Visualization of linear AC constructs by fiber-FISH using pLL-EHC (green) and telomeric DNA (red), as probes. The two arrows of the same color in the four different images (A, B, C, and D) point to the two telomeric signals on the same AC constructs. Arrowheads point to some of the non-recombined circular pLL-EHC molecules. Note: the variability in size of the observed linear and circular DNA molecules is caused by non-uniform extension of the DNA molecules. Bars = 10 μm.