Molecular Cytogenetics in the Era of Chromosomics and Cytogenomic Approaches

Abstract

Here the role of molecular cytogenetics in the context of yet available all other cytogenomic approaches is discussed. A short introduction how cytogenetics and molecular cytogenetics were established is followed by technical aspects of fluorescence in situ hybridization (FISH). The latter contains the methodology itself, the types of probe- and target-DNA, as well as probe sets. The main part deals with examples of modern FISH-applications, highlighting unique possibilities of the approach, like the possibility to study individual cells and even individual chromosomes. Different variants of FISH can be used to retrieve information on genomes from (almost) base pair to whole genomic level, as besides only second and third generation sequencing approaches can do. Here especially highlighted variations of FISH are molecular combing, chromosome orientation-FISH (CO-FISH), telomere-FISH, parental origin determination FISH (POD-FISH), FISH to resolve the nuclear architecture, multicolor-FISH (mFISH) approaches, among other applied in chromoanagenesis studies, Comet-FISH, and CRISPR-mediated FISH-applications. Overall, molecular cytogenetics is far from being outdated and actively involved in up-to-date diagnostics and research.

Case Report: How whole-genome sequencing-based cell-free DNA prenatal testing can help identify a marker mhromosome

“…Small supernumerary marker chromosomes are rare; it is estimated that there are ∼3.3 million SMC carriers worldwide, of which ∼2.2 million are asymptomatic ( Liehr, 2021 ). These marker chromosomes can originate from any of the human chromosomes.…”

Plant Cytogenetics in the Micronuclei Investigation—The Past, Current Status, and Perspectives

“…The early and current achievements of molecular cytogenetics have led to progress in the detection and detailed characterization of micronuclei (MN) [32,33]. Modern cytogenetics techniques have revolutionized knowledge on the composition and genetic activity of the chromatin that is involved in micronuclei.…”

How to Obtain High‐Quality Metaphase Spreads for Molecular Cytogenetics

“…FISH is well-established, and multiple probe sets have been developed to address diagnostic problems in tumor and clinical genetics, the latter including prenatal and postnatal cases (Liehr, 2021). When FISH-probe sets are being applied to metaphase nuclei, it is desirable to obtain clear signals on well-spread chromosomes, which optimally should be identifiable by an inverted DAPI-banding pattern.…”

“…The method presented here is helpful in molecular cytogenetics, specifically in preparing high-quality metaphase spreads to be evaluated after fluorescence in situ hybridization (FISH). The area of molecular cytogenetics developed from banding cytogenetics in the 1980s and belongs to the concert of cytogenetic approaches being applied in research and diagnostics (known as chromosomics) (reviewed in Liehr, 2021). Chromosomics aims to uncover the underlying principles of genetics and genomics to achieve a general understanding of life itself (Claussen, 2005).…”