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Open Access Highly Accessed Research article

Copy number variations (CNVs) identified in Korean individuals

Tae-Wook Kang1, Yeo-Jin Jeon1, Eunsu Jang2, Hee-Jin Kim1, Jeong-Hwan Kim1, Jong-Lyul Park1, Siwoo Lee2, Yong Sung Kim1, Jong Yeol Kim2* and Seon-Young Kim1*

Author Affiliations

1 Medical Genomics Research Center, KRIBB, 52 Eoeun-dong, Yuseong-gu, Daejeon 305-806, Republic of Korea

2 Department of Medical Research, KIOM, 483 Expo-ro, Yuseong-gu, Daejeon 305-811, Republic of Korea

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BMC Genomics 2008, 9:492  doi:10.1186/1471-2164-9-492

Published: 18 October 2008

Abstract

Background

Copy number variations (CNVs) are deletions, insertions, duplications, and more complex variations ranging from 1 kb to sub-microscopic sizes. Recent advances in array technologies have enabled researchers to identify a number of CNVs from normal individuals. However, the identification of new CNVs has not yet reached saturation, and more CNVs from diverse populations remain to be discovered.

Results

We identified 65 copy number variation regions (CNVRs) in 116 normal Korean individuals by analyzing Affymetrix 250 K Nsp whole-genome SNP data. Ten of these CNVRs were novel and not present in the Database of Genomic Variants (DGV). To increase the specificity of CNV detection, three algorithms, CNAG, dChip and GEMCA, were applied to the data set, and only those regions recognized at least by two algorithms were identified as CNVs. Most CNVRs identified in the Korean population were rare (<1%), occurring just once among the 116 individuals. When CNVs from the Korean population were compared with CNVs from the three HapMap ethnic groups, African, European, and Asian; our Korean population showed the highest degree of overlap with the Asian population, as expected. However, the overlap was less than 40%, implying that more CNVs remain to be discovered from the Asian population as well as from other populations. Genes in the novel CNVRs from the Korean population were enriched for genes involved in regulation and development processes.

Conclusion

CNVs are recently-recognized structural variations among individuals, and more CNVs need to be identified from diverse populations. Until now, CNVs from Asian populations have been studied less than those from European or American populations. In this regard, our study of CNVs from the Korean population will contribute to the full cataloguing of structural variation among diverse human populations.