Detection of Inter-chromosomal Stable Aberrations by Multiple Fluorescence <em>In Situ</em> Hybridization (mFISH) and Spectral Karyotyping (SKY) in Irradiated Mice

Abstract

Ionizing radiation (IR) induces numerous stable and unstable chromosomal aberrations. Unstable aberrations, where chromosome morphology is substantially compromised, can easily be identified by conventional chromosome staining techniques. However, detection of stable aberrations, which involve exchange or translocation of genetic materials without considerable modification in the chromosome morphology, requires sophisticated chromosome painting techniques that rely on in situ hybridization of fluorescently labeled DNA probes, a chromosome painting technique popularly known as fluorescence in situ hybridization (FISH). FISH probes can be specific for whole chromosome/s or precise sub-region on chromosome/s. The method not only allows visualization of stable aberrations, but it can also allow detection of the chromosome/s or specific DNA sequence/s involved in a particular aberration formation. A variety of chromosome painting techniques are available in cytogenetics; here two highly sensitive methods, multiple fluorescence in situ hybridization (mFISH) and spectral karyotyping (SKY), are discussed to identify inter-chromosomal stable aberrations that form in the bone marrow cells of mice after exposure to total body irradiation. Although both techniques rely on fluorescent labeled DNA probes, the method of detection and the process of image acquisition of the fluorescent signals are different. These two techniques have been used in various research areas, such as radiation biology, cancer cytogenetics, retrospective radiation biodosimetry, clinical cytogenetics, evolutionary cytogenetics, and comparative cytogenetics.

Multicolor Fluorescence In Situ Hybridization (FISH) Approaches for Simultaneous Analysis of the Entire Human Genome

“…Currently both SKY and M‐FISH have commercial assay kits that support multiple species including human, rat, and mouse (for more information see the website links of the Applied Spectral Imaging and MetaSystems Imaging in the Internet resources). Since their introduction, SKY and M‐FISH have been widely used in a variety of research studies and clinical cytogenetics, especially for the delineation of chromosomal rearrangements in neoplastic cases (Conde et al., ; Guo, Han, Wu, Da, & Zhu, ; Minakata et al., ; Morishita et al., ; Pathak, Koturbash, & Hauer‐Jensen, ; Rozenblum et al., ; Yuan et al., ; Wafa et al., ; for a current bibliography, visit the Applied Spectral Imaging and MetaSystems websites, respectively).…”