 Although phycodnaviruses are diverse genetically and infect different hosts, they display high levels of similarity on the structural level to each other and other NCLDVs.Phylogenetic analysis of the major capsid protein within the group indicates great likelihood of close relatedness, as well as prior divergence from a single common ancestor, which is believed to be a small DNA virus.Additionally, studies suggest that genome gigantism, characteristic of all chloroviruses, is a property which evolved early on in the history of NCLDVs, and subsequent adaptations towards respective hosts and particular habitats resulted in mutations and gene loss events, which ultimately shaped all currently existing chlorovirus species.