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BACKGROUND: Early diagnosis is critical to lung adenocarcinoma patients' survival but faces inadequacies in convenient early detection. METHODS: We applied a comprehensive microarray of 130,000 peptides to detect "autoantibody signature" that is autoantibodies binding to mimotopes for early detection of stage 0-I LUAD. Plasma samples were collected from 147 early-stage lung adenocarcinoma (Early-LUAD), 108 benign lung disease (BLD), and 122 normal healthy controls (NHC). Clinical characteristics, low-dose CT (LDCT), and laboratory tests were incorporated into correlation analysis. RESULTS: We identified 143 and 133 autoantibody signatures, distinguishing Early-LUAD from NHC/BLD in the discovery cohort. Autoantibody signatures significantly correlated with age, stage, tumor size, basophil count, and IgM level (P < 0.05). The random forest models based on differential autoantibody signatures displayed AUC of 0.92 and 0.87 to discern Early-LUAD from NHC/BLD in the validation cohort, respectively. Compared with LDCT, combining autoantibody signature and LDCT improved the positive predictive value from 50% to 78.33% (P = 0.049). In addition, autoantibody signatures displayed higher sensitivity of 72.4% to 81.0% compared with the combinational tumor markers (cyfra21.1, NSE, SCC, ProGRP) with a sensitivity of 22.4% (P = 0.000). Proteins matched by differential peptides were enriched in cancer-related PI3K/Akt, MAPK, and Wnt pathways. Overlaps between matched epitopes and autoantibody signatures illustrated the underlying engagement of autoantibodies in immune recognition. CONCLUSIONS: Collectively, autoantibody signatures identified by a high-throughput peptide microarray have the potential to detect Early-LUAD, which could assist LDCT to better diagnose Early-LUAD. IMPACT: Novel sensitive autoantibody signatures can adjuvant LDCT to better diagnose LUAD at very early stage.
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Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Autoanticorpos , Fosfatidilinositol 3-Quinases , Detecção Precoce de Câncer , Adenocarcinoma de Pulmão/diagnóstico , PeptídeosRESUMO
FDR control has been a huge challenge for large-scale metabolome annotation. Although recent research indicated that the target-decoy strategy could be implemented to estimate FDR, it is hard to perform FDR control due to the difficulty of getting a reliable decoy database because of the complex fragmentation mechanism of metabolites and ubiquitous isomers. To tackle this problem, we developed a decoy generation method, which generates forged spectra from the reference target database by preserving the original reference signals to simulate the presence of isomers of metabolites. Benchmarks on GNPS data sets in Passatutto showed that the decoy database generated by our method is closer to the actual FDR than other methods, especially in the low FDR range (0-0.05). Large-scale metabolite annotation on 35 data sets showed that strict FDR reduced the number of annotated metabolites but increased the spectral efficiency, indicating the necessity of quality control. We recommended that the FDR threshold should be set to 0.01 in large-scale metabolite annotation. We implemented decoy generation, database search, and FDR control into a search engine called XY-Meta. It facilitates large-scale metabolome annotation applications.
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Algoritmos , Metabolômica , Peptídeos/metabolismo , Proteínas/metabolismo , Ferramenta de Busca , Bases de Dados de Proteínas , Peptídeos/análise , Proteínas/análiseRESUMO
Human identification and paternity testing are usually based on the study of STRs depending on their particular characteristics in the forensic investigation. In this paper, we developed a sensitive genotyping system, SiFaSTR™ 23-plex, which is able to characterize 18 expanded Combined DNA Index System STRs (D3S1358, D5S818, D2S1338, TPOX, CSF1PO, TH01, vWA, D7S820, D21S11, D10S1248, D8S1179, D1S1656, D18S51, D12S391, D19S433, D16S539, D13S317, and FGA), three highly polymorphic STRs among Chinese people (Penta D, Penta E, and D6S1043), one Y-chromosome Indel and amelogenin using a multiplex PCR; the PCR amplified products were analyzed using the Applied Biosystems 3500 Genetic Analyzer. Full genotyping profiles were obtained using only 31.25 pg of control DNA; various case-type specimens, as well as ten-year-old samples were also successfully genotyped. Additionally, in the validation studies, this multiplex was demonstrated to be human-specific and compatible with the interference of multiple PCR inhibitors. The system also enabled the detection of mixtures, and complete profiles could be obtained at the mixed ratios of 1:1, 1:3, and 3:1. The development and validation study here illustrated that the SiFaSTR™ 23-plex system is accurate, powerful, and more sensitive than many other systems. What's more, the population data in our study not only illustrated that this 23-plex typing system was straightforward and efficient but also expanded the Chinese STR database, which could facilitate the appropriate application of the 23 genetic markers in forensic genetics, especially in the Chinese population.
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Eletroforese Capilar/métodos , Repetições de Microssatélites/genética , Reação em Cadeia da Polimerase Multiplex/métodos , Povo Asiático , DNA/análise , DNA/genética , Feminino , Genética Forense/métodos , Técnicas de Genotipagem/métodos , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
STRs vary not only in the length of the repeat units and the number of repeats but also in the region with which they conform to an incremental repeat pattern. Massively parallel sequencing (MPS) offers new possibilities in the analysis of STRs since they can simultaneously sequence multiple targets in a single reaction and capture potential internal sequence variations. Here, we sequenced 34 STRs applied in the forensic community of China with a custom-designed panel. MPS performance were evaluated from sequencing reads analysis, concordance study and sensitivity testing. High coverage sequencing data were obtained to determine the constitute ratios and heterozygous balance. No actual inconsistent genotypes were observed between capillary electrophoresis (CE) and MPS, demonstrating the reliability of the panel and the MPS technology. With the sequencing data from the 200 investigated individuals, 346 and 418 alleles were obtained via CE and MPS technologies at the 34 STRs, indicating MPS technology provides higher discrimination than CE detection. The whole study demonstrated that STR genotyping with the custom panel and MPS technology has the potential not only to reveal length and sequence variations but also to satisfy the demands of high throughput and high multiplexing with acceptable sensitivity.
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Genética Forense/métodos , Genoma Humano , Sequenciamento de Nucleotídeos em Larga Escala/estatística & dados numéricos , Repetições de Microssatélites , Polimorfismo Genético , Alelos , China , Eletroforese Capilar , Feminino , Biblioteca Genômica , Genótipo , Heterozigoto , Humanos , Masculino , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Global disparities in prostate cancer (PCa) incidence highlight the urgent need to identify genomic abnormalities in prostate tumors in different ethnic populations including Asian men. OBJECTIVE: To systematically explore the genomic complexity and define disease-driven genetic alterations in PCa. DESIGN, SETTING, AND PARTICIPANTS: The study sequenced whole-genome and transcriptome of tumor-benign paired tissues from 65 treatment-naive Chinese PCa patients. Subsequent targeted deep sequencing of 293 PCa-relevant genes was performed in another cohort of 145 prostate tumors. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The genomic alteration landscape in PCa was analyzed using an integrated computational pipeline. Relationships with PCa progression and survival were analyzed using nonparametric test, log-rank, and multivariable Cox regression analyses. RESULTS AND LIMITATIONS: We demonstrated an association of high frequency of CHD1 deletion with a low rate of TMPRSS2-ERG fusion and relatively high percentage of mutations in androgen receptor upstream activator genes in Chinese patients. We identified five putative clustered deleted tumor suppressor genes and provided experimental and clinical evidence that PCDH9, deleted/loss in approximately 23% of tumors, functions as a novel tumor suppressor gene with prognostic potential in PCa. Furthermore, axon guidance pathway genes were frequently deregulated, including gain/amplification of PLXNA1 gene in approximately 17% of tumors. Functional and clinical data analyses showed that increased expression of PLXNA1 promoted prostate tumor growth and independently predicted prostate tumor biochemical recurrence, metastasis, and poor survival in multi-institutional cohorts of patients with PCa. A limitation of this study is that other genetic alterations were not experimentally investigated. CONCLUSIONS: There are shared and salient genetic characteristics of PCa in Chinese and Caucasian men. Novel genetic alterations in PCDH9 and PLXNA1 were associated with disease progression. PATIENT SUMMARY: We reported the first large-scale and comprehensive genomic data of prostate cancer from Asian population. Identification of these genetic alterations may help advance prostate cancer diagnosis, prognosis, and treatment.
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Utilizing massively parallel sequencing (MPS) technology for SNP testing in forensic genetics is becoming attractive because of the shortcomings of STR markers, such as their high mutation rates and disadvantages associated with the current PCR-CE method as well as its limitations regarding multiplex capabilities. MPS offers the potential to genotype hundreds to thousands of SNPs from multiple samples in a single experimental run. In this study, we designed a customized SNP panel that includes 273 forensically relevant identity SNPs chosen from SNPforID, IISNP, and the HapMap database as well as previously related studies and evaluated the levels of genotyping precision, sequence coverage, sensitivity and SNP performance using the Ion Torrent PGM. In a concordant study of the custom MPS-SNP panel, only four MPS callings were missing due to coverage reads that were too low (<20), whereas the others were fully concordant with Sanger's sequencing results across the two control samples, that is, 9947A and 9948. The analyses indicated a balanced coverage among the included loci, with the exception of the 16 SNPs that were used to detect an inconsistent allele balance and/or lower coverage reads among 50 tested individuals from the Chinese HAN population and the above controls. With the exception of the 16 poorly performing SNPs, the sequence coverage obtained was extensive for the bulk of the SNPs, and only three Y-SNPs (rs16980601, rs11096432, rs3900) showed a mean coverage below 1000. Analyses of the dilution series of control DNA 9948 yielded reproducible results down to 1ng of DNA input. In addition, we provide an analysis tool for automated data quality control and genotyping checks, and we conclude that the SNP targets are polymorphic and independent in the Chinese HAN population. In summary, the evaluation of the sensitivity, accuracy and genotyping performance provides strong support for the application of MPS technology in forensic SNP analysis, and the assay offers a straightforward sample-to-genotype workflow that could be beneficial in forensic casework with respect to both individual identification and complex kinship issues.
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Sequenciamento de Nucleotídeos em Larga Escala/métodos , Polimorfismo de Nucleotídeo Único , Povo Asiático/genética , China , Etnicidade/genética , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Reação em Cadeia da Polimerase Multiplex , SoftwareRESUMO
The custom-designed single nucleotide polymorphism (SNP) panel amplified 231 autosomal SNPs in one PCR reaction and subsequently sequenced with massively parallel sequencing (MPS) technology and Ion Torrent personal genome machine (PGM). SNPs were chosen from SNPforID, IISNP, HapMap, dbSNP, and related published literatures. Full concordance was obtained between available MPS calling and Sanger sequencing with 9947A and 9948 controls. Ten SNPs (rs4606077, rs334355, rs430046, rs2920816, rs4530059, rs1478829, rs1498553, rs7141285, rs12714757 and rs2189011) with low coverage or heterozygote imbalance should be optimized or excluded from the panel. Sequence data had sufficiently high coverage and gave reliable SNP calling for the remaining 221 loci with the custom MPS-SNP panel. A default DNA input amount of 10 ng per reaction was recommended by Ampliseq technology but sensitivity testing revealed positive results from as little as 1 ng input DNA. Mixture testing with this panel is possible through analysis of the F MAR (frequency of major allele reads) values at most loci with enough high coverage depth and low level of sequencing noise. These results indicate the potential advantage of the custom MPS-SNP assays and Ion Torrent PGM platform for forensic study.
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INTRODUCTION: The incidence rate of lung adenocarcinoma (LUAD), the predominant histological subtype of lung cancer, is elevated in Asians, particularly in female nonsmokers. The mutation patterns in LUAD in Asians might be distinct from those in LUAD in whites. METHODS: We profiled 271 resected LUAD tumors (mainly stage I) to characterize the genomic landscape of LUAD in Asians with a focus on female nonsmokers. RESULTS: Mutations in EGFR, KRAS, erb-b2 receptor tyrosine kinase 2 gene (ERBB2), and BRAF; gene fusions involving anaplastic lymphoma receptor tyrosine kinase gene (ALK), ROS1, and ret proto-oncogene (RET); and Met Proto-Oncogene Tyrosine Kinase (MET) exon 14 skipping were the major drivers in LUAD in Asians, exhibiting mutually exclusive and differing prevalence from those reported in studies of LUAD in non-Asians. In addition, we identified a novel mutational signature of XNX (the mutated base N in the middle flanked by two identical bases at the 5' and 3' positions) that was overrepresented in LUAD tumors in nonsmokers and negatively correlated with the overall mutational frequency. CONCLUSIONS: In this cohort, approximately 85% of individuals have known driver mutations (EGFR 59.4%, KRAS 7.4%, ALK 7.4%, ERBB2 2.6%, ROS1 2.2%, RET 2.2%, MET 1.8%, BRAF 1.1%, and NRAS 0.4%). Seventy percent of smokers and 90% of nonsmokers had defined oncogenic drivers matching the U.S. Food and Drug Administration-approved targeted therapies.
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Adenocarcinoma/genética , Povo Asiático/genética , Carcinogênese/genética , Neoplasias Pulmonares/genética , Adenocarcinoma/patologia , Adenocarcinoma de Pulmão , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Proto-Oncogene Mas , Adulto JovemRESUMO
SNPs, abundant in human genome with lower mutation rate, are attractive to genetic application like forensic, anthropological and evolutionary studies. Universal SNPs showing little allelic frequency variation among populations while remaining highly informative for human identification were obtained from previous studies. However, genotyping tools target only dozens of markers simultaneously, limiting their applications. Here, 124 SNPs were simultaneous tested using Ampliseq technology with Ion Torrent PGM platform. Concordance study was performed with 2 reference samples of 9947A and 9948 between NGS and Sanger sequencing. Full concordance were obtained except genotype of rs576261 with 9947A. Parameter of FMAR (%) was introduced for NGS data analysis for the first time, evaluating allelic performance, sensitivity testing and mixture testing. FMAR values for accurate heterozygotes should be range from 50% to 60%, for homozygotes or Y-SNP should be above 90%. SNPs of rs7520386, rs4530059, rs214955, rs1523537, rs2342747, rs576261 and rs12997453 were recognized as poorly performing loci, either with allelic imbalance or with lower coverage. Sensitivity testing demonstrated that with DNA range from 10 ng-0.5 ng, all correct genotypes were obtained. For mixture testing, a clear linear correlation (R(2) = 0.9429) between the excepted FMAR and observed FMAR values of mixtures was observed.
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Antropologia Forense/métodos , Polimorfismo de Nucleotídeo Único/genética , Semicondutores , Análise de Sequência de DNA/métodos , Povo Asiático/genética , Sequência de Bases , DNA/genética , Etnicidade/genética , Frequência do Gene/genética , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Dados de Sequência Molecular , SoftwareRESUMO
The human genome is diploid, and knowledge of the variants on each chromosome is important for the interpretation of genomic information. Here we report the assembly of a haplotype-resolved diploid genome without using a reference genome. Our pipeline relies on fosmid pooling together with whole-genome shotgun strategies, based solely on next-generation sequencing and hierarchical assembly methods. We applied our sequencing method to the genome of an Asian individual and generated a 5.15-Gb assembled genome with a haplotype N50 of 484 kb. Our analysis identified previously undetected indels and 7.49 Mb of novel coding sequences that could not be aligned to the human reference genome, which include at least six predicted genes. This haplotype-resolved genome represents the most complete de novo human genome assembly to date. Application of our approach to identify individual haplotype differences should aid in translating genotypes to phenotypes for the development of personalized medicine.
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Genoma Humano , Haplótipos/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Medicina de Precisão , Povo Asiático/genética , Sequência de Bases , Mapeamento Cromossômico , Diploide , Genótipo , Humanos , Fenótipo , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNARESUMO
We did whole-transcriptome sequencing and whole-genome sequencing on nine pairs of Hepatocellular carcinoma (HCC) tumors and matched adjacent tissues to identify RNA editing events. We identified mean 26,982 editing sites with mean 89.5% canonical AâG edits in each sample using an improved bioinformatics pipeline. The editing rate was significantly higher in tumors than adjacent normal tissues. Comparing the difference between tumor and normal tissues of each patient, we found 7 non-synonymous tissue specific editing events including 4 tumor-specific edits and 3 normal-specific edits in the coding region, as well as 292 edits varying in editing degree. The significant expression changes of 150 genes associated with RNA editing were found in tumors, with 3 of the 4 most significant genes being cancer related. Our results show that editing might be related to higher gene expression. These findings indicate that RNA editing modification may play an important role in the development of HCC.
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Carcinoma Hepatocelular/genética , Genoma , Neoplasias Hepáticas/genética , Edição de RNA , Transcriptoma , Biologia Computacional/métodos , Estudo de Associação Genômica Ampla , Humanos , Análise de Sequência de RNARESUMO
Single-cell sequencing is a powerful tool for delineating clonal relationship and identifying key driver genes for personalized cancer management. Here we performed single-cell sequencing analysis of a case of colon cancer. Population genetics analyses identified two independent clones in tumor cell population. The major tumor clone harbored APC and TP53 mutations as early oncogenic events, whereas the minor clone contained preponderant CDC27 and PABPC1 mutations. The absence of APC and TP53 mutations in the minor clone supports that these two clones were derived from two cellular origins. Examination of somatic mutation allele frequency spectra of additional 21 whole-tissue exome-sequenced cases revealed the heterogeneity of clonal origins in colon cancer. Next, we identified a mutated gene SLC12A5 that showed a high frequency of mutation at the single-cell level but exhibited low prevalence at the population level. Functional characterization of mutant SLC12A5 revealed its potential oncogenic effect in colon cancer. Our study provides the first exome-wide evidence at single-cell level supporting that colon cancer could be of a biclonal origin, and suggests that low-prevalence mutations in a cohort may also play important protumorigenic roles at the individual level.
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Sequenciamento de Nucleotídeos em Larga Escala , Simportadores/metabolismo , Proteína da Polipose Adenomatosa do Colo/genética , Proteína da Polipose Adenomatosa do Colo/metabolismo , Subunidade Apc3 do Ciclossomo-Complexo Promotor de Anáfase/genética , Subunidade Apc3 do Ciclossomo-Complexo Promotor de Anáfase/metabolismo , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Oncogenes , Proteínas de Ligação a Poli(A)/genética , Proteínas de Ligação a Poli(A)/metabolismo , Análise de Componente Principal , Análise de Sequência de DNA , Simportadores/química , Simportadores/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Cotransportadores de K e Cl-RESUMO
Ultra-low coverage sequencing (ULCS) is one of the most promising strategies for sequencing based clinical application. These clinical applications, especially prenatal diagnosis, have a strict requirement of turn-around-time; therefore, the application of ULCS is restricted by current high throughput sequencing platforms. Recently, the emergence of rapid sequencing platforms, such as MiSeq and Ion Proton, brings ULCS strategy into a new era. The comparison of their performance could shed lights on their potential application in large-scale clinic trials. In this study, we performed ULCS (<0.1X coverage) on both MiSeq and Ion Proton platforms for 18 spontaneous abortion fetuses carrying aneuploidy and compared their performance on different levels. Overall basic data and GC bias showed no significant difference between these two platforms. We also found the sex and aneuploidy detection indicated 100% sensitivity and 100% specificity on both platforms. Our study generated essential data from these two rapid sequencing platforms, which provides useful reference for later research and potentially accelerates the clinical applications of ULCS.
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Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequenciamento de Nucleotídeos em Larga Escala/normas , Aneuploidia , Composição de Bases/genética , Feminino , Humanos , Masculino , Cromossomos Sexuais/genéticaRESUMO
BACKGROUND: To gain biological insights into lung metastases from hepatocellular carcinoma (HCC), we compared the whole-genome sequencing profiles of primary HCC and paired lung metastases. METHODS: We used whole-genome sequencing at 33X-43X coverage to profile somatic mutations in primary HCC (HBV+) and metachronous lung metastases (> 2 years interval). RESULTS: In total, 5,027-13,961 and 5,275-12,624 somatic single-nucleotide variants (SNVs) were detected in primary HCC and lung metastases, respectively. Generally, 38.88-78.49% of SNVs detected in metastases were present in primary tumors. We identified 65-221 structural variations (SVs) in primary tumors and 60-232 SVs in metastases. Comparison of these SVs shows very similar and largely overlapped mutated segments between primary and metastatic tumors. Copy number alterations between primary and metastatic pairs were also found to be closely related. Together, these preservations in genomic profiles from liver primary tumors to metachronous lung metastases indicate that the genomic features during tumorigenesis may be retained during metastasis. CONCLUSIONS: We found very similar genomic alterations between primary and metastatic tumors, with a few mutations found specifically in lung metastases, which may explain the clinical observation that both primary and metastatic tumors are usually sensitive or resistant to the same systemic treatments.
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Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Genoma Humano/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Análise de Sequência de DNA , Adulto , Variações do Número de Cópias de DNA/genética , Análise Mutacional de DNA , Progressão da Doença , Evolução Fatal , Frequência do Gene/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Metástase Neoplásica , Sítios de Splice de RNA/genética , Transdução de Sinais/genéticaRESUMO
Hepatocellular carcinoma (HCC) is one of the most deadly cancers worldwide and has no effective treatment, yet the molecular basis of hepatocarcinogenesis remains largely unknown. Here we report findings from a whole-genome sequencing (WGS) study of 88 matched HCC tumor/normal pairs, 81 of which are Hepatitis B virus (HBV) positive, seeking to identify genetically altered genes and pathways implicated in HBV-associated HCC. We find beta-catenin to be the most frequently mutated oncogene (15.9%) and TP53 the most frequently mutated tumor suppressor (35.2%). The Wnt/beta-catenin and JAK/STAT pathways, altered in 62.5% and 45.5% of cases, respectively, are likely to act as two major oncogenic drivers in HCC. This study also identifies several prevalent and potentially actionable mutations, including activating mutations of Janus kinase 1 (JAK1), in 9.1% of patients and provides a path toward therapeutic intervention of the disease.
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Carcinoma Hepatocelular/genética , Genoma Humano , Neoplasias Hepáticas/genética , Mutação , Sequência de Aminoácidos , Carcinoma Hepatocelular/virologia , DNA Viral/genética , Feminino , Vírus da Hepatite B/genética , Humanos , Janus Quinase 1/genética , Neoplasias Hepáticas/virologia , Masculino , Dados de Sequência Molecular , Fatores de Transcrição STAT/genética , Análise de Sequência de DNA , Proteína Supressora de Tumor p53/genética , Integração Viral , Via de Sinalização Wnt/genética , beta Catenina/genéticaRESUMO
BACKGROUND: The applications of massively parallel sequencing technology to fetal cell-free DNA (cff-DNA) have brought new insight to non-invasive prenatal diagnosis. However, most previous research based on maternal plasma sequencing has been restricted to fetal aneuploidies. To detect specific parentally inherited mutations, invasive approaches to obtain fetal DNA are the current standard in the clinic because of the experimental complexity and resource consumption of previously reported non-invasive approaches. METHODS: Here, we present a simple and effective non-invasive method for accurate fetal genome recovery-assisted with parental haplotypes. The parental haplotype were firstly inferred using a combination strategy of trio and unrelated individuals. Assisted with the parental haplotype, we then employed a hidden Markov model to non-invasively recover the fetal genome through maternal plasma sequencing. RESULTS: Using a sequence depth of approximately 44X against a an approximate 5.69% cff-DNA concentration, we non-invasively inferred fetal genotype and haplotype under different situations of parental heterozygosity. Our data show that 98.57%, 95.37%, and 98.45% of paternal autosome alleles, maternal autosome alleles, and maternal chromosome X in the fetal haplotypes, respectively, were recovered accurately. Additionally, we obtained efficient coverage or strong linkage of 96.65% of reported Mendelian-disorder genes and 98.90% of complex disease-associated markers. CONCLUSIONS: Our method provides a useful strategy for non-invasive whole fetal genome recovery.
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The genetic diversity of Yersinia pestis, the etiologic agent of plague, is extremely limited because of its recent origin coupled with a slow clock rate. Here we identified 2,326 SNPs from 133 genomes of Y. pestis strains that were isolated in China and elsewhere. These SNPs define the genealogy of Y. pestis since its most recent common ancestor. All but 28 of these SNPs represented mutations that happened only once within the genealogy, and they were distributed essentially at random among individual genes. Only seven genes contained a significant excess of nonsynonymous SNP, suggesting that the fixation of SNPs mainly arises via neutral processes, such as genetic drift, rather than Darwinian selection. However, the rate of fixation varies dramatically over the genealogy: the number of SNPs accumulated by different lineages was highly variable and the genealogy contains multiple polytomies, one of which resulted in four branches near the time of the Black Death. We suggest that demographic changes can affect the speed of evolution in epidemic pathogens even in the absence of natural selection, and hypothesize that neutral SNPs are fixed rapidly during intermittent epidemics and outbreaks.
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Evolução Molecular , Deriva Genética , Variação Genética , Taxa de Mutação , Yersinia pestis/genética , Sequência de Bases , China , Genética Populacional , Funções Verossimilhança , Modelos Genéticos , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNARESUMO
De novo mutation plays an important role in autism spectrum disorders (ASDs). Notably, pathogenic copy number variants (CNVs) are characterized by high mutation rates. We hypothesize that hypermutability is a property of ASD genes and may also include nucleotide-substitution hot spots. We investigated global patterns of germline mutation by whole-genome sequencing of monozygotic twins concordant for ASD and their parents. Mutation rates varied widely throughout the genome (by 100-fold) and could be explained by intrinsic characteristics of DNA sequence and chromatin structure. Dense clusters of mutations within individual genomes were attributable to compound mutation or gene conversion. Hypermutability was a characteristic of genes involved in ASD and other diseases. In addition, genes impacted by mutations in this study were associated with ASD in independent exome-sequencing data sets. Our findings suggest that regional hypermutation is a significant factor shaping patterns of genetic variation and disease risk in humans.
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Transtorno Autístico/genética , Estudo de Associação Genômica Ampla , Mutação em Linhagem Germinativa , Taxa de Mutação , Animais , Linhagem Celular , Éxons , Feminino , Humanos , Masculino , Idade Materna , Pan troglodytes/genética , Idade Paterna , Análise de Sequência de DNA , Gêmeos MonozigóticosRESUMO
To survey hepatitis B virus (HBV) integration in liver cancer genomes, we conducted massively parallel sequencing of 81 HBV-positive and 7 HBV-negative hepatocellular carcinomas (HCCs) and adjacent normal tissues. We found that HBV integration is observed more frequently in the tumors (86.4%) than in adjacent liver tissues (30.7%). Copy-number variations (CNVs) were significantly increased at HBV breakpoint locations where chromosomal instability was likely induced. Approximately 40% of HBV breakpoints within the HBV genome were located within a 1,800-bp region where the viral enhancer, X gene and core gene are located. We also identified recurrent HBV integration events (in ≥ 4 HCCs) that were validated by RNA sequencing (RNA-seq) and Sanger sequencing at the known and putative cancer-related TERT, MLL4 and CCNE1 genes, which showed upregulated gene expression in tumor versus normal tissue. We also report evidence that suggests that the number of HBV integrations is associated with patient survival.
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Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/virologia , Vírus da Hepatite B/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/virologia , Integração Viral/genética , Sequência de Bases , Instabilidade Cromossômica/genética , Ciclina E/genética , Variações do Número de Cópias de DNA/genética , DNA Viral/genética , Proteínas de Ligação a DNA/genética , Feminino , Histona-Lisina N-Metiltransferase , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteínas Oncogênicas/genética , RNA Viral/genética , Taxa de Sobrevida , Telomerase/genéticaRESUMO
Tumor heterogeneity presents a challenge for inferring clonal evolution and driver gene identification. Here, we describe a method for analyzing the cancer genome at a single-cell nucleotide level. To perform our analyses, we first devised and validated a high-throughput whole-genome single-cell sequencing method using two lymphoblastoid cell line single cells. We then carried out whole-exome single-cell sequencing of 90 cells from a JAK2-negative myeloproliferative neoplasm patient. The sequencing data from 58 cells passed our quality control criteria, and these data indicated that this neoplasm represented a monoclonal evolution. We further identified essential thrombocythemia (ET)-related candidate mutations such as SESN2 and NTRK1, which may be involved in neoplasm progression. This pilot study allowed the initial characterization of the disease-related genetic architecture at the single-cell nucleotide level. Further, we established a single-cell sequencing method that opens the way for detailed analyses of a variety of tumor types, including those with high genetic complex between patients.