treat mitochondrial genetic disorders.Substantial progress has been recently achieved,and the development of this technique for therapy of the mitochondrial disease Leber’s hereditary optic neuropathy(LHON)has entered phase III clinical trials.However,a number of challenges remain to be overcome to accelerate the successful application of this technique.These include improvement of nuclear gene expression,import into mitochondria,processing,and functional integration of the allotopically expressed polypeptides into mitochondrial protein complexes.This review discusses the current basic strategy,progress,challenges,and prospects of the allotopic expression strategy for mitochondrial genes.

A preliminary phylogeny of Tipula and taxonomic placement of the subgenus Tipula (Sivatipula) (Diptera: Tipuloidea) based on mitochondrial COI gene

The large genus Tipula Linnaeus,1758 contributes heavily to the biodiversity of the family Tipulidae.However,the monophyly of Tipula has not yet been verified.The subgenus Sivatipula Alexander,1964 is possibly the most confusing subgeneric taxon in the genus Tipula because of its members’particularly long antenna and one-armed posterior immovable apodeme on semen pump,which makes its subgeneric position uncertain.In this research,the sequences of cytochrome oxidase I(COI)for 19 Tipula species and five taxa from other genera are analyzed.Considering the molecular evidence on genetic distance as well as phylogenetic analysis and morphological information,our results indicate that(1)the genus Tipula is not resolved as monophyletic in phylogeny based on neighbor joining(NJ)and maximum likelihood(ML)trees because the subgenus Sivatipula doesn’t form a monophyletic clade with the remaining subgenera of Tipula;and(2)Sivatipula may deserve a generic status since it forms an independent phylogenetic line.

Assembly and phylogenomic analysis of cotton mitochondrial genomes provide insights into the history of cotton evolution

Cotton is a major crop that provides the most important renewable textile fibers in the world.Studies of the taxonomy and evolution of cotton species have received wide attentions,not only due to cotton’s economic value but also due to the fact that Gossypium is an ideal model system to study the origin,evolution,and cultivation of polyploid species.Previous studies suggested the involvement of mitochondrial genome editing sites and copy number as well as mitochondrial functions in cotton fiber elongation.Whereas,with only a few mitogenomes assembled in the cotton genus Gossypium,our knowledge about their roles in cotton evolution and speciation is still scarce.To close this gap,here we assembled 20 mitogenomes from 15 cotton species spanning all the cotton clades(A–G,K,and AD genomes)and 5 cotton relatives using short and long sequencing reads.Systematic analyses uncovered a high level of mitochondrial gene sequence conservation,abundant sequence repeats and many insertions of foreign sequences,as well as extensive structural variations in cotton mitogenomes.The sequence repeats and foreign sequences caused significant mitogenome size inflation in Gossypium and its close relative Kokia in general,while there is no significant difference between the lint and fuzz cotton mitogenomes in terms of gene content,RNA editing,and gene expression level.Interestingly,we further revealed the specific presence and expression of two novel mitochondrial open reading frames(ORFs)in lint-fiber cotton species.Finally,these structural features and novel ORFs help us gain valuable insights into the history of cotton evolution and polyploidization and the origin of species producing long lint fibers from a mitogenomic perspective.

Genomic Analysis of Mitochondrial Carrier Genes in the Bombyx mori

This study is performed to investigate the mitochondrial carrier gene family in silkworm genome. In total, 30 genes are identified and claded into eight well-conserved groups. Gene duplication contributes to the expansion and complexity of this family. Diverse expression patterns suggest their functional differentiation. Analyses of the sitespecific profiles reveal critical amino acid residues for functional divergence. This study highlights the molecular evolution of the mitochondrial carrier gene family in silkworm and may provide a starting point for further experimental verification.

Genetic Differences of Mitten Crabs Based on RFLP Analysis on Mitochondrial Cytochrome Oxidase Subunit I(COI) Gene

The genetic differences of 15 mitten crab populations from 6 river systems in China's Mainland and 1 population from Russia were studied based on RFLP analysis of mitochondrial cytochrome oxidase subunit I （CO I）. The results showed that Tas I-RFLP pattern could be used as a genetic marker to distinguish Eriocheir hepuensis from Eriocheir sinensis, Eriocheirjaponica and Eriocheir leptognathus; genetic distances among 13 populations of Eriocheir sinensis range from 0 to 0.015, indicating that they were different geographic strains; the subspecies status of Eriocheir sinensis and Eriocheir hepuensis （population from Nanliujiang） were considered owning to their genetic distances of 0.02-0.044, indicating that genetic divergence between them was low; Eriocheir leptognathus （population from Nanpaihe, Tianjin） was the most distant taxon with genetic distances value of 0.147-0.195, which could be defined as genetic distances between species in genus Eriocheir.

The Genetic Structure and Diversity of Repomucenus curvicornis Inhabiting Liaoning Coast Based on Mitochondrial COⅠ Gene and Control Region

[Object] This study was conducted to explore the genetic diversity and structure of the wild Repomucenus curvicornis inhabiting Liaoning Coast, China. [Method] The mitochondrial COⅠ gene and control region（CR） were PCR amplified from the wild R. curvicornis populations from the Liaodong Bay（n=22） and the northern Yellow Sea（n=18）, sequenced and analyzed for genetic diversity. [Result] The contents of A, T, C and G of 624 bp COⅠ gene were 24.09%, 31.04%, 25.28%, and 19.59%, and those of 460 bp CR fragment were 32.96%, 32.80%, 14.86% and 19.38%, respectively. The total number of variable sites, average number of nucleotide differences（ k）, haplotype diversity（H） and nucleotide diversity（π） based on COⅠ gene were 38, 4.67,（0.96±0.02） and（0.007 5±0.004 2）, and those based on CR fragment were 26, 3.35,（0.97 ±0.02） and（0.007 3±0.004 3）, respectively. Based on mitochondrial COⅠ gene and CR, the genetic diversity of Liaodong Bay population was lower than that of the northern Yellow Sea population. The AMOVA analysis based on CR fragments revealed almost significant genetic divergence between the Liaodong Bay and the northern Yellow Sea populations, while there was no significant genetic divergence based on COⅠ gene. The results showed that CR and COⅠ gene are effective molecular markers for detecting the genetic diversity of R. curvicornis population, while CR is more reliable than COⅠ gene in detecting the genetic structure. [Conclusion] CR is an appropriate marker for genetic analysis of marine fish population.

Molecular phylogeny of thirteen species in the genus Formica(Hymenoptera: Formicidae) based on COI, COII, and Cyt b genes

Partial eytochrome oxidase subunits I （COI） and II （COII）, and cytochrome b （Cyt b） genes of thirteen species of the ant genus Formica were sequenced for molecular phylogenetic studies. The sequences were as follows： COI fragment, 657 bp; COl ＋ COIl fragments, approximately 900 bp, including the termination codon at the end of COI and the initiator codon at the beginning of COIl; and the Cyt b fragment, 777 bp. Results show that these three mitoehondrial genetic markers are similar in base composition. The contents of A ＋ T were 73.8% （COl） and 79.2% （COII）--higher than those of G ＋ C, which were 20.8% （COIl） and 26.2% （COI）, and strongly AT-biased. The highest A ＋ T contents were 89.9% （COI） and 93.7% （COII） on the third codon, whereas the lowest G content was 0.2% （COII） and 1.2% （Cyt b）. Molecular phylogenetic trees based on these mitoehondrial genes were reconstructed. Cataglyphis aenescens in the subfamily Formicinae was used as the outgroup, and Diacamma rugosum of the subfamily Ponerinae was used as an additional, distantly-related outgroup. Phylogenetic analysis showed that the differences among the species in the in-group were small, with genetic distance values less than 0.1. The greatest genetic distance was between E beijingensis and F. cunicularia. The results are in accord with those based on morphological features.

Phylogenetic Analyses Reveal a Unique Species of Elaphe(Serpentes,Colubridae)New to Science

The snakes comprising the monophyletic group referred to as ratsnakes are found throughout Asia,Europe and the New World.Recently,three snake samples likely belonging to the ratsnakes were collected in Zoige County,Sichuan Province,China.Species identity was difficult to delimit morphologically because the specimens were juveniles and partially damaged.Subsequently,a molecular phylogenetic approach was used.Portions of three mitochondrial genes(cyt b,ND4 and 12S rRNA) were sequenced and analyzed.The results showed that they were sister to the genus Elaphe.Very little genetic variation was found among the three samples.The minimum genetic distances between these samples and those within Elaphe were greater than any currently recognized species within the genus.We conclude that this likely represents a new species within the genus Elaphe.Adult specimens and a morphologic description are needed for further study.

Interspecies Phylogenetic Analysis of Clonorchis sinensis in High-incidence Areas of Hunan Province, China

Objective This study aims to investigate the infection of Clonorchis sinensis(C.sinensis)in highincidence areas of Hunan Province,China.The phylogenetic analysis of the C.sinensis species in the highly infected areas was carried out.Method Infection of the definitive human host and intermediate fish host by C.sinensis was investigated,and the mitochondrial genes cox1 and Nad1 were used as genetic markers for phylogenetic analysis.Results In 2016–2020,the average population infection rate of Hunan was 1.38%,while in Tongdao County the rate was up to 26.90%,and the highest fish infection rate was detected in Qiyang County(99.44%in the dorsal fin of crucian carp).High genetic sequence similarity was observed in the samples from Qiyang and Lengshuitan which exhibited high homology with those from Guangdong and Gansu,whereas the parasitic species from Tongdao was highly homologous with those located in high-latitude areas.Moreover,no significant difference was found in the gene sequence of the parasitic species in definitive hosts dogs and cats.Conclusion The systematically study of C.sinensis infection in the high-incidence areas will contribute greatly to the prevention and effectively controlling the spread of Clonorchis sinensis in Hunan Province The endemic of C.sinensis infection in Hunan Province is the result of co-action of local and foreign parasite species.

Low Genetic Polymorphism at the Cytochrome C Oxidase I in Silkworm Strains of the Brazilian Germplasm Bank

Nucleotide sequences have been used to distinguish species and specimens for many years. More recently, the use of a partial sequence of 650 bp of the cytochrome c oxidase I, COI mitochondrial gene, has been proposed for species identification, known as DNA barcodes. In this work, a short sequence of the DNA barcode is described—approximately 250 bp, named as “DNA mini-barcode”—to molecularly identify different silkworm strains maintained at the unique public Germplasm Bank of Bombyx mori, at the Universidade Estadual de Maringá, UEM, Brazil. Analysis revealed no significant differences among the silkworm strains. The phylogenetic tree obtained by the neighbor-joining method and K2P distance, in which specimens of B. mandarina were used as outgroup, clustered all the specimens of B. mori in a unique clade. Genetic variability detect within B. mori was low or nonexistent. In conclusion, the partial region of 250 bp of the mitochondrial gene COI herein analyzed may not be efficient to discriminate silkworm strains from the UEM Germplasm Bank of Bombyx mori.

Cryptic species composition and genetic diversity within Bemisia tabaci complex in soybean in India revealed by mtCOI DNA sequence

Bemisia tabaci is a cryptic species complex, causing signiifcant loss on many agricultural y important crops worldwide. Knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. Here we investigate the whitelfy species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely Asia I, Asia II 1, and Asia II 7. Al the haplotypes detected in the study could be assigned to these three cryptic species fol owing the species demarcation criteria of 3.5%divergence threshold. Of these, Asia II 1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species Asia II 7 showed localized distribu-tion. The Asia II 1 exhibited the highest haplotype diversity and Asia I showed high level of nucleotide diversity. There was a signiifcantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitelfy species in India and yel ow mosaic disease observed during sampling survey.

A single degenerated primer significantly improves COX1 barcoding performance in soil nematode community profiling

A new COX1 primer for soil nematode metabarcoding was designed,and this primer outperforms other commonly used COX1 primer pairs in species recovery and quantity of PCR products.•The lack of reference database is the main reason that led to the low species recovery in COX1 metabarcoding.•We expanded current NCBI database by adding 51 newly generated COX1 reference sequences.Microscopic nematodes play important roles in soil ecosystems and often serve as bioindicators of soil health.The identification of soil nematodes is often difficult due to their limited diagnostic characters and high phenotypic plasticity.DNA barcoding and metabarcoding techniques are promising but lack universal primers,especially for mitochondrial COX1 gene.In this study a degenerated COX1 forward primer COIFGED was developed.The primer pair(COIFGED/JB5GED)outperforms other four commonly used COX1 primer pairs in species recovery and quantity of polymerase chain reaction(PCR)products.In metabarcoding analysis,the reads obtained from the new primer pair had the highest sequencing saturation threshold and amplicon sequence variant(ASV)diversity in comparison to other COX1 as well as 18S rRNA primers.The annotation of ASVs suggested the new primer pair initially recovered 9 and 6 out of 25 genera from mock communities,respectively,outperformed other COX1 primers,but underperformed the widely used 18S NF1/18Sr2b primers(16 out of 25 genera).By supplementing the COX1 database with our reference sequences,we recovered an additional 6 mock community species bringing the tally closer to that obtained with 18S primers.In summary,our newly designed COX1 primers significantly improved species recovery and thus can be supplementary or alternative to the conventional 18S metabarcoding.

Prevalence and clinical characteristics of mitochondrial tRNA leu^((UUR))mt 3243 A→G and ND-1 gene mt 3316 G→A mutations in Chinese patients with type 2 diabetes

Objective To assess the prevalence of mitochondrial Trna leu(uuR)gene mt 3243 A→G mutation and ND-1 gene mt 3316 G→A mutation in Chinese type 2 diabetes.Methods 716 randomly selected,unrelated patients with type 2 diabetes were screened for the mutation with a PCR-RFLP technique.Results Three individuals with mitochondrial Trna leu(UUR)gene mt 3243 A→G mutation were identified,representing approximately 0.4% of the type 2 patients screened.Further screening of first-degree relatives of these 3 patients identified another 4 affected carriers.In comparison with type 2 diabetic patients without the mutation,these 7 carriers of the mt3243 mutation had:1)an earlier diagnosis age of diabetes(38.0 ±10.1 year vs 53.4± 10.0 year,P＜0.001);2)lower Body Mass Index(BMI)(19.5±2.0 kg/m2vs 24.9± 10.9 kg/m2,P ＜ 0.0001);and 3)lower post-challenge insulin levels(Area under the curve of insulin levels during the Oral Glucose Tolerance Test(OGTT),2946 ± 1647.2 μlU· ml-1 vs 7469 ± 6647.7 μlU·ml-1,P ＜ 0.01).ND-1 gene mt 3316 G→A mutation was found in 16 patients with type 2 diabetes(2.2%)and 5 out 181 controls(2.7%)with normal glucose tolerance.Therefore,the frequency of the mutation was not different in patients and controls.Moreover,clinical characteristics such as age of onset of diabetes,BMI,and insulin levels were not different between diabetic patients with the mt 3316 mutation and those without it.Conclusions In this large cohort of Chinese Type 2 diabetes,the prevalence of mitochondrial Trna leu(UUR)gene mt 3243 A→G mutation was 0.4%,and the ND-1 gene mt 3316 G→A mutation is a polymorphism unrelated to diabetes.

Relationship between mutations of mitochondrial DNA ND1 gene and type 2 diabetes

Background Recent studies have indicated that many mutations in mitochondrial (mt)DNA NDI gene region are related to diabetes mellitus. In this study we explored the relationship between various mtDNA ND1 gene mutations and type 2 diabetes mellitus (DM) among Chinese. Methods Using PCR restriction fragment length polymorphism (PCR-RFLP) analysis and gene sequencing, 4 spots of mtDNA (nt3243, nt3316, nt3394, nt3426) were screened in 478 diabetics and 430 non-diabetic subjects.Results In diabetic group, there were 13 carriers (2.72%)of 3316 G→A mutation,12 (2.51%) of 3394 T→C mutation and 2 (0.42%) of 3426A→G mutation. In controls, only 3394 T→C mutation was observed in 2 subjects (0.47%). There was significant difference in the frequency of 3316 and 3394 mutation between two groups (P<0.05, respectively). More subjects with mitochondrial DNA ND1 gene mutations had DM family history and greater tendency of maternal inheritance when compared to those patients without mutation in diabetic group(P<0.01). A 3426 mutation diabetic pedigree was studied, and we found 12 maternal members in the family had the same mutation. Conclusion mtDNA ND1 gene mutations at nt3316 (G→A), nt3394 (T→C) and 3426 (A→G) might contribute to the pathogenesis of DM with other genetic factors and environment factors.