In the Arabidopsis lineage, an ancestral helitron containing transcription factor binding motifs (TFBMs) for the PHE1 MADS-box transcription factor transposed into the promoter regions of other genes, transferring the TFBM and bringing those genes under the regulatory control of PHE1 [35]. In mammals, the mouse ancestral genome, after divergence from the rat lineage, acquired an LTR retrotransposon harboring three TFBMs in the LTR region recognized by Cdx2/Eomes/Elf5. This LTR family, RLTR13D5, became activated during mouse lineage evolution and subsequently distributed the three TFBMs into multiple locations, recruiting lineage-specific targets into the placental regulatory network [33]. In the anthropoid primate lineage, a different LTR family, THE1B, became amplified and plays a regulatory role for a suite of downstream genes. Noticeably, the LTR edge of one THE1B member joined with local genomic sequences and gave rise to a DLX3 binding motif, which is recognized by DLX3 and activates the key placental gene CRH in primates [34].