Agreed. Not difficult at all when starting with a clonal population. But DNA sequences of both progenitor and progeny had to be obtained for the comparison.
A quick google search leads me to believe that the DNA of all twelve strains of E. Coli have sequenced for quite a while now.
"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence". John Adams
"A dishonest man can always be trusted to be dishonest". Captain Jack Sparrow
