Barbara McClintock examined the mechanism for the appearance of purple spots in the kernels of yellow and white corn. She attributed the spots to: A new type of fungus Insertion of a genetic element into the Pr allele of heterozygous corn (Prpr) Insertion of a genetic element into the CI allele of heterozygous corn (CIC) Insertion of a genetic element into the pr allele of heterozygous corn (Prpr) Insertion of a genetic element into the C allele of heterozygous corn (CIC)