Fig. 4

Fluorescence in situ hybridisation (FISH) performed on metaphase chromosomes harbouring the t(7;12)(q36;p13). a FISH using a three colour approach enables the detection of both normal chromosomes 7 (harbouring only blue hybridisation signals) and 12 (harbouring green and orange fluorescent signals) and their derivatives (green signals on the der(7) and blue and orange signals on the der(12)). The DAPI counterstaining of the chromosomes has been converted into grey scale to simulate a G-banding pattern (figure taken from Naiel et al., 2013 [17]). b Schematic representation showing localisation and colour-code of the FISH probes relative to the three colour probe set used. c FISH using a two colour approach enables the detection of both normal chromosomes 7 (harbouring only orange hybridisation signals) and 12 (harbouring only green fluorescent signals) and their derivatives carrying orange and green fusion signals. d Schematic representation showing localisation and colour-code of the FISH probes relative to the two colour probe set used. It should be noted that the two colour set does not allow to discriminate between the two derivatives based on colour pattern only. The size and morphology of chromosomes 7 and 12 compared to their respective derivatives are very similar, making the identification of the rearrangement difficult without the aid of FISH. Both probe sets have been provided by MetaSystems Gmbh, Altlussheim, Germany