False-colour transmission electron micrograph of virus particles of the papilloma virus, or wart virus, which belongs to the papovavirus class. Papilloma viruses cause warts to grow on the hands & feet as well as on the mucous membranes in the mouth, & on the genitals. Individual virions have icosahedral capsid symmetry (35-45 nanometres across) & do not possess a lipoprotein envelope. Genetic information is in the form of double- stranded DNA contained within the protein capsid. Nearly all members of the group are oncogenic or capable of producing tumours. Magnification: x56,000 at 6x4.5cm size, x36,000 at 35mm size.