ATCGCGATBEERCATKETCHUPCCATACTCATTAG                       edit at 8
ATCGCGATBEEBEERRCAKETCHUPTKETCHUPCCATACTCATTAG            then 12
ATCGCGATBEEBEERRCABEERKETKETCHUPCHUPTKETCHUPCCATACTCATTAG then 18
        ???^^^^?  ^^^^???vvvvvvv?????vvvvvvv