Identification of a point mutation in the para-type sodium channel gene from a pyrethroid-resistant cattle tick

To investigate the molecular mechanism of resistance to pyrethroids in the southern cattle tick, Boophilus microplus, we have obtained and sequenced a partial para-homologous sodium channel cDNA from susceptible and pyrethroi d-resistant tick strains. A point mutation that results in an amino acid ch ange from Phe to lie was identified in the highly conserved domain IIIS6 of the homologous sodium channel from ticks that are highly resistant to pyre throid acaricides, This mutation is at a location different from those repo rted in the same gene in pyrethroid-resistant insects, (C) 1999 Academic Pr ess.