Molecular Cytogenetics Manual (original) (raw)
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The Use of Molecular Cytogenetic Techniques for the Identification of Chromosomal Abnormalities
2017
Chromosomal analysis is an increasingly important diagnostic procedure in numerous areas of clinical medicine that includes haematology, perinatology or obstetrics. Chromosomal disorders are viewed as a major category of genetic diseases, and sometimes the identification of abnormal chromosomes is not easily applicable. Just like the identification of the marker chromosome or the identification of the complex karyotypes is important in clinics for the evaluation of the patient prognosis as well as the treatment response, needless to say; fluorescence in situ hybridization (FISH) is the most suitable and rapid method in the above-mentioned situations. It gives chance to the rapid analysis of chromosomal aneuploidies in dividing and non-dividing cells. In this chapter, we will discuss the general principles of the chromosomal abnormalities and the molecular cytogenetic techniques that can help the identification of presence or absence of a particular DNA sequence or the evaluation of ...
Molecular Cytogenetics in the Era of Chromosomics and Cytogenomic Approaches
Frontiers in Genetics, 2021
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-...
Detection of chromosomal abnormalities using fluorescence in situ hybridization (FISH)
The National medical journal of India
A number of studies have demonstrated the use of molecular cytogenetic techniques for clinical diagnosis. We compared the results of FISH analysis and conventional cytogenetics on different tissue samples for detection of chromosomal aberrations and to assess the utility of FISH assay for clinical diagnosis. Karyotypic analysis was carried out on 50 samples--20 peripheral blood samples, 20 bone marrow samples and 10 prenatal (chorionic villi/amniotic fluid) samples. The same chromosome preparations were further subjected to FISH analysis using probes specific for chromosome X, Y, 21 or bcr-abl gene. The results of FISH analysis were in conformity with the cytogenetic results in all the samples except one. FISH analysis could reveal hybridization signals even on poorly spread metaphase chromosomes and interphase nuclei. It was also possible to detect subtle chromosomal aberrations which were not detected using conventional chromosomal analysis. FISH is a powerful, sensitive molecular...
Historical prospective of human cytogenetics: from microscope to microarray
Clinical Biochemistry, 2004
After the fundamental discovery in 1956 that normal human cells contain 46 chromosomes, clinical cytogenetics was born and studies into the relation of chromosomal defects and disease could begin. Although many technical advances have been made over this long period, including the introduction of molecular techniques, until now, all cytogenetic studies have been performed through regular microscopes, which was throughout the years the most important equipment of a cytogenetic laboratory. However, recently a new technique has been introduced based on comparative genomic hybridization on an array of thousands of different probes (array-CGH). This technique enables an increase in the sensitivity of detecting chromosomal aberrations far beyond the detection limit of regular banding techniques. Furthermore, it gives us the possibility to detect genomic changes in malignant cells in cases where aberrations are too complex to study or when chromosomes are not available at all. Cytogenetic laboratories are now challenged to introduce and incorporate this new application next to the various well-established microscopical techniques to provide optimal diagnostic services.
The word “chromosome” was introduced over a century ago from the Greek language meaning “colored body.” While cytogenetics refers to the study of chromosomes, the term molecular cytogenetics is used to describe the analysis of genomic alterations using mainly in situ hybridization based technology. Fluorescent in situ hybridization (FISH) was initially developed in the late 1980s from radioactive hybridization procedures used for mapping human genes (1–4). Soon, this technology was utilized for the characterization of chromosomal rearrangements and marker chromosomes (5,6), the detection of microdeletions (7), and the prenatal diagnosis of common aneuploidies (8,9) in clinical cytogenetics laboratories. At the same time, numerous DNA probes have been commercialized, further promoting the wide-spread clinical applications of molecular cytogenetics. Many new FISH techniques have been developed, including primed in situ labeling (PRINS [10]), fiber FISH (11,12), comparative genomic hybridization (CGH) (13), chromosome microdissection (14,15), spectral karyotyping (SKY [16]), Multiple color FISH (M-FISH [17,18]), color banding (19), FISH with multiple subtelomeric probes (20), and arraybased CGH (21,22). With the current FISH techniques, deletion or rearrangement of a single gene can be detected, cryptic chromosome translocations can be visualized, the copy number of oncogenes amplified in tumor cells can be assessed, and very complex rearrangements can be fully characterized. Using interphase FISH, genomic alterations can be studied in virtually all types of human tissues at any stage of cell division, without the need of cell culture and chromosome preparation. The development of FISH technology in the past two decades has brought cytogenetics into the molecular era, and made the “colored bodies” more colorful and brighter.
Human molecular cytogenetics: from cells to nucleotides
Genetics and Molecular Biology, 2014
The field of cytogenetics has focused on studying the number, structure, function and origin of chromosomal abnormalities and the evolution of chromosomes. The development of fluorescent molecules that either directly or via an intermediate molecule bind to DNA has led to the development of fluorescent in situ hybridization (FISH), a technology linking cytogenetics to molecular genetics. This technique has a wide range of applications that increased the dimension of chromosome analysis. The field of cytogenetics is particularly important for medical diagnostics and research as well as for gene ordering and mapping. Furthermore, the increased application of molecular biology techniques, such as array-based technologies, has led to improved resolution, extending the recognized range of microdeletion/microduplication syndromes and genomic disorders. In adopting these newly expanded methods, cytogeneticists have used a range of technologies to study the association between visible chromosome rearrangements and defects at the single nucleotide level. Overall, molecular cytogenetic techniques offer a remarkable number of potential applications, ranging from physical mapping to clinical and evolutionary studies, making a powerful and informative complement to other molecular and genomic approaches. This manuscript does not present a detailed history of the development of molecular cytogenetics; however, references to historical reviews and experiments have been provided whenever possible. Herein, the basic principles of molecular cytogenetics, the technologies used to identify chromosomal rearrangements and copy number changes, and the applications for cytogenetics in biomedical diagnosis and research are presented and discussed.