sequence role denotes denotes background genome reference genomic background Being a 'genomic background' implies that a variant genotype was derived from this background (which is the case for most model organism database genotypes/strains). This is a subtly different notion than being a 'reference genotype' , which can be any genotype that serves as a basis for comparison. But in a sense all background genotypes are by default reference genotypes, in that the derived variant genotype is compared against it. background genotype A genomic genotype that specifies the baseline sequence of a genome from which a variant genome is derived (through the introduction of sequence alterations). genomic genotype