Genotype calls & imputation - Genomics
DescriptionGenotype calls (based on genotyping array measurements) and imputed values. All values are on the +/forward strand.
The UKB download format uses 1-byte to store each person/snp Call value. Around 500GB of storage would be required to download the entire Calls data on 500,000 participants.
Imputed data is delivered in bgen format, and around 5TB of storage would be required to download the entire imputed data on 500,000 participants (the imputed dataset on the first 150,000 participants is just under 1.5TB). The information scores that correspond to the quality measure of the imputed genotypes have been computed with QCTOOL and can be downloaded from the Resources tab on a per Chromosome basis as part of the Imputed minor allele frequencies datasets.
Researchers who need only a few specific SNPs (rather than the whole-chromosome datasets below) should list these SNP IDs on the "free-text" option section of their Application and a custom dataset will be created for them (please state whether the loci are listed as rsID or Affymetrix ID values.)
Researchers are strongly advised to read the Resource "Genotype imputation and genetic association studies using UK Biobank data" before performing any analyses using the imputed data. Questions about using the imputed genotypes can be directed to a special UK Biobank mailing list, which can be joined at https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=UKB-GENETICS.
Please note that imputation results for Chromosome X are not yet available.