Genetic recombination of precociousness and anticoccidial drug resistance in Eimeria tenella.

Two strains of Eimeria tenella differing in decoquinate-resistance and developmental rate were crossed. Strain Wis-F was decoquinate-sensitive (DS) and precocious (P+), while strain 368 was decoquinate-resistant (DR) and had a normal developmental rate (P-). Cultures of the parent strains and a culture derived from a mixture of parent strain oocysts were propagated through drug and developmental barriers to select parasites with the respective parental phenotypes (DS/P + and DR/P-) and the recombinant phenotype (DR/P+). The ability of a portion of the population in the strain-cross culture to reproduce in the presence of simultaneously imposed drug and developmental barrier showed that they were the recombinant phenotype (DR/P+), which had been produced through fertilization by gametes of opposite parent strains of E. tenella.