The largest virus known is Mimivirus. It was discovered in 2003 and is notable for its size and complexity. Mimivirus has a diameter of around 400 nanometers, which is larger than some bacteria. Its genome is also incredibly large, containing over 1.2 million base pairs. This is significantly larger than the genomes of most viruses.
Mimivirus has sparked debate about the definition of life and the origins of viruses. Some scientists believe that its large size and complex genome suggest that it may be an evolutionary bridge between nonliving viruses and living organisms. Others argue that it is simply an anomaly, a result of extreme evolution in a specific lineage.
While Mimivirus is the largest known virus by size and genome size, other giant viruses also exist, such as Megavirus chilensis, which has a genome of 1,259,197 base pairs. These giant viruses are challenging our understanding of the boundaries between viruses and other forms of life.
