scholarly journals Identification of Copy Number Variation in Domestic Chicken Using Whole-Genome Sequencing Reveals Evidence of Selection in the Genome

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 809
Author(s):  
Donghyeok Seol ◽  
Byung June Ko ◽  
Bongsang Kim ◽  
Han-Ha Chai ◽  
Dajeong Lim ◽  
...  

Copy number variation (CNV) has great significance both functionally and evolutionally. Various CNV studies are in progress to find the cause of human disease and to understand the population structure of livestock. Recent advances in next-generation sequencing (NGS) technology have made CNV detection more reliable and accurate at whole-genome level. However, there is a lack of CNV studies on chickens using NGS. Therefore, we obtained whole-genome sequencing data of 65 chickens including Red Jungle Fowl, Cornish (broiler), Rhode Island Red (hybrid), and White Leghorn (layer) from the public databases for CNV region (CNVR) detection. Using CNVnator, a read-depth based software, a total of 663 domesticated-specific CNVRs were identified across autosomes. Gene ontology analysis of genes annotated in CNVRs showed that mainly enriched terms involved in organ development, metabolism, and immune regulation. Population analysis revealed that CN and RIR are closer to each other than WL, and many genes (LOC772271, OR52R1, RD3, ADH6, TLR2B, PRSS2, TPK1, POPDC3, etc.) with different copy numbers between breeds found. In conclusion, this study has helped to understand the genetic characteristics of domestic chickens at CNV level, which may provide useful information for the development of breeding systems in chickens.

2016 ◽  
Author(s):  
Ryan L. Collins ◽  
Matthew R. Stone ◽  
Harrison Brand ◽  
Joseph T. Glessner ◽  
Michael E. Talkowski

AbstractSummaryCopy number variation (CNV) is a major component of structural differences between individual genomes. The recent emergence of population-scale whole-genome sequencing (WGS) datasets has enabled genome-wide CNV delineation. However, molecular validation at this scale is impractical, so visualization is an invaluable preliminary screening approach when evaluating CNVs. Standardized tools for visualization of CNVs in large WGS datasets are therefore in wide demand.Methods & ResultsTo address this demand, we developed a software tool, CNView, for normalized visualization, statistical scoring, and annotation of CNVs from population-scale WGS datasets. CNView surmounts challenges of sequencing depth variability between individual libraries by locally adapting to cohort-wide variance in sequencing uniformity at any locus. Importantly, CNView is broadly extensible to any reference genome assembly and most current WGS data types.Availability and ImplementationCNView is written in R, is supported on OS X, MS Windows, and Linux, and is freely distributed under the MIT license. Source code and documentation are available from https://github.com/RCollins13/[email protected]


2020 ◽  
Author(s):  
Yuan yuan Lei ◽  
Guo chao Zhang ◽  
Chao qi Zhang ◽  
li yan xue ◽  
Zhen lin Yang ◽  
...  

Abstract Background: Genomic instability plays a large role in the process of cancer. Tumor mutational burden (TMB) is closely related to immunotherapy outcome and is an important manifestation of genomic instability. However, the cost of TMB detection is extremely high, which limits the use of TMB in clinical practice. Another new indicator of genome instability, CNVA (the average copy number variation) which calculates the changes of 0.5 Mb chromosomal fragments, requires extremely low sequencing depth, and is expected to replace TMB as a new marker of immune efficacy.Methods: A total of 50 samples (23 of which came from patients who received immunotherapy) were subjected to low-depth (10X) chromosome sequencing on the MGI platform. CNVA was calculated by the formula avg (abs (copy number-2)). Then, we analyzed the relationship between CNVA and immune infiltration or immunotherapy efficacy. In addition, through the analysis of whole genome sequencing data of 509 lung adenocarcinoma in the TCGA database, we compared CNVA with classic marker TMB to evaluate the value of CNVA as an immune evaluation index.Results: Compared with the low CNVA group, the high CNVA group had higher expression of PD-L1, CD39 and CD19, and more infiltration of CD8 + T cells and CD3 + T cells. Among the 23 patients treated with immunotherapy, the average CNVA value of the SD (stable disease)/PR (partial response) group was higher than that of the PD (progressive disease) group (P <0.05). The data of whole genome sequencing data of 509 lung adenocarcinomas from TCGA and real-time quantitative PCR results of 22 frozen specimens found that CNVA was more correlated with CD8 and PD-L1 than TMB. In addition, CNVA showed a specific positive correlation with TMB (r = 0.2728, p < 0.0001).Conclusion: CNVA can be a good indicator of immune infiltration and predicting immunotherapy efficacy. With its low cost and potential clinical application for testing, it is expected to become a substitute for TMB.


BMC Genomics ◽  
2012 ◽  
Vol 13 (Suppl 6) ◽  
pp. S16 ◽  
Author(s):  
Angel Janevski ◽  
Vinay Varadan ◽  
Sitharthan Kamalakaran ◽  
Nilanjana Banerjee ◽  
Nevenka Dimitrova

BMC Genomics ◽  
2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Aitor Serres-Armero ◽  
Inna S. Povolotskaya ◽  
Javier Quilez ◽  
Oscar Ramirez ◽  
Gabriel Santpere ◽  
...  

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