scholarly journals Detecting Selection on Segregating Gene Duplicates in a Population

2020 ◽  
Author(s):  
Tristan Stark ◽  
Rebecca Kaufman ◽  
Maria Maltepes ◽  
David Liberles
Keyword(s):  
Copy Number ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Effective Population ◽  
Phenotypic Differences ◽  
Adaptive Diversification ◽  
Moran Model ◽  
Fundamental Process ◽  
Population Sizes ◽  
Gene Duplicates

Gene duplication is a fundamental process that has the potential to drive phenotypic differences between populations and species. While evolutionarily neutral changes have the potential to affect phenotypes, detecting selection acting on gene duplicates can uncover cases of adaptive diversification. Existing methods to detect selection on duplicates work mostly inter-specifically and are based upon selection on coding sequence changes, here we present a method to detect selection directly on a copy number variant segregating in a population. The method relies upon expected relationships between allele (new duplication) age and frequency in the population dependent upon the effective population size. Using both a haploid and a diploid population with a Moran Model under several population sizes, the neutral baseline for copy number variants is established. The ability of the method to reject neutrality for duplicates with known age (measured in pairwise dS value) and frequency in the population is established through mathematical analysis and through simulations. Power is particularly good in the diploid case and with larger effective population sizes, as expected. With extension of this method to larger population sizes, this is a tool to analyze selection on copy number variants in any natural or experimentally evolving population.

scholarly journals Exome sequencing in patients with antiepileptic drug exposure and complex phenotypes

2019 ◽  
Vol 105 (4) ◽  
pp. 384-389 ◽  
Author(s):  
Adam Jackson ◽  
Heather Ward ◽  
Rebecca Louise Bromley ◽  
Charulata Deshpande ◽  
Pradeep Vasudevan ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Copy Number ◽  
Developmental Disorders ◽  
Drug Exposure ◽  
Genetic Disorders ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
In Utero ◽  
Developmental Problems ◽  
Number Of Children

IntroductionFetal anticonvulsant syndrome (FACS) describes the pattern of physical and developmental problems seen in those children exposed to certain antiepileptic drugs (AEDs) in utero. The diagnosis of FACS is a clinical one and so excluding alternative diagnoses such as genetic disorders is essential.MethodsWe reviewed the pathogenicity of reported variants identified on exome sequencing in the Deciphering Developmental Disorders (DDD) Study in 42 children exposed to AEDs in utero, but where a diagnosis other than FACS was suspected. In addition, we analysed chromosome microarray data from 10 patients with FACS seen in a Regional Genetics Service.ResultsSeven children (17%) from the DDD Study had a copy number variant or pathogenic variant in a developmental disorder gene which was considered to explain or partially explain their phenotype. Across the AED exposure types, variants were found in 2/15 (13%) valproate exposed cases and 3/14 (21%) carbamazepine exposed cases. No pathogenic copy number variants were identified in our local sample (n=10).ConclusionsThis study is the first of its kind to analyse the exomes of children with developmental disorders who were exposed to AEDs in utero. Though we acknowledge that the results are subject to bias, a significant number of children were identified with alternate diagnoses which had an impact on counselling and management. We suggest that consideration is given to performing whole exome sequencing as part of the diagnostic work-up for children exposed to AEDs in utero.

scholarly journals Detection and characterization of copy number variants based on whole-genome sequencing by DNBSEQ platforms

2019 ◽  
Author(s):  
Junhua Rao ◽  
Lihua Peng ◽  
Fang Chen ◽  
Hui Jiang ◽  
Chunyu Geng ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Whole Genome ◽  
Genome Wide ◽  
Wide Range ◽  
Distribution Sensitivity ◽  
Cnv Detection

AbstractBackgroundNext-generation sequence (NGS) has rapidly developed in past years which makes whole-genome sequencing (WGS) becoming a more cost- and time-efficient choice in wide range of biological researches. We usually focus on some variant detection via WGS data, such as detection of single nucleotide polymorphism (SNP), insertion and deletion (Indel) and copy number variant (CNV), which playing an important role in many human diseases. However, the feasibility of CNV detection based on WGS by DNBSEQ™ platforms was unclear. We systematically analysed the genome-wide CNV detection power of DNBSEQ™ platforms and Illumina platforms on NA12878 with five commonly used tools, respectively.ResultsDNBSEQ™ platforms showed stable ability to detect slighter more CNVs on genome-wide (average 1.24-fold than Illumina platforms). Then, CNVs based on DNBSEQ™ platforms and Illumina platforms were evaluated with two public benchmarks of NA12878, respectively. DNBSEQ™ and Illumina platforms showed similar sensitivities and precisions on both two benchmarks. Further, the difference between tools for CNV detection was analyzed, and indicated the selection of tool for CNV detection could affected the CNV performance, such as count, distribution, sensitivity and precision.ConclusionThe major contribution of this paper is providing a comprehensive guide for CNV detection based on WGS by DNBSEQ™ platforms for the first time.

scholarly journals HandyCNV: Standardized Summary, Annotation, Comparison, and Visualization of Copy Number Variant, Copy Number Variation Region, and Runs of Homozygosity

2021 ◽  
Vol 12 ◽  
Author(s):  
Jinghang Zhou ◽  
Liyuan Liu ◽  
Thomas J. Lopdell ◽  
Dorian J. Garrick ◽  
Yuangang Shi
Keyword(s):  
Copy Number ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
R Package ◽  
Copy Number Variation Region ◽  
Runs Of Homozygosity ◽  
Number Variation ◽  
Genomic Studies ◽  
Computing Platforms ◽  
Analysis System

Detection of CNVs (copy number variants) and ROH (runs of homozygosity) from SNP (single nucleotide polymorphism) genotyping data is often required in genomic studies. The post-analysis of CNV and ROH generally involves many steps, potentially across multiple computing platforms, which requires the researchers to be familiar with many different tools. In order to get around this problem and improve research efficiency, we present an R package that integrates the summarization, annotation, map conversion, comparison and visualization functions involved in studies of CNV and ROH. This one-stop post-analysis system is standardized, comprehensive, reproducible, timesaving, and user-friendly for researchers in humans and most diploid livestock species.

scholarly journals The prenatal diagnosis and clinical outcomes of fetuses with 15q11.2 copy number variants: a case series of 36 patients

2021 ◽  
Author(s):  
Jessica Kang ◽  
Chien Nan Lee ◽  
Yi-Ning Su ◽  
Ming-Wei Lin ◽  
Yi-Yun Tai ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Developmental Delay ◽  
Copy Number ◽  
De Novo ◽  
Copy Number Variants ◽  
Case Series ◽  
Copy Number Variant ◽  
University Hospital ◽  
Limited Information ◽  
Ultrasound Findings

Objective: The prenatal genetic counseling of fetus diagnosed with the 15q11.2 copy number variant (CNV) involving the BP1-BP2 region has been difficult due to limited information and controversial opinion on prognosis. Design: Case series. Setting: This study uses data from National Taiwan University Hospital. Sample: Data of 36 pregnant women who underwent prenatal microarray analysis from 2012 to 2017 and were assessed at National Taiwan University Hospital. Methods: Data were collected by reviewing patients’ medical record. Comparison of patient characteristics, prenatal ultrasound findings and postnatal outcomes between different cases involving the 15q11.2 BP1-BP2 region were presented. Main outcome measured: Postnatal prognosis. Results: Out of the 36 patients diagnosed with CNVs involving the BP1-BP2 region, 5 were diagnosed with microduplication and 31 with microdeletion. Abnormal ultrasound findings were recorded in 12 cases prenatally. De novo microduplications were observed in 25% of the cases and microdeletions were found in 14%. Amongst the cases, 10 pregnant women received termination of pregnancy and 26 gave birth to healthy individuals (27 babies in total). Conclusion: The prognoses of 15q11.2 CNVs were controversial and recent studies have revealed its connection with developmental delay and autism. In our study, no obvious developmental delay or neurological disorders were detected postnatally in the 1 case of 15q11.2 microduplication and 25 cases of microdeletion.

scholarly journals Copy number variants in clinical WGS: deployment and interpretation for rare and undiagnosed disease

2018 ◽  
Author(s):  
Andrew M Gross ◽  
Subramanian S. Ajay ◽  
Vani Rajan ◽  
Carolyn Brown ◽  
Krista Bluske ◽  
...  
Keyword(s):  
Copy Number ◽  
De Novo ◽  
Genetic Disorders ◽  
Diagnostic Testing ◽  
Copy Number Variants ◽  
Uniparental Disomy ◽  
Copy Number Variant ◽  
Break Point ◽  
Clinically Significant ◽  
Family Based

AbstractPurposeCurrent diagnostic testing for genetic disorders involves serial use of specialized assays spanning multiple technologies. In principle, whole genome sequencing (WGS) has the potential to detect all genomic mutation types on a single platform and workflow. Here we sought to evaluate copy number variant (CNV) calling as part of a clinically accredited WGS test.MethodsUsing a depth-based copy number caller we performed analytical validation of CNV calling on a reference panel of 17 samples, compared the sensitivity of WGS-based variants to those from a clinical microarray, and set a bound on precision using orthogonal technologies. We developed a protocol for family-based analysis, annotation, filtering, visualization of WGS based CNV calls, and deployed this across a clinical cohort of 79 rare and undiagnosed cases.ResultsWe found that CNV calls from WGS are at least as sensitive as those from microarrays, while only creating a modest increase in the number of variants interpreted (~10 CNVs per case). We identified clinically significant CNVs in 15% of the first 79 cases analyzed. This pipeline also enabled identification of cases of uniparental disomy (UPD) and a 50% mosaic trisomy 14. Directed analysis of some CNVs enabled break-point level resolution of genomic rearrangements and phasing of de-novo CNVs.ConclusionRobust identification of CNVs by WGS is possible within a clinical testing environment, and further developments will bring improvements in resolution of smaller and more complex CNVs.

T Cells of Patients with Myelodysplastic Syndrome Are Frequently Derived From the Malignant Clone

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2808-2808
Author(s):  
Suzanne Vercauteren ◽  
Daniel T. Starczynowski ◽  
Sandy Sung ◽  
Kelly McNeil ◽  
Chris Salski ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Copy Number ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Common Finding ◽  
Comparative Genomic ◽  
Trisomy 8 ◽  
T Cell Clonality ◽  
Cell Clonality

Abstract Abstract 2808 T cell clonality is a common finding in myelodysplastic syndromes (MDS), but is believed to be a reactive phenomenon. We compared copy number abnormalities in matched CD34+ progenitor cells and CD3+ T cells from 40 MDS patients by array comparative genomic hybridization. In 9 of 14 patients with large copy number variants, we detected the same aberration in CD34+ and CD3+ cells. Chromosome 20q (2 patients), isodicentric × chromosome (2 patients), trisomy 8 (2 patients), 11q abnormalities (1 patient), deletion 5q (1 patient) and partial trisomy 9 with trisomies 19 and 22 (1 patient) were detected in the CD34+ and CD3+ cells of these patients. The presence of deletion 20q, trisomy 8 and deletion of chromosome arm 11q in the T cells of 3 patients was confirmed by FISH. Multiplex PCR for TCR γ rearrangement was performed on 6 of the 14 MDS patients with large copy number variants. T cell clonality was detected in 3 of 4 and oligoclonality in 1 of 4 patients when the copy number variant was present in both CD34+ and CD3+ cells. In contrast, the 2 cases lacking the CD34+ copy number variant in the CD3+ population were polyclonal at the TCR γ locus. These data suggest that in a large proportion of MDS at least a proportion of the T cells are part of the malignant clone, and that CD3+ cells do not represent an appropriate patient normal control for genome-wide studies. Disclosures: No relevant conflicts of interest to declare.

scholarly journals A Copy Number Variant on Chromosome 20q13.3 Implicated in Thinness and Severe Obesity

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sandra J. Hasstedt ◽  
Yuanpei Xin ◽  
Rong Mao ◽  
Tracey Lewis ◽  
Ted D. Adams ◽  
...  
Keyword(s):  
Copy Number ◽  
Severe Obesity ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Null Alleles ◽  
Comparative Genomic ◽  
Likelihood Analysis ◽  
Severely Obese ◽  
Obese Subjects ◽  
Real Time Qpcr

Background/Objectives.To identify copy number variants (CNVs) which are associated with body mass index (BMI).Subjects/Methods.CNVs were identified using array comparative genomic hybridization (aCGH) on members of pedigrees ascertained through severely obese (BMI ≥ 35 kg/m2) sib pairs (86 pedigrees) and thin (BMI ≤ 23 kg/m2) probands (3 pedigrees). Association was inferred through pleiotropy of BMI with CNVlog⁡2intensity ratio.Results.A 77-kilobase CNV on chromosome 20q13.3, confirmed by real-time qPCR, exhibited deletions in the obese subjects and duplications in the thin subjects (P=2.2×10-6). Further support for the presence of a deletion derived from inference by likelihood analysis of null alleles for SNPs residing in the region.Conclusions.One or more of 7 genes residing in a chromosome 20q13.3 CNV region appears to influence BMI. The strongest candidate isARFRP1, which affects glucose metabolism in mice.

scholarly journals Copy Number Variants in Four Italian Turkey Breeds

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 391
Author(s):  
Maria Giuseppina Strillacci ◽  
Stefano Paolo Marelli ◽  
Raffaella Milanesi ◽  
Luisa Zaniboni ◽  
Chiara Punturiero ◽  
...  
Keyword(s):  
Copy Number ◽  
Genetic Improvement ◽  
Geographical Origin ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Gene Introgression ◽  
Data Set ◽  
Behavioral Traits ◽  
Genomic Level ◽  
History Of

Heritage breeds can be considered a genetic reservoir of genetic variability to be conserved and valorized considering their historical, cultural, and adaptive characteristics and possibly for their high potential in commercial hybrid genetic improvement by gene introgression. The aim of the present research is to investigate via Copy Number Variant (CNVs) the genomic makeup of 4 Italian autochthonous turkey breeds (Bronzato Comune—BrCI, 24; Ermellinato di Rovigo—ErRo, 24; Parma e Piacenza—PrPc, 25; Romagnolo—RoMa, 29). CNVs detection was performed using two different software and an interbreed CNVs comparison was carried out. A total of 1077 CNVs were identified in 102 turkeys, summarized into 519 CNV regions (CNVRs), which resulted after merging in 101 and 18 breed and shared regions. Biodiversity was analyzed using the effective information supplied by CNVs analysis, and BrCI and ErRo were characterized by a low mapped CNV number. Differences were described at a genomic level related to physiological, reproductive, and behavioral traits. The comparison with other three Italian turkey breeds (Brianzolo, Colle Euganei, and Nero Italiano) using a CNV data set available in the literature showed high clustering properties at the genomic level, and their relationships are strictly linked to the geographical origin and to the history of the rural structure of their native regions.

scholarly journals Identification of Copy Number Variants in a Southern Chinese Cohort of Patients with Congenital Scoliosis

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1213
Author(s):  
Wenjing Lai ◽  
Xin Feng ◽  
Ming Yue ◽  
Prudence W.H. Cheung ◽  
Vanessa N.T. Choi ◽  
...  
Keyword(s):  
Copy Number ◽  
Copy Number Variants ◽  
Copy Number Variant ◽  
Congenital Scoliosis ◽  
Sequencing Data ◽  
Rare Cnvs ◽  
Southern Chinese ◽  
Lateral Curvature ◽  
Chinese Cohort ◽  
Family Based

Congenital scoliosis (CS) is a lateral curvature of the spine resulting from congenital vertebral malformations (CVMs) and affects 0.5–1/1000 live births. The copy number variant (CNV) at chromosome 16p11.2 has been implicated in CVMs and recent studies identified a compound heterozygosity of 16p11.2 microdeletion and TBX6 variant/haplotype causing CS in multiple cohorts, which explains about 5–10% of the affected cases. Here, we studied the genetic etiology of CS by analyzing CNVs in a cohort of 67 patients with congenital hemivertebrae and 125 family controls. We employed both candidate gene and family-based approaches to filter CNVs called from whole exome sequencing data. This identified 12 CNVs in four scoliosis-associated genes (TBX6, NOTCH2, DSCAM, and SNTG1) as well as eight recessive and 64 novel rare CNVs in 15 additional genes. Some candidates, such as DHX40, NBPF20, RASA2, and MYSM1, have been found to be associated with syndromes with scoliosis or implicated in bone/spine development. In particular, the Mysm1 mutant mouse showed spinal deformities. Our findings suggest that, in addition to the 16p11.2 microdeletion, other CNVs are potentially important in predisposing to CS.

scholarly journals Gene copy-number polymorphism in nature

2010 ◽  
Vol 277 (1698) ◽  
pp. 3213-3221 ◽  
Author(s):  
Daniel R. Schrider ◽  
Matthew W. Hahn
Keyword(s):  
Natural Selection ◽  
Copy Number Variation ◽  
Copy Number ◽  
Molecular Mechanisms ◽  
Copy Number Variants ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Phenotypic Differences ◽  
Sequencing Technologies ◽  
Number Variation

Differences between individuals in the copy-number of whole genes have been found in every multicellular species examined thus far. Such differences result in unique complements of protein-coding genes in all individuals, and have been shown to underlie adaptive phenotypic differences. Here, we review the evidence for copy-number variants (CNVs), focusing on the methods used to detect them and the molecular mechanisms responsible for generating this type of variation. Although there are multiple technical and computational challenges inherent to these experimental methods, next-generation sequencing technologies are making such experiments accessible in any system with a sequenced genome. We further discuss the connection between copy-number variation within species and copy-number divergence between species, showing that these values are exactly what one would expect from similar comparisons of nucleotide polymorphism and divergence. We conclude by reviewing the growing body of evidence for natural selection on copy-number variants. While it appears that most genic CNVs—especially deletions—are quickly eliminated by selection, there are now multiple studies demonstrating a strong link between copy-number differences at specific genes and phenotypic differences in adaptive traits. We argue that a complete understanding of the molecular basis for adaptive natural selection necessarily includes the study of copy-number variation.

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