In a complementation test involving 4 monogenic recessive mutants with the same
ID: 95264 • Letter: I
Question
In a complementation test involving 4 monogenic recessive mutants with the same phenotype, a, b, c, and d, only these two crosses: a X b and c X d produce the F1 progeny that do not resemble wild type, while all other crosses do. What conclusion is correct? A. These mutants represent only one gene B. These mutants represent 2 genes C. These mutants represent 3 genes D these mutants represent 4 genes E. The information is not sufficient to draw a conclusion. In a complementation test involving 4 monogenic recessive mutants with the same phenotype, a, b, c, and d, only these two crosses: a X b and c X d produce the F1 progeny that do not resemble wild type, while all other crosses do. What conclusion is correct? A. These mutants represent only one gene B. These mutants represent 2 genes C. These mutants represent 3 genes D these mutants represent 4 genes E. The information is not sufficient to draw a conclusion. A. These mutants represent only one gene B. These mutants represent 2 genes C. These mutants represent 3 genes D these mutants represent 4 genes E. The information is not sufficient to draw a conclusion.Explanation / Answer
Correct option is - B. These mutants represent 2 genes
Because in complementation test, if two strains of an organism with different homozygous recessive mutations produce offspring with the wild-type phenotype, it indicates that complementation will occur and the mutations are in different genes. But if the offspring will not produce the wild-type phenotype, it indicates that complementation will not occur and mutations occur in same gene.
As here in two cross - a X b and c X d does not produce wild type progeny, it indicates a & b rely on same gene and c & d also rely on another same gene. Thus mutants represent 2 genes.