Reciprocal Translocation Analysis with Whole Chromosome Painting for FISH

Ionizing radiation can produce many chromosome aberrations; however, a number of aberrations are not readily detectable with a conventional Giemsa staining and require special staining methods. Moreover, an easy method to identify nondetectable chromosomal aberrations, such as symmetrical inter-chromosomal translocations, is available: whole chromosome fluorescence in situ hybridization (FISH) staining. Asymmetrical translocations such as dicentric chromosomes are known to be lethal but cells with symmetrical translocations may survive and persist in the progeny population for years. Chromosome banding techniques can also detect inter-chromosomal translocations but understanding banding patterns requires professional training and experience. Due to its clear detection by a discernible painting color, whole chromosome painting method is superior in identifying chromosome fragmentation, loss, and amplification of chromosomes. This chapter introduces whole chromosome FISH painting method to detect chromosomal aberrations such asfragments and translocations.