Application Of Next-generation Sequencing Technologies Research Articles

Whole-Exome Sequencing Targeting a Gene Panel for Sensorineural Hearing Loss: The First Portuguese Cohort Study

Next-generation sequencing (NGS) technologies revolutionized the molecular diagnosis of sensorineural hearing loss (SNHL) and are now a standard of care. In this study, 71 Portuguese probands with hereditary SNHL were assessed by whole-exome sequencing (WES) targeting a panel of 158 genes related to SNHL, aiming to evaluate the diagnostic yield of this methodological approach and to report the spectrum of variants. Patients with either nonsyndromic or syndromic SNHL were included. Also, patients were previously screened for variants in the GJB2 gene and for duplications/deletions in the GJB6 gene. Causative variants in 11 different genes were identified in 15 (21.1%) out of 71 probands, 5 of which had associated syndromes. In 6 other patients (8.5%), presumptive causative variants were identified in MYO15A, TMIE, TBC1D24, SPMX, GJB3, PCDH15, and CDH23 genes, uncovering a potential case of digenic Usher syndrome. The study was inconclusive in 20 probands (28.2%), in 19 due to lack of segregation analysis and in one due to uncertain phenotype-genotype matching. In the remaining 30 patients (42.3%) no potentially causative variants were identified. The diagnostic yield did not significantly vary according to the age of hearing-impairment onset. As the first study on the application of NGS technologies in SNHL based on a Portuguese cohort, our results may contribute to characterize the spectrum of variants related to SNHL in the Portuguese population. Additionally, the present study provides new insights into the contribution of MYO3A, TECTA, EDNRB, TBC1D24, and GJB3 genes to SNHL. For the significant number of undiagnosed patients, reanalysis of WES data – either for a broader gene panel or in a non-targeted approach – may be considered.

Parental mosaicism for apparent de novo genetic variants: Scope, detection, and counseling challenges.

The disease burden of de novo mutations (DNMs) has been evidenced only recently when the common application of next-generation sequencing technologies enabled their reliable and affordable detection through family-based clinical exome or genome sequencing. Implementation of exome sequencing into prenatal diagnostics revealed that up to 63% of pathogenic or likely pathogenic variants associated with fetal structural anomalies are apparently de novo, primarily for autosomal dominant disorders. Apparent DNMs have been considered to primarily occur as germline or zygotic events, with consequently negligible recurrence risks. However, there is now evidence that a considerable proportion of them are in fact inherited from a parent mosaic for the variant. Here, we review the burden of DNMs in prenatal diagnostics and the influence of parental mosaicism on the interpretation of apparent DNMs and discuss the challenges with detecting and quantifying parental mosaicism and its effect on recurrence risk. We also describe new bioinformatic and technological tools developed to assess mosaicism and discuss how they improve the accuracy of reproductive risk counseling when parental mosaicism is detected.

Dispersion characteristics of oral microbial communities in a built environment

AbstractAdvances in next‐generation sequencing (NGS) technologies since 2005 have revolutionized biological science. One particular application of NGS technologies is to elucidate microbiomes in built environments. We are currently conducting a series of studies on the elucidation and control of mass infection mechanisms based on dynamic measurement of environment microbiomes. The objective of this study is to clarify the dispersion characteristics of oral bacteria in the built environment. Bacterial communities from occupants’ hands and oral cavities, doorknobs, desk and keyboard surfaces, and air in laboratories were investigated in seven Japanese universities. The median relative abundances of Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Fusobacteria were 41%, 31%, 12%, 7%, and 3%, respectively. Moreover, the main genera detected were Streptococcus (27.6%), Haemophilus (7.0%), Staphylococcus (5.6%), Neisseria (5.6%), Corynebacterium (4.7%), Rothia (3.2%), Prevotella (3.0%), Fusobacterium (2.6%), Veillonella (1.7%), Leptotrichia (1.7%), Enhydrobacter (1.7%), Lactobacillus (1.3%), Acinetobacter (1.3%), and Actinomyces (1.1%). The oral bacteria Actinomyces, Corynebacterium, Fusobacterium, Haemophilus, Leptotrichia, Neisseria, Prevotella, Rothia, and Streptococcus were observed in indoor air and on surfaces as well as in oral cavities. Furthermore, Prevotella melaninogenica and Rothia mucilaginosa were observed in all samples, including those from hands and oral cavities, doorknobs, desk and PC keyboard surfaces, and air in laboratories, in all seven universities.

An insight into the fecal microbiota composition in Romanian patients with ankylosing spondylitis using high-throughput 16S rRNA gene amplicon sequencing

Abstract Introduction. Application of next-generation sequencing technology generated a massive amount of information on the gut microbiome composition used to understand its role in the healthy state and in various diseases. We aimed to provide information on the gut microbiota composition of Romanian subjects diagnosed with ankylosing spondylitis, an immune-mediated arthropathy linked to a genetic predisposition and gut dysbiosis. Methods. Stool samples collected from 25 patients with ankylosing spondylitis and 16 healthy controls were investigated using high-throughput DNA sequencing of 16S rRNA amplicons from seven different hypervariable regions and Ion Torrent PGM instrument. Microbial composition of metagenomic data was analyzed with QIIME software and differential abundance analysis of taxa encompassed linear discriminant analysis effect size (LEfSe). Results. Overall, 14 phyla, 114 families, 114 genera, and 275 species were identified across the 41 samples, the aggregated data revealing as most abundant the phyla Bacteroidetes, Firmicutes, and Proteobacteria, the families Bacteroidaceae, Prevotellaceae, and Ruminococcaceae, the genera Bacteroides, Prevotella, and Faecalibacterium, and Prevotella copri species. Using various cutoffs for abundance and prevalence, core taxonomic members were identified which in general were shared between the patients and controls. However, evidence was gained that the diversity in the microbiomes from the former cohort was lower than for controls and that certain taxa had significantly different abundance between the two groups. Conclusion. This study allowed an informative high-throughput 16S rRNA profiling of the gut microbiota needed to identify microbiome signatures of risk in the autochthonous population with AS.

Genetic diversity and population structure of rice (Oryza sativa L.) landraces from Kerala, India analyzed through genotyping-by-sequencing.

Researchers stand at the vanguard of advancement and application of next-generation sequencing technology for developing dominant strategies for the sustainable management of genetically diverse crops. We attempt to fill the existing research lacuna in the molecular characterization of potent rice landraces in Kerala. Genotyping-by-sequencing (GBS) was performed on 96 Kerala rice accessions to identify single-nucleotide polymorphisms (SNPs), to examine the genetic diversity, population structure, and to delineate linkage disequilibrium (LD) pattern. GBS identified 5856 high-quality SNPs. The structure analysis indicated three subpopulations with the highest probability for population clustering with significant genetic differentiation, confirmed by principal component analysis. The genome-wide LD decay distance was 772kb, at which the r2 dropped to half its maximum value. The analysis of genetic properties of the identified SNP panel with an average polymorphism information content (PIC) value of 0.22 and a minor allele frequency (MAF) > 0.1 unveiled their efficacy in genome-wide association studies (GWAS). High FST (0.266) and low Nm (0.692) portray a strong genetic differentiation among the rice landraces, complementing the genetic structuring observed in the studied population. Slow LD decay in the rice landraces reflects their self-pollinating behavior and the indirect selection of desired traits by domestication. Moreover, the high LD entails only a minimum number of SNP markers for detecting marker-trait association. The diverse germplasm utilized in this study can be further utilized to disclose genetic variants associated with phenotypic traits and define signatures of selection via GWAS and selective sweep, respectively.

A narrative review of prognosis prediction models for non-small cell lung cancer: what kind of predictors should be selected and how to improve models?

ObjectiveTo discover potential predictors and explore how to build better models by summarizing the existing prognostic prediction models of non-small cell lung cancer (NSCLC).BackgroundResearch on clinical prediction models of NSCLC has experienced explosive growth in recent years. As more predictors of prognosis are discovered, the choice of predictors to build models is particularly important, and in the background of more applications of next-generation sequencing technology, gene-related predictors are widely used. As it is more convenient to obtain samples and follow-up data, the prognostic model is preferred by researchers.MethodsPubMed and the Cochrane Library were searched using the items “NSCLC”, “prognostic model”, “prognosis prediction”, and “survival prediction” from 1 January 1980 to 5 May 2021. Reference lists from articles were reviewed and relevant articles were identified.ConclusionsThe performance of gene-related models has not obviously improved. Relative to the innovation and diversity of predictors, it is more important to establish a highly stable model that is convenient for clinical application. Most of the prevalent models are highly biased and referring to PROBAST at the beginning of the study may be able to significantly control the bias. Existing models should be validated in a large external dataset to make a meaningful comparison.

Application of next-generation sequencing technology in prenatal screening and diagnosis

Developed rapidly for more than ten years, next-generation sequencing (NGS) has derived a series of new technologies which are widely used clinically, such as noninvasive prenatal testing(NIPT), noninvasive prenatal testing-plus(NIPT Plus), copy number variation sequencing(CNV-seq), and exome sequencing(ES), and plays an important role in birth defects prevention. Moreover, with in-deep development, the superiority of NGS is gradually recognized by clinicians, but there are still many challenges in practical application process. This study specifically elaborates on the development status, technological breakthroughs and future prospects of NGS in the field of prenatal screening and prenatal diagnosis at home and abroad.

Application of Next-Generation Sequencing Technology Based on Single Gene Locus in Species Identification of Mixed Meat Products

Polymerase chain reaction (PCR) detection is a commonly used method for species identification of meat products. However, this method is not suitable for the analysis of meat products containing multiple mixtures. This study aimed to test whether next-generation sequencing (NGS) technology could be used as a method for the certification of mixed meat products. In this study, five kinds of common meat (pigs, cattle, sheep, chickens, and ducks) were mixed as samples with different proportions. The primers designed from mitochondrial 16S rRNA and nuclear genome gene (growth hormone receptor, GHR), respectively, were used to detect these meats. The sequencing results of NGS were analyzed using a self-designed bioinformatics program. The fragments with similar sequences were classified and compared with the database to determine their species. The results showed that all five kinds of meat components could be correctly identified using these two primers. The meat composition could be detected as low as 0.5% in the mixed samples using the NGS technology targeting GHR gene fragments, which was superior to those targeting mitochondrial 16S rRNA. However, the quantitative detection of species in the mixture was not likely to be quite accurate due to the amplification bias of PCR amplification. These results showed that the NGS technology could be applied to identify meat species in mixtures.

A review of consensus statements, practice resources, standards and guidelines for clinical applications of next-generation sequencing technologies in the United States

The use of whole exome sequencing (WES) for the detection of disease-causing variants of genetic diseases and for non-invasive prenatal screening (NIPS) of fetal aneuploidies are two major clinical applications of next generation sequencing (NGS). This article has summarized the official documents developed and updated by the American College of Medical Genetics and Genomics (ACMG) on governing WES and NIPS. These include the development of expert consensus policies and position statements on an ongoing basis to guide clinical application of NGS technology and variant analysis, establish evidence-based practical resources, as well as standards and guidelines to govern diagnosis and screening. These ACMG documents are valuable references to Chinese geneticists, but direct adoption of these standards and guidelines may not be practical due to the differences in disease-associated variant frequencies in Chinese population, socioeconomic status, and medical practice between the two countries. It is hoped that this review could facilitate the development of NGS and NIPS standards and guidelines that are consistent with international standards and concordant with medical genetics practice in China to provide high-quality, efficient and safe clinical services for patients and their families with genetic diseases.

Application of next-generation sequencing technology detecting ctDNA in the diagnosis and treatment of gastric cancer

Gastric cancer is a malignant tumor with high morbidity and mortality, which is a serious threat to human life and health. At present, the diagnosis and course monitoring of gastric cancer mainly rely on gastroscopic biopsy and CT, but their invasiveness and delay limit their clinical value. Gastric cancer patients urgently need a real-time, accurate, non-invasive diagnosis and course monitoring method. Circulating tumor DNA(ctDNA) is single or double stranded DNA released into body fluid by tumor cells, which contains the same genetic mutations as the original tumor cells. It is also one of the newly emerged biological markers. With the emergence and development of next-generation sequencing(NGS) technology, the sensitivity and specificity of ctDNA detection continue to increase, and it is gradually becoming a new choice for tumor diagnosis and disease course monitoring. In this paper, the current application of the next-generation sequencing technology detecting ctDNA in diagnosis and treatment of gastric cancer was discussed.

DEEPGENTM—A Novel Variant Calling Assay for Low Frequency Variants

Detection of genetic variants in clinically relevant genomic hot-spot regions has become a promising application of next-generation sequencing technology in precision oncology. Effective personalized diagnostics requires the detection of variants with often very low frequencies. This can be achieved by targeted, short-read sequencing that provides high sequencing depths. However, rare genetic variants can contain crucial information for early cancer detection and subsequent treatment success, an inevitable level of background noise usually limits the accuracy of low frequency variant calling assays. To address this challenge, we developed DEEPGENTM, a variant calling assay intended for the detection of low frequency variants within liquid biopsy samples. We processed reference samples with validated mutations of known frequencies (0%–0.5%) to determine DEEPGENTM’s performance and minimal input requirements. Our findings confirm DEEPGENTM’s effectiveness in discriminating between signal and noise down to 0.09% variant allele frequency and an LOD(90) at 0.18%. A superior sensitivity was also confirmed by orthogonal comparison to a commercially available liquid biopsy-based assay for cancer detection.

The Prognostic Significance of ZNF384 Fusions in Adult Ph-Negative B-Cell Precursor Acute Lymphoblastic Leukemia: A Comprehensive Cohort Study From a Single Chinese Center.

Novel recurrent fusion gene types such as zinc finger protein 384 (ZNF384) fusions have been identified in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with the application of next-generation sequencing technologies. However, the comprehensive large-scale clinical cohort study for clarifying their prognostic significance remains scarce to date. A total of 242 consecutive adult Ph-negative BCP-ALL patients treated in our institute were retrospectively screened ZNF384 fusions at diagnosis by multiplex real time quantitative PCR. ZNF384 fusions were identified in 47 patients (19.4%) and all belonged to B-other ALL (having no high hyperdiploid karyotype, BCR-ABL1, TCF3-PBX1, ETV6-RUNX1, or MLL rearrangement). In the whole cohort, patients with ZNF384 fusions had significantly higher 3-year relapse-free-survival (RFS) and tended to have a higher 3-year overall survival (OS) than those with no ZNF384 fusions (80.1% vs. 52.5%, P = 0.013; 67.6% vs. 54.0%, P = 0.10). For patients receiving chemotherapy alone and received allogeneic-hematologic stem cell transplantation (allo-HSCT) were censored at the time of transplantation, patients with ZNF384 fusions had both similar RFS and similar OS to B-other ALL patients with no ZNF384 fusions (RFS: P =0.94 and 0.30; OS: P =0.94 and 0.51). For patients receiving transplantation, those with ZNF384 fusions had significantly higher 3-year RFS than B-other ALL patients with no ZNF384 fusions and their OS were similar (P = 0.022 and 0.24). Only two of 31 patients with ZNF384 fusions and receiving allo-HSCT relapsed, individually occurred 66.8 and 69.8 months after transplantation. Therefore, ZNF384 fusion is common in adult BCP-ALL, which may define a new group from BCP-ALL containing no classical fusion transcript with better prognosis through receiving allo-HSCT.

Trends in Molecular Testing of Lung Cancer in Mainland People’s Republic of China Over the Decade 2010 to 2019

IntroductionLung cancer is the leading cause of cancer-related morbidity and mortality in the People’s Republic of China. Targeted therapies for patients with lung cancer, which depend on accurate identification of actionable genomic alteration, have improved survival compared with previously available treatments. However, data on the types of molecular testing often used in the People’s Republic of China, and how they have changed over time, are scarce. We explored the overall landscape of molecular testing of lung cancer in mainland People’s Republic of China in the past decade. MethodsWe distributed a stratified random sampling survey of molecular testing to 49 hospitals from members of the Molecular Pathology Collaboration Group of Chinese Anti-Cancer Association which was weighted by the numbers of lung cancer cases in seven different geographic regions in mainland People’s Republic of China from 2010 to 2019. The questionnaire contained four parts for all respondents. The questionnaire ascertained the use of approved in vitro diagnostic (IVD) devices published by the Center for Medical Device Evaluation, National Medical Products Administration of the People’s Republic of China. ResultsA total of 226,227 NSCLC specimens were tested from 2010 to 2019 in the selected hospitals. The annual number of initiated molecular tests increased over time (p < 0.0001), with an average annual growth rate of 31.8%. A notable increase in the number of molecular tests occurred during 2014 and 2016, which coincided with the approval of the National Medical Products Administration to IVD devices. For the diagnosis of molecular subtypes, EGFR mutation testing was first conducted in year 2007, followed by ALK translocation testing in 2010 and ROS1 in 2011. For other rare genetic variations in NSCLC, BRAF mutation testing was first launched in 2012, MET exon 14 skipping mutation in 2014, HER2 exon 20 mutations in 2017, and RET translocation in 2015. A markedly uneven distribution was also observed in the geography of leading units with the largest number of leading units located in east People’s Republic of China (34.7%, 17 of 49) and the smallest number located in northwest People’s Republic of China (6.1%, 3 of 49). The growth trends we observed illustrate the progress and increasing capability of molecular testing of lung cancer achieved in mainland People’s Republic of China in the decade from 2010. ConclusionsIn the decade 2010 to 2019, progress and increased capability of molecular testing of lung cancer were achieved in mainland People’s Republic of China. Further efforts should address the clinical application of next-generation sequencing technology, rare genomic aberrations, and the balance between novel genomic testing techniques and the approval of IVD products.

Variation analysis of genes associated with Usher syndrome type 1 in 136 Chinese deafness families

Objective: To investigate the variation of genes associated with Usher syndrome type 1(USH1)in 136 Chinese deafness families from Henan province. Methods: The data of 136 deafness families tested by next-generation sequencing(NGS) which identified in the center of genetics and prenatal diagnosis of the First Affiliated Hospital of Zhengzhou University from November 2016 to December 2019 were analysized and the variation frequency of six genes related to Usher syndrome type 1(MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2) were summarized. Results: Five deafness families were detected nine pathogenic or likely pathogenic variations in two genes, accounting for 3.7% of all families. Among them, four families were caused by MYO7A variations and one family was caused by CDH23 variation. Meanwhile, seven variations of two genes were reported for the first time. They were c.313delG, c.5257dupA, c.5435A>T, c.5636G>C, c.5722T>G of MYO7A, and c.155_166del, c.4802delA of CDH23. The patients' vision of family 2 and family 3 had no obvious abnormality at present, but according to genetic diagnosis and walking dealy, they were considered to be USH1. Conclusions: MYO7A is the most common caustive gene associated with USH1 in Henan deafness patients, the application of next-generation sequencing technology can make USH1 patients diagnosed earlier before the visual symptoms appear.

Transcriptome based high-throughput SSRs and SNPs discovery in the medicinal plant Lagenaria siceraria

<i>Lagenaria siceraria</i> (Molina) Standley has unique biological characteristics with high nutritional and medicinal values. It is an important pharmaceutical plant with various biologically active ingredients. Genetic improvement and deeper genomic studies require a rich resource of molecular markers. The application of next-generation sequencing technology, especially for transcriptome profiling, has greatly facilitated high throughput single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) discovery. In this study, we sequenced the transcriptome of three major cultivars of <i>L. siceraria</i> and obtained 64.88 GB of clean data. The assembled high-quality reads were clustered into 89,347 unigenes, which were annotated by non-redundant protein database, Swiss-Port, Eukaryotic Ortholog Groups, Kyoto Encyclopedia of Genes and Genomes, and gene ontology databases. A total of 8,891 SSR and 35,873 SNP markers were predicted from unigenes by MISA and SAM tools, respectively. Characterization of the predicted markers in <i>L. siceraria</i> showed that the SSR and SNP densities were 60 and 243 markers per Mb of genome, respectively, and the estimated ratio of transition to transversion of SNP was 2.016. These markers will be very useful for genetic studies in <i>L. siceraria</i>, especially for the high-density linkage map construction and genome-wide association studies. Further genomic studies based on these results will facilitate the identification of novel genes or alleles of pharmaceutical importance.

Global Analysis of the Human RNA Degradome Reveals Widespread Decapped and Endonucleolytic Cleaved Transcripts.

RNA decay is an important regulatory mechanism for gene expression at the posttranscriptional level. Although the main pathways and major enzymes that facilitate this process are well defined, global analysis of RNA turnover remains under-investigated. Recent advances in the application of next-generation sequencing technology enable its use in order to examine various RNA decay patterns at the genome-wide scale. In this study, we investigated human RNA decay patterns using parallel analysis of RNA end-sequencing (PARE-seq) data from XRN1-knockdown HeLa cell lines, followed by a comparison of steady state and degraded mRNA levels from RNA-seq and PARE-seq data, respectively. The results revealed 1103 and 1347 transcripts classified as stable and unstable candidates, respectively. Of the unstable candidates, we found that a subset of the replication-dependent histone transcripts was polyadenylated and rapidly degraded. Additionally, we identified 380 endonucleolytically cleaved candidates by analyzing the most abundant PARE sequence on a transcript. Of these, 41.4% of genes were classified as unstable genes, which implied that their endonucleolytic cleavage might affect their mRNA stability. Furthermore, we identified 1877 decapped candidates, including HSP90B1 and SWI5, having the most abundant PARE sequences at the 5′-end positions of the transcripts. These results provide a useful resource for further analysis of RNA decay patterns in human cells.

Building Skills and Resources for Genomics, Epigenetics, and Bioinformatics Research for Africa: Report of the Joint 11th Conference of the African Society of Human Genetics and 12th H3Africa Consortium, 2018.

.The 11th Congress of the African Society of Human Genetics (AfSHG) was held from September 16, 2018 to September 21, 2018, in conjunction with the 12th Human Heredity and Health in Africa (H3Africa) Consortium meeting in Kigali, Rwanda. The event was organized by the AfSHG in partnership with the Rwanda Society of Human Genetics and the University of Rwanda. A 2-day workshop on the application of next-generation sequencing technologies for analyzing monogenic disease in African populations was organized as part of the conference (September 22, 2018−September 23, 2018, Kigali, Rwanda). The theme of the conference was “Building skills and resources for genomics, epigenetics and bioinformatics research for Africa.” The conference served as a platform to bring together members from country-specific Societies of Human Genetics, including Rwanda, Cameroon, Democratic Republic of Congo, Egypt, Mali, Senegal, and South Africa, and included 435 delegates from 38 countries, including 29 African countries that attended the conference. A major topic of discussion was how to bridge the gap between the emerging knowledge on genomics and Omics in African populations. The importance of understanding the role of genetic variation in disease causation and susceptibility among Africans was a constant theme during the meeting, as was the need to develop research infrastructure and resources to enhance healthcare systems, so that they are not left behind in the genomic revolution. It was concluded that there is a need to inspire more African scientists to train and work as investigators, clinicians, and genetic counselors in the field of human genetics in Africa. Local investments, and South–South and South–North collaboration were identified as the key drivers for the successful implementation of research and development on the continent.

Clinical Interpretation of Sequence Variants.

Clinical interpretation of DNA sequence variants is a critical step in reporting clinical genetic testing results. Application of next-generation sequencing technology in molecular genetic testing has facilitated diagnoses of genetic disorders in clinical practice. However, the large number of DNA sequence variants detected in clinical specimens, many of which have never been seen before, make clinical interpretation challenging. Recommendations by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) have been widely adopted by clinical laboratories around the world to guide clinical interpretation of sequence variants. The ClinGen Sequence Variant Interpretation Working Group and various disease-specific variant curation expert panels have also developed specifications for the ACMG/AMP recommendations. Despite these efforts to standardize variant interpretation in clinical practice, different laboratories may subjectively use professional judgment to determine which criteria are applicable when classifying a variant. In addition, clinicians and researchers who are not familiar with the variant interpretation process may have difficulty understanding clinical genetic reports and communicating the clinical significance of genetic testing results. Here we provide a step-by-step protocol for clinical interpretation of sequence variants, including practical examples. By following this protocol, clinical laboratory geneticists can interpret the clinical significance of sequence variants according to the ACMG/AMP recommendations and ClinGen framework. Furthermore, this article will help clinicians and researchers to understand variant classification in clinical genetic testing reports and evaluate the quality of the reports. © 2020 by John Wiley & Sons, Inc. Basic Protocol: Interpreting the clinical significance of sequence variants Support Protocol: Reevaluating the clinical significance of sequence variants.

Progress in finding pathogenic DNA copy number variations in dyslipidemia.

DNA copy number variations (CNVs) are large-scale mutations that include deletions and duplications larger than 50 bp in size. In the era when single-nucleotide variations were the major focus of genetic technology and research, CNVs were largely overlooked. However, CNVs clearly underlie a substantial proportion of clinical disorders. Here, we update recent progress in identifying CNVs in dyslipidemias. Until last year, only the LDLR and LPA genes were appreciated as loci within which clinically relevant CNVs contributed to familial hypercholesterolemia and variation in Lp(a) levels, respectively. Since 2017, next-generation sequencing panels have identified pathogenic CNVs in at least five more genes underlying dyslipidemias, including a PCSK9 whole-gene duplication in familial hypercholesterolemia; LPL, GPIHBP1, and APOC2 deletions in hypertriglyceridemia; and ABCA1 deletions in hypoalphalipoproteinemia. CNVs are an important class of mutation that contribute to the molecular genetic heterogeneity underlying dyslipidemias. Clinical applications of next-generation sequencing technologies need to consider CNVs concurrently with familiar small-scale genetic variation, given the likely implications for improved diagnosis and treatment.

Applications of Next-Generation Sequencing Technologies and Computational Tools in Molecular Evolution and Aquatic Animals Conservation Studies: A Short Review.

Aquatic ecosystems that form major biodiversity hotspots are critically threatened due to environmental and anthropogenic stressors. We believe that, in this genomic era, computational methods can be applied to promote aquatic biodiversity conservation by addressing questions related to the evolutionary history of aquatic organisms at the molecular level. However, huge amounts of genomics data generated can only be discerned through the use of bioinformatics. Here, we examine the applications of next-generation sequencing technologies and bioinformatics tools to study the molecular evolution of aquatic animals and discuss the current challenges and future perspectives of using bioinformatics toward aquatic animal conservation efforts.