▁the ▁similar ities ▁of ▁the ▁different ▁families ▁of ▁this ▁group ▁have ▁a ▁common ▁vir al ▁ancest or . ▁One ▁feature ▁of ▁this ▁group ▁is ▁a ▁large ▁gen ome ▁and ▁the ▁presence ▁of ▁many ▁gen es ▁involved ▁in ▁DNA ▁repair , ▁DNA ▁rep lication , ▁trans cription , ▁and ▁translation . ▁Typ ically , ▁vir uses ▁with ▁smaller ▁genom es ▁do ▁not ▁contain ▁gen es ▁for ▁these ▁processes . ▁Most ▁of ▁the ▁vir uses ▁in ▁this ▁family ▁also ▁rep licate ▁in ▁both ▁the ▁host ' s ▁nucle us ▁and ▁cy top las m , ▁thus ▁the ▁name ▁nucle ocy top las mic . ▁ ▁There ▁are ▁ 4 7 ▁N CL D V ▁core ▁gen es ▁currently ▁recogn ised . ▁These ▁include ▁four ▁key ▁prote ins ▁involved ▁in ▁DNA ▁rep lication ▁and ▁repair : ▁the ▁en zym es ▁DNA ▁polym er ase ▁family ▁B , ▁the ▁to pois omer ase ▁II ▁A , ▁the ▁F L AP ▁end on uc lease ▁and ▁the ▁processing ▁factor ▁pro l ifer ating ▁cell ▁nuclear ▁ant igen . ▁Other ▁prote ins ▁include ▁DNA ▁dependent ▁R NA ▁polym er ase ▁II ▁and ▁trans cription ▁factor ▁II ▁B . ▁ ▁As cov ir idae ▁M embers ▁of ▁the ▁family ▁As cov ir idae ▁come ▁in ▁different ▁shapes . ▁Some ▁can ▁be ▁rod - sh aped , ▁while ▁others ▁are ▁o val . ▁They ▁measure ▁up ▁to ▁ 1 3 0   nm ▁wide ▁and ▁ 4 0 0   nm ▁long . ▁Th eses ▁vir uses ▁have ▁circular ▁double ▁str