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bioRxiv · 10.1101/356667

EnsembleCNV: An ensemble machine learning algorithm to identify and genotype copy number variation using SNP array data

Abstract

The associations between diseases/traits and copy number variants (CNVs) have not been systematically investigated in genome-wide association studies (GWASs), primarily due to a lack of robust and accurate tools for CNV genotyping. Herein, we propose a novel ensemble learning framework, ensembleCNV, to detect and genotype CNVs using single nucleotide polymorphism (SNP) array data. EnsembleCNV a) identifies and eliminates batch effects at raw data level; b) assembles individual CNV calls into CNV regions (CNVRs) from multiple existing callers with complementary strengths by a heuristic algorithm; c) re-genotypes each CNVR with local likelihood model adjusted by global information across multiple CNVRs; d) refines CNVR boundaries by local correlation structure in copy number intensities; e) provides direct CNV genotyping accompanied with confidence score, directly accessible for downstream quality control and association analysis. Benchmarked on two large datasets, ensembleCNV outperformed competing methods and achieved a high call rate (93.3%) and reproducibility (98.6%), while concurrently achieving high sensitivity by capturing 85% of common CNVs documented in the 1000 Genomes Project. Given this CNV call rate and accuracy, which are comparable to SNP genotyping, we suggest ensembleCNV holds significant promise for performing genome-wide CNV association studies and investigating how CNVs predispose to human diseases.

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Zhang, Z., Cheng, H., Hong, X., Di Narzo, A. F., Franzen, O., Peng, S., Ruusalepp, A., Kovacic, J. C., Bjorkegren, J. L., Wang, X., Hao, K.. 2018-06-27. EnsembleCNV: An ensemble machine learning algorithm to identify and genotype copy number variation using SNP array data. https://doi.org/10.1101/356667

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