Are there duplicate samples in the Illumina iControlDB?
Samples are checked for duplicate barcode numbers, and duplicates are not allowed. This does not prevent the same sample from being run on different barcodes. There is not a check performed at the genotype level to ensure unique samples. Additionally, different sources may have run the same commercially available sources of DNA and submitted the data. Therefore, we recommend performing genotype-level comparison of the data that you are downloading prior to analysis to ensure the most accurate frequency information for your study.