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.
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This track is currently only available for the human genome.