Cloning and sequencing of a putative acetylcholinesterase cDNA from Boophilus microplus (Acari : Ixodidae)

Using a strategy based on degenerate primers derived from acetylcholinester ase (AChE) from other species, we cloned and sequenced a putative, AChE cDN A from the southern cattle tick. Boophilus microplus (Canestrini). The sequ ence has a high degree of homology to sequences of AChE from ether species reported in the GenBank. The open reading frame of 1,689 bp, corresponding to a deduced sequence of 563 amino acids, has conserved regions and feature s shared by the AChE family, necessary for its catalytic activity. No diffe rences were found in the putative cDNA sequences from organophosphorus acar icide (OP) resistant and susceptible strains. The results suggest that this putative AChE gene is not involved in resistance to OP compounds as a muta ted gene in the resistant strain studied. However, differences were detecte d, with a probe derived from this cDNA, in DNA fragments after digestion of genomic DNA from different strains with restriction nucleases. This indica tes polymorphism in this gene in B. microplus.