An article1 by P.J. Hastings and colleagues corroborates our observations that a substantial fraction of amplifications occur as TIDs.
1. Lin D, Gibson IB, Moore JM, Thornton PC, Leal SM, Hastings PJ. 2011. Global chromosomal structural instability in a subpopulation of starving Escherichia coli cells. PLoS Genet 7: e1002223 -- Eric Kofoid