Variant calling across 505 openly consented samples from four Gambian populations on GRCh38

The International Genome Sample Resource (IGSR) repository was established to maximise the utility of human genetic data derived from openly consented samples within the research community. Here we describe variant detection in 505 samples from four populations in The Gambia, using the GRCh38 reference genome, adding to the range of populations for which this has been done and, importantly, making allele frequencies available. A multi-caller site discovery process was applied along with imputation and phasing to produce a phased biallelic single nucleotide variant (SNV) and insertion/deletion (INDEL) call set. Variation had not previously been explored on the GRCh38 human genome assembly for 387 of the samples. Compared to our previous work with the 1000 Genomes Project data on GRCh38, we identified over nine million novel SNVs and over 870 thousand novel INDELs.