Fig. 5.

Chimeric L1-BovB element in cattle genomes. a Chimeric L1-BovB retrotransposon found in cattle genomes (Bos taurus and Bos indicus). L1-BT and BovB correspond to RepBase names [20], representing repeats which are known to have been recently active. The orange bar is the length of the entire ORF. b Kimura divergence plot of BovB and L1 elements in Bos taurus. RepeatMasker [54] was used to mask all BovB and L1 nucleotide sequences in the cow genome and calculate divergence from alignments to RepBase [20] consensus sequences. The y-axis represents coverage against the RepBase super consensus library; the x-axis indicates the Kimura divergence estimate. Ruminants are the only mammals which have currently active lineages of both BovB and L1 elements, explaining how the chimeric BovB-L1 element may have arisen. RVT_1 reverse transcriptase, EN endonuclease domain