Figure 8.

GPY/F module comparisons. Based on the GPY/F module, Retroviridae class I appears to be more similar to Ty3/Gypsy LTR retroelements of plants and fungi than other Retroviridae classes. A) Multiple alignment of gammaretroviruses (class I) and chromoviruses. B) Between gammaretroviruses and Athila/Tat elements. C) Between gammaretroviruses and Retroviridae class II, this alignment reveals important differences between the two classes, as well as the evolutionary transition of the canonical GPY/F motif towards other motif states. D) Based on the GPY/F module, spumaretroviruses (class III) is similar to class I, but also to Ty3/Gypsy errantiviruses. In fact, both spumaretroviral and errantiviral modules lost the canonical motif during evolution.