FIG 2.

Examples of orthologous and polymorphic ERV loci in perissodactyls. The DNA sequences of the extreme 5′ and 3′ ends of orthologous ERV internal genes are shown enclosed by red boxes (with the majority of intervening ERV sequence being omitted). Target site duplication (TSD) sequences flanking ERV insertions are shown enclosed by blue boxes. Regions (20 to 30 bp) of upstream and downstream flanking genomic DNA sequence are shown for each locus. (a) Examples of insertions belonging to the Theta, Rho, and Sigma lineages that occur at orthologous loci in the horse, donkey, and rhinoceros genomes. (b) Examples of the ERVs in EqERV.b1 and EqERV.U1 lineages that are polymorphic within horses.