Distinctive differences in long terminal repeat sequences between γ1 endogenous retroviruses of African and Eurasian suid species.

Diversity of long terminal repeats (LTRs) from γ1 endogenous retroviruses (ERVs) was analysed by DNA sequencing in 10 species of the family Suidae (suids, pigs and hogs). Phylogenetic analysis separated LTR sequences into two groups which correlated approximately with either the previously described cluster I and III, or the clusters II, IV and V. Interestingly, a specific LTR exhibiting a novel molecular rearrangement was identified exclusively within African host species when compared to LTRs previously reported from known ERVs in the domestic pig (Sus scrofa). Furthermore, other sections of LTRs appear to be unique to African suids as suggested by phylogenetic analysis. These differences between African and Eurasian ERV lineages show that these ERVs belong to different viral sub-populations, implying coevolution of endogenous viral sequences with their host species and providing no evidence of transfer of viral sequences between African and Eurasian suids.