Scientists were examining the maize genome. They had two specimens: one control and one specimen that had undergone mutagenesis. They saw that the mutant specimen underwent a knockout caused by a nucleotide exchange in the DNA. When they compared gene sequences, they saw same number of nucleotide bases. Which type of mutation had most likely occurred?

Cold case files recently began re-investigating an old murder case. the murder took place in the park; a young man, james, was hit over the head with a brick and killed. police suspected the jealous former boyfriend of james' wife, karen. whoever killed james may have washed their hands in a near-by bird bath as detectives found blood in the bird bath. since the murder took place before dna fingerprinting was available, the suspected killer, ronnie, went free. detectives are now reviewing the blood evidence using dna fingerprinting. based on the dna fingerprints of all possible suspects, who is james' killer?