Mitochondrial DNA polymorphisms in Yunnan nationalities in China

Nucleotide sequences of the D-loop region of human mitochondrial DNA from four Yunnan nationalities, Dai, Wa, Lahu, and Tibetan, were analyzed. Based on a comparison of 563-bp sequences in 99 people, 66 different sequence types were observed. Of these, 64 were unique to their respective populations, whereas only 2 types were shared between the Lahu and Wa nationalities. The D-loop sequence variation and phylogenetic analysis suggested that the 99 mtDNA lineages were classified into eight clusters in the phylogenetic tree. All lineages that had a 9-bp deletion in the COII/tRNA^Lys intergenic region appeared in one cluster in the D-loop tree, suggesting a single event of the deletion in the Yunnan nationalities studied. Genetic distances, based on net nucleotide diversities between populations including Han Chinese and mainland Japanese, revealed that the Dai, Wa, Lahu, and Han Chinese are closely related to each other, while Tibetan and mainland Japanese formed a single cluster. The bootstrap probabil-ity of separation between the Dai-Wa-Lahu-Chinese clade and the Tibetan-Japanese clade was 99%, indicating that there are at least two different origins among minority groups in Yunnan province. Although the genetic distance between Tibetan and Japanese within the clade is rather long, the results may shed light on the origins of mainland Japanese. Received: December 22, 2000 / Accepted: January 18, 2001     

Forensic utility of the feline mitochondrial control region – A Dutch perspective

Different portions of the feline mitochondrial DNA control region (CR) were evaluated for their informative value in forensic investigations. The 402 bp region located between RS2 and RS3 described most extensively in the past is not efficient for distinguishing between the majority of Dutch cats, illustrated by a random match probability (RMP) of 41%. Typing of the whole region between RS2 and RS3, and additional typing of the 5’portion of the feline CR decreases the RMP to 29%, increasing the applicability of such analyses for forensic investigations.The haplotype distribution in Dutch random bred cats (N = 113) differs greatly from the distributions reported for other countries, with a single haplotype NL-A1 present in 54% of the population. The three investigated breeds showed haplotype distributions differing from each other and the random bred cats with haplotype NL-A1 accounting for 4%, 29% and 32% of Maine Coon, Norwegian forest cats and Siamese & Oriental cats. These results indicate the necessity of validating haplotype frequencies within continents and regions prior to reporting the value a mtDNA match. In cases where known purebred cats are involved, further investigation of the breed may be valuable.     

Mutation in D-loop region of mitochondrial DNA in gastric cancer and its significance

AIM:To investigate the mutation in D-loop region of mitochondrial DNA in gastric cancer and its influence on the changes of reactive oxygen species (ROS) and cell cycle. METHODS: The D-loop region was amplified by PCR and sequenced.Reactive oxygen species and cell cycle were detected by flow cytometry in 20 specimens from gastric cancer and adjacent normal tissues.According to the sequence results,gastric cancer tissue was divided into mutation group and control group.Reactive oxygen species,apoptosis and proliferation in the two groups were compared. RESULTS:Among the 20 gastric cancer specimens, 18 mutations were identified in 7 patients,the mutation rate being 35%.There were four microsatellite instabilities in the mutations. No mutation was found in the adjacent tissues. Reactive oxygen species,apoptosis,and proliferation in the mutation group were all significantly higher than those in control group. CONCLUSION: Mutation in D-loop region plays a role in the genesis and development of gastric cancer.     

Mutations in the D-loop region of mitochondrial DNA in g astric cancer

Objective: To investigate the mutations in the D-loop region of mitochondrial DNA (mtDNA) in gastric cancer.Methods: The mtDNA of D-loop region was amplified by PCR and ,sequenced in 20 samples from gastric cancer tissue and adjacent normal membrane. Results: There were 7/20(35% ) mutations in the mtDNA of D-loop region in gastric cancer patients. There were four microsatellite instabilities among the 18 mutations. Nine new polymorphisms were identified in 20 patients. Conclusion: The mtDNA of D-loop region might be highly polymorphoric and the mutation rate is high in patients with gastric cancer.     

云南滇南小耳猪与广西巴马小型猪mtDNA D-Loop的初步研究

目的研究封闭群滇南小耳猪与广西巴马小型猪线粒体DNA（mtDNA）的多态性,探索小型猪遗传监测的方法。方法用18种限制性内切酶对23头滇南小耳猪和21头广西巴马小型猪mtDNA D-loop的PCR产物进行RFLP分析。结果滇南小耳猪和广西巴马小型猪的mtDNA D—loop在品种内和品种间均表现出相同的酶切图谱,未见多态性。结论滇南小耳猪与广西巴马小型猪mtDNA D—loop的遗传多样性贫乏,mtDNA PCR—RFLP技术在其遗传监测中不具应用价值。     

急性白血病线粒体D-loop区微卫星D310和D16184不稳定性研究

 目的　探讨线粒体 D-loop 区微卫星（MSI）D310 和 D16184 在急性白血病（AL）中的不稳定性。方法　采用反转录聚合酶链-单链构象多态性分析（PCR-SSCP）法筛选100例初诊未治及治疗的 AL 患者 D-loop 区 HV-1和 HV-2。对迁移异常者进行测序,结果与剑桥标准序列（rCRS）和mtDB数据库进行比对,分析其突变情况。比较各组组中 D310 和 D16184 的突变率。结果　100例AL患者中,D310总突变49例（49.0 %）,未治疗组40例中突变13例（32.5 %）,治疗组60例中突变36例（60.0 %）,治疗组高于未治疗组（P＜0.05）;D16184总突变32例（32.0 %）,未治疗组突变8例（20.0 %）,治疗组为24例（40.0 %）,治疗组高于未治疗组（P＜0.05）。结论　D310和D16184在AL中存在较高的突变率和多种突变类型,具有较强的不稳定性;化疗可能增强微卫星的不稳定性。     

Location and frequency of polymorphic positions in the mtDNA control region of individuals from Germany

In order to identify polymorphic positions and to determine their frequency in the human mitochondrial D-loop containing region, the mitochondrial DNA (mtDNA) control region of 200 unrelated individuals from Germany were amplified and directly sequenced. Sequence comparison led to the identification of 190 mitochondrial lineages as defined by 202 variable positions. The most frequently occurring lineage comprised 5 individuals, whereas 186 types of D-loop sequences were observed in only one individual. Of the sequences studied 7% are not unique but show at least one counterpart with an identical haplotype. The majority (61%) of the control regions investigated showed between four and eight nucleotide positions deviating from the reference sequence. The maximum number of deviations observed in a single control region was 18. The majority of the variable positions in the D-loop region (88%) are located within three hypervariable regions. Sequence variations are caused by nucleotide substitutions, insertions or deletions. As compared to insertions and deletions, nucleotide substitutions make up the vast majority of the mutations (90%). We have predominantly found transitions (75%) and a significantly lower frequency of transversions (15%) whereas insertions (6%) as well as deletions (4%) are rather rare. Upon sequencing the mitochondrial control region from 200 German Caucasians the genetic diversity was estimated at 0.99. The probability of two randomly selected individuals from a population having identical mtDNA types is 0.6%. Received: 21 May 1997 / Received in revised form: 9 September 1997     

Increased number of substitutions in the D-loop of mitochondrial DNA in the sudden infant death syndrome

The purpose of the present study was to investigate substitutions in the D-loop of mitochondrial DNA (mtDNA) in sudden infant death syndrome (SIDS) and controls, since several observations indicate the involvement of mtDNA mutations in SIDS. These include elevated levels of vitreous humour hypoxanthine in SIDS victims, familial clustering without mendelian traits, and observations of increased sleepiness and a lower activity score in infants who later succumbed to SIDS. Eighty-two cases of SIDS and 133 controls were investigated and the D-loop sequences were recorded in the base-pair range 16 055-16 500 in the mtDNA sequence. The sequencing was carried out using the Applied Biosystems Sequenase dye terminator method and a ABD373A sequencer. The recorded D-loop sequences were compared with the Cambridge sequence and differences were recorded as substitutions. The SIDS cases had a tendency towards a higher substitution rate in the D-loop than the controls ( p = 0.088). This observation makes it interesting to search for deleterious mutations in other locations in the mtDNA.     

贵州思南黄牛线粒体DNA D-loop区全序列多态性分析

为了解贵州思南黄牛的遗传多样性及遗传背景,我们测定了21个个体线粒体DNA D-loop区序列。检测到8种单倍型,4种为普通牛血统的单倍型,4种为瘤牛血统的单倍型,表明思南黄牛同时受普通牛和瘤牛的影响。这对于思南黄牛的保种及持续利用有着重要的理论指导意义。     

Study on the mutations in the D-loop region of mitochondrial DNA in cervical carcinoma

Background  Study on genesis and development of tumor is mainly concentrated on gene mutation in nucleus. But in recent years, the role of mitochondrial DNA (mtDNA) mutation in tumor genesis has been given more attention, which is the only extra-nucleus DNA in cells of higher animals. Carcinoma of the uterine cervix is a common tumor in gynecology. There are few reports of mtDNA mutation in this area. The focus of this study was to investigate the mitochondrial DNA mutation in tumor tissues of cervical carcinomas patients and their relationship to tumorigenesis and tumor development. Methods  The D-loop region of 24 cervical carcinomas together with the adjacent normal tissues were amplified by PCR and sequenced. Results  Among the 24 cervical carcinomas, 30 mutations were identified with the mutations rate of 37.5% (9/24).There were eight microsatellite instabilities among the mutations and 13 new polymorphisms which were not reported previously in the GeneBank. Conclusions  The D-loop region of mitochondrial DNA is a highly polymorphoric and mutable region and the mutations rate is relatively high in patients with cervical carcinomas. Daozhen Chen and Huiying Zhan contributed equally to this work.