FIG. 2.

Alignment of the 928-nt pro-pol fragments from published full-length PERV γ1 clones. Designation of the env gene to PERV A, B, and C subfamilies was carried out by sequence comparison to Y12238, Y12239, and AF038600, respectively (in the column labeled env gene). The classification of the pro-pol fragment to γ1A, γ1B, and γ1C is shown in the column labeled pro-pol gene. The polymorphic nucleotides (n = 144; 15.4%) are depicted with the numbers of their positions in the alignment of the data set shown at the top. The 51 nucleotide positions whose sequence invariably determined the pro-pol subfamilies γ1B and γ1C are shown in bold. Mutant nucleotides are depicted in shaded boxes. pro-pol fragments harboring an ORF are indicated with an asterisk.