treat N as N in reverse complement
treat N as N in reverse complement

addgene/giraffe,addgene/giraffe,BjornFJohansson/giraffe,addgene/giraffe,BjornFJohansson/giraffe,UndeadBlow/giraffe,addgene/giraffe,BjornFJohansson/giraffe,BjornFJohansson/giraffe,BjornFJohansson/giraffe,UndeadBlow/giraffe