RT Journal Article SR Electronic T1 The rate of false polymorphisms introduced when imputing genotypes from global imputation panels JF bioRxiv FD Cold Spring Harbor Laboratory SP 080770 DO 10.1101/080770 A1 Ida Surakka A1 Antti-Pekka Sarin A1 Sanni E Ruotsalainen A1 Richard Durbin A1 Veikko Salomaa A1 Mark J Daly A1 Aarno Palotie A1 Samuli Ripatti A1 SISu project group YR 2016 UL http://biorxiv.org/content/early/2016/10/13/080770.abstract AB Previous studies1,2 have shown that large multi-population imputation reference panels increases the number of well-imputed variants. However, to our knowledge, no previous studies have evaluated the rate of introduced variation in monomorphic sites of the study population when using imputation panels with admixed populations. In this study we evaluate the rate of false positive variants introduced by the imputation of Finnish genotype data using global reference panels (Haplotype Reference Consortium1; HRC, and the 1000Genomes project Phase I3; 1000G) and compare the results to a Finnish population-specific reference panel combining whole genome and exome sequenced samples. In sites that were monomorphic in our test set, we observed high false positive rates for the global reference panels (4.0% for 1000G and 2.6% for HRC) compared to the Finnish panel (0.26%). This rate was even higher (7.4%) when using a combination panel of 1000G and Finnish whole genome sequences with cross-panel imputation.