Let's face it. Crispr was evolved by bacterial cells in the grip of a phage virus invader. It had to act with enormous speed to try to get ahead of the virus's

Let's face it. Crispr was evolved by bacterial cells in the grip of a phage virus invader. It had to act with enormous speed to try to get ahead of the virus's high speed reproduction machinery and spread the word to successor generations - if any. Fidelity was sacrificed to make an RNA threshing machine and even then it lost more often than it won against the phage. The winners trapped those palindromically patterned bits and lived to breed another day - maybe.