Age of Base
From the calculated ancestral sequences, we infer the age of a base, i.e. the timing of the most recent mutation for each base of the genome. Each position of the genome is compared to its immediate inferred ancestor, then its ancestor, etc. until a difference is found. The inferred substitution event therefore occurred on a specific branch of the tree, which is identified by all the extant species which eventually descended from that branch, as illustrated below.
This track is currently only available for the human genome.