Phylogenetic relationships between modern and ancient M. leprae. A maximum likelihood tree describing the relationship between Sk14, Sk27 and other ancient (in bold) and modern M. leprae genomes . Locations and dates (14C estimates or year of isolation) are given in brackets. Groupings are derived from Schuenemann et al. . The position of Sk27 is poorly defined but is clearly within group 2 and closely related to other ancient genomes.