Eco Rl comes from e.co//, strain R. Eco Rl recognises dyad (mirror) sequences. Dimers sit on both strands of DNA simultaneously. Recognition site for Eco Rl is 5−G−A−A−T−T−C−33−C−T−T−A−A−G−5 This DNA sequence is the six base sequence recognised by the restriction enzyme Eco Rl.