Meet the giants among viruses
The list of these mega-sized entities continues to grow
SUPERSIZE ME The more scientists look, the more giant viruses pop up. The viral behemoths, which largely infect amoebas, may be common worldwide.
Clockwise from top left: P. Colson; J. Andreani et al/J. of Virology 2017; © IGS CNRS, Aix-Marseille Univ.; Chantal Abergel and Jean-Michel Claverie
For decades, the name “virus” meant small and simple. Not anymore. Meet the giants.
Today, scientists are finding ever bigger viruses that pack impressive amounts of genetic material. The era of the giant virus began in 2003 with the discovery of the first Mimivirus (SN: 5/23/09, p. 9). The viral titan is about 750 nanometers across with a genetic pantry boasting around 1.2 million base pairs of DNA, the information-toting bits often represented with A, T, C and G. Influenza A, for example, is roughly 100 nanometers across with only about 13,500 base pairs of genetic material.
In 2009, another giant virus called Marseillevirus was identified. It is different enough from mimiviruses to earn its own family. Since 2013, mega-sized viruses falling into another eight potential virus families have been found,
