The latest genome to be sequenced is that of the parasite responsible for Lyme disease —Borrelia burgdorferi. Why should this sequence be of interest? First, because Lyme disease is the most common vector-borne disease in Europe, the United States and parts of Asia, so the more we know about the parasite that causes it, the closer we should be to possible treatments. Second, because this is the first spirochaete genome to be sequenced, and the first prokaryotic genome to contain several genetic elements.