http://polymer.bu.edu/ogaf/html/chp51.htm
The link above shows that the make-up of the growth media plays a key role in controlling the growth pattern on the surface of an agar plate. I doubt that 2 near clones of anthrax spores would produce different growth patterns without also displaying very apparent genetic differences readily seen with DNA analysis.
Thanks for the ping.
This is just in time to get another delay in the lawsuits.
The minimum possible information was leaked. They didn't give a clue as to what type of characteristic distinguishes the two populations that were mixed.
By the way, a leak on the July 4 holiday is a bit strange. I guess somebody wants to get the minimum possible public exposure.