An alignment between two DNA sequences maps every nucleotide in one sequence to a nucleotide in another sequence. By making and using whole-genome alignments, the UCSC Genome Browser always allowed users to "lift" genome annotations to another assembly (liftOver), in bulk, one track at a time. QuickLift is a tool that uses the same algorithm, but it maps (liftOver) annotations on demand, in real-time, for all visible tracks. Only the annotations in the currently visible region are lifted, so this is usually fast enough when browsing a genome. For example, QuickLift can be used to map annotations from hg38 or hg19 to any of the hundreds of new human high-quality genomes in GenArk