Fig. 4.

Patterns of dynamic mosaicism and karyotype evolution in a dicentric ring chromosome 18. a/b: Karyotype showing a dicentric ring chromosome 18 and variant ring chromosomes 18. c/d: FISH images showing absence of subtelomeric signals in the dicentric ring chromosome 18 and variant tricentri and tetracentric rings (in inset). e: FISH image showing absence of BCL2 locus in the ring chromosome (paint ring chromosome 18 in inset). f: a diagram showing dynamic mosaicism induced by sister chromatid exchange (SCE). Likely unstable monocentric ring 18 was not seen by karyotyping and FISH. Dicentric ring chromosome 18 was seen in 91% of cells and variants of tri−/tetra-centric ring chromosomes 18 and ring loss was seen in 9% of cells