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Porcine cirvorirus (PCV) is a non-cytophatogenic non-enveloped virus with icosahedral symmetry and a single-stranded circular DNA as genome1 that codes for the capsid protein (cap gene in ORF2) and repli-case (rep gene in ORF1)2. Type 1 porcine circovirus (PCV1) is classically associated to permanent infec-tions in PK-15 while type 2 (PCV2) might have a role on some diseases of the swine such as post-weaning multi-systemic wasting syndrome and reproductive failures3. Currently, little is known on the genetic stability of PCV2 in vitro, mainly due to the tricky nature of PCV2 isolation in cell culture and the need for im-mune reagents for the confirmation of virus isolation. The aim of this investigation was to assess the ge-netic divergence of PCV2 after low passage in VERO and SK-RST cell lines and to suggest the detection of evolutionary signal as a tool for the confirmation of virus isolation. Two pools (12-04 and 17-04) of spleen/liver / lymph nodes from two different adult swine collected at a slaughterhouse, previously positive for PCV24 were used for cell culture isolation. The pools were prepared as 20 % suspensions (w/v) in TE buffer (10 mMTris– HCl, 1 mM EDTA, pH 8.0) and stored at-80 ºC. The Cap gene of porcine circovirus type 2 (PCV2) evolves by positive selection in vitro O gene Cap de circovírus suíno tipo 2 (PCV2) evolui por seleção positiva in vitr