SUMMARYThe relative fecundity of populations ofEimeria tenellawas estimated by means of mixed infection using electrophoretic variation of glucose-phosphate isomerases (GPIs) as a genetic marker. A decoquinate-resistant strain with GPI-9 isozyme (DR-NIAH), a decoquinate-sensitive one with GPI-1 (DS-Iwate), and three decoquinate-resistant lines (No. 3, 4, and 5) derived from cross-fertilization between DR-NIAH and DS-Iwate, were used. The GPI phenotypes of the No. 3 and No. 4 lines are GPI-9, and that of No. 5 is GPI-1. Mixed infection experiments were performed between DR-NIAH and DS-Iwate, No. 3 and No. 5, and No. 4 and No. 5. DR-NIAH was predominant over DS-Iwate in the mixed infection, whereas, in single infections, the total oocyst output of DR-NIAH was similar to or less than that of DS-Iwate. Among three lines, No. 4 was predominant over No. 5, and No. 5 was predominant over No. 3 in the mixed infection. Relative fecundity between No. 3 and No. 5 and their patterns of oocyst output in single infections were similar to those in the mixed infection. In contrast, No. 5 produced more oocysts than No. 4 in single infections, suggesting that the oocyst production in the mixed infection may be influenced by the mutual interference or competition between the populations ofE. tenellain the chicken caeca.
Linkage of one component of the major urinary protein complex of mice to the brown coat color locus
