Fig. 8

An example of a random access process on compressed genotypes where the number of alternate alleles is one and the blocks are transformed using bit plane binarization and sorted in row direction. A user needs the genotypes of all samples on chromosome 2 at loci 1000 through 1100, represented by “chr2:1000-1100”. First, GVC finds the blocks containing the required genotype information using a block lookup process. The bitstreams of the selected block, in this case the block with ID 1, are then decoded, yielding the sort indices \({\tilde{a}}\) and the binary matrix \(\mathcal {B}\). Using the position information of each variant site, GVC selects certain rows or columns of the binary matrix \(\mathcal {B}\) and based on the sort index \({\tilde{a}}\). Finally, the selected rows and columns of the binary matrix \(\mathcal {B}\) are then inverse transformed to return the genotypes of all samples at loci 1000 through 1100