In vitro virus is a molecular construct for in vitro protein evolution, which requires some mechanism to link phenotype to genotype. The first in vitro virus was realized by bonding a nascent protein with its coding mRNA via puromycin in in vitro translation. We report a new construct of in vitro DNA virus. The virion was a covalent cDNA–protein fusion, and virion formation did not require any modification of mRNA. Due to intactness of mRNA, this type of in vitro DNA virus will take the next step toward in vitro autonomous evolution, just like in vivo viral evolution in a cellstat.
