Relationships of human polyoma JC virus (JCV) subtypes found in humans from different parts of the world . Letters refer to individual subtypes. (a) The hypothesized pattern of spread of JCV subtypes through the world (excluding the Americas); (b) an inferred phylogeny of JCV subtypes, assuming an African origin for the virus. Adapted from .
Disotell Genome Biology 2003 4:213 doi:10.1186/gb-2003-4-5-213